changing state of an LED using a pushbutton leads to unstable result












1















I am trying to run this code:



const int buttonPin = 7;     
const int ledPin13 = 13;

int buttonState = 0;
int lastButtonState = buttonState;
bool flag = true;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin13, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {

buttonState = digitalRead(buttonPin);


if (buttonState = HIGH && lastButtonState != buttonState) {
flag = !flag;
if (flag){
digitalWrite(ledPin13, LOW);
} else {
digitalWrite(ledPin13, HIGH);
}
}
}


on this SimulIDE model:






<circuit reactStep="50" animate="0" type="simulide_0.1" noLinStep="10" noLinAcc="5" speed="1000000">

Node-16:
<item labelrot="0" y="-204" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-220" labelx="-16" labely="-24" Show_id="false" objectName="Node-16" itemtype="Node" id="Node-16" rotation="0"/>

Arduino Uno-4:
<item hflip="1" Show_id="true" valLabely="0" itemtype="Arduino" vflip="1" labelx="0" objectName="Arduino Uno-4" labely="-20" y="-244" Ser_Port="false" labelrot="0" rotation="0" Program="../../Google Drive/Active projects/SRL/Students/Damian2019/Simulation/20190409/noDelay_20190409/noDelay_20190409.ino.standard.hex" Ser_Monitor="false" id="Arduino Uno-4" valLabelx="0" Mhz="16" valLabRot="0" x="-148"/>

Resistor-3:
<item Unit=" O" hflip="1" Show_id="false" valLabely="6" itemtype="Resistor" Show_res="true" vflip="1" labelx="-12" objectName="Resistor-3" labely="-24" y="-164" labelrot="0" rotation="-90" Resistance="100" id="Resistor-3" valLabelx="-16" valLabRot="0" x="-220"/>

Push-2:
<item labelrot="0" y="-308" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-100" labelx="-16" labely="-24" Show_id="false" objectName="Push-2" itemtype="Push" id="Push-2" rotation="0"/>

Connector-5:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Resistor-3-lPin" labelx="-16" objectName="Connector-5" labely="-24" y="-148" endpinid="Arduino Uno-4-GND0" enodeid="Circ_eNode-6" labelrot="0" pointList="-220,-148,-220,-108,-140,-108" rotation="0" id="Connector-5" valLabelx="0" valLabRot="0" x="-220"/>

Connector-11:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-rnod" labelx="-16" objectName="Connector-11" labely="-24" y="-308" endpinid="Arduino Uno-4-V5V" enodeid="Circ_eNode-12" labelrot="0" pointList="-84,-308,44,-308,44,-148,4,-148" rotation="0" id="Connector-11" valLabelx="0" valLabRot="0" x="-84"/>

Connector-9:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-lnod" labelx="-16" objectName="Connector-9" labely="-24" y="-308" endpinid="Node-16-0" enodeid="enode-15" labelrot="0" pointList="-116,-308,-220,-308,-220,-204" rotation="0" id="Connector-9" valLabelx="0" valLabRot="0" x="-116"/>

Connector-15:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Arduino Uno-4-PD7" labelx="-16" objectName="Connector-15" labely="-24" y="-172" endpinid="Node-16-1" enodeid="enode-15" labelrot="0" pointList="-140,-172,-172,-172,-172,-204,-220,-204" rotation="0" id="Connector-15" valLabelx="0" valLabRot="0" x="-140"/>

Connector-17:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Node-16-2" labelx="-16" objectName="Connector-17" labely="-24" y="-204" endpinid="Resistor-3-rPin" enodeid="enode-15" labelrot="0" pointList="-220,-204,-220,-180" rotation="0" id="Connector-17" valLabelx="0" valLabRot="0" x="-220"/>

PlotterWidget-13:
<item modal="false" childrenRect="" normalGeometry="" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="200" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="200" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="200" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" MinVolt="-500" fullScreen="false" windowTitle="" windowIcon="" maximumWidth="1000" objectName="PlotterWidget-13" toolTip="" toolTipDuration="-1" focus="false" MaxVolt="500" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="200" minimumHeight="200" size="" focusPolicy="0" itemtype="Plotter" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

SerialPortWidget-14:
<item modal="false" childrenRect="" normalGeometry="" SettingsProp="COM1,0,3,0,0,0" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="170" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="141" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="313" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" fullScreen="false" windowTitle="Settings" windowIcon="" maximumWidth="450" objectName="SerialPortWidget-14" toolTip="" toolTipDuration="-1" focus="false" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="0" minimumHeight="0" size="" focusPolicy="0" itemtype="SerialPort" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

</circuit>




and I expect the LED to be turned on-off everytime I push the button, however the result is unstable:






I would appreciate if you could help me know if there is something wrong with my code or circuit and I should expect the same behavior on an actual hardware, or this is a simulation issue?



P.S.1. All file can also be downloaded from here.



P.S.2. I'm using this example from Arduino.org website.



P.S.3. I also tried using an actual Arduino, also implementing the suggestions below. However the issue is not resolved. You may see the video here.










share|improve this question

























  • You need the state-change-detection: arduino.cc/en/Tutorial/StateChangeDetection

    – Jot
    2 days ago
















1















I am trying to run this code:



const int buttonPin = 7;     
const int ledPin13 = 13;

int buttonState = 0;
int lastButtonState = buttonState;
bool flag = true;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin13, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {

buttonState = digitalRead(buttonPin);


if (buttonState = HIGH && lastButtonState != buttonState) {
flag = !flag;
if (flag){
digitalWrite(ledPin13, LOW);
} else {
digitalWrite(ledPin13, HIGH);
}
}
}


on this SimulIDE model:






<circuit reactStep="50" animate="0" type="simulide_0.1" noLinStep="10" noLinAcc="5" speed="1000000">

Node-16:
<item labelrot="0" y="-204" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-220" labelx="-16" labely="-24" Show_id="false" objectName="Node-16" itemtype="Node" id="Node-16" rotation="0"/>

Arduino Uno-4:
<item hflip="1" Show_id="true" valLabely="0" itemtype="Arduino" vflip="1" labelx="0" objectName="Arduino Uno-4" labely="-20" y="-244" Ser_Port="false" labelrot="0" rotation="0" Program="../../Google Drive/Active projects/SRL/Students/Damian2019/Simulation/20190409/noDelay_20190409/noDelay_20190409.ino.standard.hex" Ser_Monitor="false" id="Arduino Uno-4" valLabelx="0" Mhz="16" valLabRot="0" x="-148"/>

Resistor-3:
<item Unit=" O" hflip="1" Show_id="false" valLabely="6" itemtype="Resistor" Show_res="true" vflip="1" labelx="-12" objectName="Resistor-3" labely="-24" y="-164" labelrot="0" rotation="-90" Resistance="100" id="Resistor-3" valLabelx="-16" valLabRot="0" x="-220"/>

Push-2:
<item labelrot="0" y="-308" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-100" labelx="-16" labely="-24" Show_id="false" objectName="Push-2" itemtype="Push" id="Push-2" rotation="0"/>

Connector-5:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Resistor-3-lPin" labelx="-16" objectName="Connector-5" labely="-24" y="-148" endpinid="Arduino Uno-4-GND0" enodeid="Circ_eNode-6" labelrot="0" pointList="-220,-148,-220,-108,-140,-108" rotation="0" id="Connector-5" valLabelx="0" valLabRot="0" x="-220"/>

Connector-11:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-rnod" labelx="-16" objectName="Connector-11" labely="-24" y="-308" endpinid="Arduino Uno-4-V5V" enodeid="Circ_eNode-12" labelrot="0" pointList="-84,-308,44,-308,44,-148,4,-148" rotation="0" id="Connector-11" valLabelx="0" valLabRot="0" x="-84"/>

Connector-9:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-lnod" labelx="-16" objectName="Connector-9" labely="-24" y="-308" endpinid="Node-16-0" enodeid="enode-15" labelrot="0" pointList="-116,-308,-220,-308,-220,-204" rotation="0" id="Connector-9" valLabelx="0" valLabRot="0" x="-116"/>

Connector-15:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Arduino Uno-4-PD7" labelx="-16" objectName="Connector-15" labely="-24" y="-172" endpinid="Node-16-1" enodeid="enode-15" labelrot="0" pointList="-140,-172,-172,-172,-172,-204,-220,-204" rotation="0" id="Connector-15" valLabelx="0" valLabRot="0" x="-140"/>

Connector-17:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Node-16-2" labelx="-16" objectName="Connector-17" labely="-24" y="-204" endpinid="Resistor-3-rPin" enodeid="enode-15" labelrot="0" pointList="-220,-204,-220,-180" rotation="0" id="Connector-17" valLabelx="0" valLabRot="0" x="-220"/>

PlotterWidget-13:
<item modal="false" childrenRect="" normalGeometry="" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="200" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="200" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="200" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" MinVolt="-500" fullScreen="false" windowTitle="" windowIcon="" maximumWidth="1000" objectName="PlotterWidget-13" toolTip="" toolTipDuration="-1" focus="false" MaxVolt="500" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="200" minimumHeight="200" size="" focusPolicy="0" itemtype="Plotter" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

SerialPortWidget-14:
<item modal="false" childrenRect="" normalGeometry="" SettingsProp="COM1,0,3,0,0,0" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="170" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="141" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="313" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" fullScreen="false" windowTitle="Settings" windowIcon="" maximumWidth="450" objectName="SerialPortWidget-14" toolTip="" toolTipDuration="-1" focus="false" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="0" minimumHeight="0" size="" focusPolicy="0" itemtype="SerialPort" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

</circuit>




and I expect the LED to be turned on-off everytime I push the button, however the result is unstable:






I would appreciate if you could help me know if there is something wrong with my code or circuit and I should expect the same behavior on an actual hardware, or this is a simulation issue?



P.S.1. All file can also be downloaded from here.



P.S.2. I'm using this example from Arduino.org website.



P.S.3. I also tried using an actual Arduino, also implementing the suggestions below. However the issue is not resolved. You may see the video here.










share|improve this question

























  • You need the state-change-detection: arduino.cc/en/Tutorial/StateChangeDetection

    – Jot
    2 days ago














1












1








1








I am trying to run this code:



const int buttonPin = 7;     
const int ledPin13 = 13;

int buttonState = 0;
int lastButtonState = buttonState;
bool flag = true;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin13, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {

buttonState = digitalRead(buttonPin);


if (buttonState = HIGH && lastButtonState != buttonState) {
flag = !flag;
if (flag){
digitalWrite(ledPin13, LOW);
} else {
digitalWrite(ledPin13, HIGH);
}
}
}


on this SimulIDE model:






<circuit reactStep="50" animate="0" type="simulide_0.1" noLinStep="10" noLinAcc="5" speed="1000000">

Node-16:
<item labelrot="0" y="-204" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-220" labelx="-16" labely="-24" Show_id="false" objectName="Node-16" itemtype="Node" id="Node-16" rotation="0"/>

Arduino Uno-4:
<item hflip="1" Show_id="true" valLabely="0" itemtype="Arduino" vflip="1" labelx="0" objectName="Arduino Uno-4" labely="-20" y="-244" Ser_Port="false" labelrot="0" rotation="0" Program="../../Google Drive/Active projects/SRL/Students/Damian2019/Simulation/20190409/noDelay_20190409/noDelay_20190409.ino.standard.hex" Ser_Monitor="false" id="Arduino Uno-4" valLabelx="0" Mhz="16" valLabRot="0" x="-148"/>

Resistor-3:
<item Unit=" O" hflip="1" Show_id="false" valLabely="6" itemtype="Resistor" Show_res="true" vflip="1" labelx="-12" objectName="Resistor-3" labely="-24" y="-164" labelrot="0" rotation="-90" Resistance="100" id="Resistor-3" valLabelx="-16" valLabRot="0" x="-220"/>

Push-2:
<item labelrot="0" y="-308" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-100" labelx="-16" labely="-24" Show_id="false" objectName="Push-2" itemtype="Push" id="Push-2" rotation="0"/>

Connector-5:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Resistor-3-lPin" labelx="-16" objectName="Connector-5" labely="-24" y="-148" endpinid="Arduino Uno-4-GND0" enodeid="Circ_eNode-6" labelrot="0" pointList="-220,-148,-220,-108,-140,-108" rotation="0" id="Connector-5" valLabelx="0" valLabRot="0" x="-220"/>

Connector-11:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-rnod" labelx="-16" objectName="Connector-11" labely="-24" y="-308" endpinid="Arduino Uno-4-V5V" enodeid="Circ_eNode-12" labelrot="0" pointList="-84,-308,44,-308,44,-148,4,-148" rotation="0" id="Connector-11" valLabelx="0" valLabRot="0" x="-84"/>

Connector-9:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-lnod" labelx="-16" objectName="Connector-9" labely="-24" y="-308" endpinid="Node-16-0" enodeid="enode-15" labelrot="0" pointList="-116,-308,-220,-308,-220,-204" rotation="0" id="Connector-9" valLabelx="0" valLabRot="0" x="-116"/>

Connector-15:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Arduino Uno-4-PD7" labelx="-16" objectName="Connector-15" labely="-24" y="-172" endpinid="Node-16-1" enodeid="enode-15" labelrot="0" pointList="-140,-172,-172,-172,-172,-204,-220,-204" rotation="0" id="Connector-15" valLabelx="0" valLabRot="0" x="-140"/>

Connector-17:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Node-16-2" labelx="-16" objectName="Connector-17" labely="-24" y="-204" endpinid="Resistor-3-rPin" enodeid="enode-15" labelrot="0" pointList="-220,-204,-220,-180" rotation="0" id="Connector-17" valLabelx="0" valLabRot="0" x="-220"/>

PlotterWidget-13:
<item modal="false" childrenRect="" normalGeometry="" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="200" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="200" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="200" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" MinVolt="-500" fullScreen="false" windowTitle="" windowIcon="" maximumWidth="1000" objectName="PlotterWidget-13" toolTip="" toolTipDuration="-1" focus="false" MaxVolt="500" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="200" minimumHeight="200" size="" focusPolicy="0" itemtype="Plotter" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

SerialPortWidget-14:
<item modal="false" childrenRect="" normalGeometry="" SettingsProp="COM1,0,3,0,0,0" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="170" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="141" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="313" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" fullScreen="false" windowTitle="Settings" windowIcon="" maximumWidth="450" objectName="SerialPortWidget-14" toolTip="" toolTipDuration="-1" focus="false" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="0" minimumHeight="0" size="" focusPolicy="0" itemtype="SerialPort" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

</circuit>




and I expect the LED to be turned on-off everytime I push the button, however the result is unstable:






I would appreciate if you could help me know if there is something wrong with my code or circuit and I should expect the same behavior on an actual hardware, or this is a simulation issue?



P.S.1. All file can also be downloaded from here.



P.S.2. I'm using this example from Arduino.org website.



P.S.3. I also tried using an actual Arduino, also implementing the suggestions below. However the issue is not resolved. You may see the video here.










share|improve this question
















I am trying to run this code:



const int buttonPin = 7;     
const int ledPin13 = 13;

int buttonState = 0;
int lastButtonState = buttonState;
bool flag = true;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin13, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {

buttonState = digitalRead(buttonPin);


if (buttonState = HIGH && lastButtonState != buttonState) {
flag = !flag;
if (flag){
digitalWrite(ledPin13, LOW);
} else {
digitalWrite(ledPin13, HIGH);
}
}
}


on this SimulIDE model:






<circuit reactStep="50" animate="0" type="simulide_0.1" noLinStep="10" noLinAcc="5" speed="1000000">

Node-16:
<item labelrot="0" y="-204" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-220" labelx="-16" labely="-24" Show_id="false" objectName="Node-16" itemtype="Node" id="Node-16" rotation="0"/>

Arduino Uno-4:
<item hflip="1" Show_id="true" valLabely="0" itemtype="Arduino" vflip="1" labelx="0" objectName="Arduino Uno-4" labely="-20" y="-244" Ser_Port="false" labelrot="0" rotation="0" Program="../../Google Drive/Active projects/SRL/Students/Damian2019/Simulation/20190409/noDelay_20190409/noDelay_20190409.ino.standard.hex" Ser_Monitor="false" id="Arduino Uno-4" valLabelx="0" Mhz="16" valLabRot="0" x="-148"/>

Resistor-3:
<item Unit=" O" hflip="1" Show_id="false" valLabely="6" itemtype="Resistor" Show_res="true" vflip="1" labelx="-12" objectName="Resistor-3" labely="-24" y="-164" labelrot="0" rotation="-90" Resistance="100" id="Resistor-3" valLabelx="-16" valLabRot="0" x="-220"/>

Push-2:
<item labelrot="0" y="-308" valLabRot="0" valLabelx="0" valLabely="0" hflip="1" vflip="1" x="-100" labelx="-16" labely="-24" Show_id="false" objectName="Push-2" itemtype="Push" id="Push-2" rotation="0"/>

Connector-5:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Resistor-3-lPin" labelx="-16" objectName="Connector-5" labely="-24" y="-148" endpinid="Arduino Uno-4-GND0" enodeid="Circ_eNode-6" labelrot="0" pointList="-220,-148,-220,-108,-140,-108" rotation="0" id="Connector-5" valLabelx="0" valLabRot="0" x="-220"/>

Connector-11:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-rnod" labelx="-16" objectName="Connector-11" labely="-24" y="-308" endpinid="Arduino Uno-4-V5V" enodeid="Circ_eNode-12" labelrot="0" pointList="-84,-308,44,-308,44,-148,4,-148" rotation="0" id="Connector-11" valLabelx="0" valLabRot="0" x="-84"/>

Connector-9:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Push-2-lnod" labelx="-16" objectName="Connector-9" labely="-24" y="-308" endpinid="Node-16-0" enodeid="enode-15" labelrot="0" pointList="-116,-308,-220,-308,-220,-204" rotation="0" id="Connector-9" valLabelx="0" valLabRot="0" x="-116"/>

Connector-15:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Arduino Uno-4-PD7" labelx="-16" objectName="Connector-15" labely="-24" y="-172" endpinid="Node-16-1" enodeid="enode-15" labelrot="0" pointList="-140,-172,-172,-172,-172,-204,-220,-204" rotation="0" id="Connector-15" valLabelx="0" valLabRot="0" x="-140"/>

Connector-17:
<item hflip="1" Show_id="false" valLabely="0" itemtype="Connector" vflip="1" startpinid="Node-16-2" labelx="-16" objectName="Connector-17" labely="-24" y="-204" endpinid="Resistor-3-rPin" enodeid="enode-15" labelrot="0" pointList="-220,-204,-220,-180" rotation="0" id="Connector-17" valLabelx="0" valLabRot="0" x="-220"/>

PlotterWidget-13:
<item modal="false" childrenRect="" normalGeometry="" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="200" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="200" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="200" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" MinVolt="-500" fullScreen="false" windowTitle="" windowIcon="" maximumWidth="1000" objectName="PlotterWidget-13" toolTip="" toolTipDuration="-1" focus="false" MaxVolt="500" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="200" minimumHeight="200" size="" focusPolicy="0" itemtype="Plotter" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

SerialPortWidget-14:
<item modal="false" childrenRect="" normalGeometry="" SettingsProp="COM1,0,3,0,0,0" baseSize="" geometry="" sizeIncrement="" windowOpacity="1" windowModified="false" enabled="true" maximumSize="" childrenRegion="" maximumHeight="170" inputMethodHints="0" mouseTracking="false" minimumSize="" frameGeometry="" sizeHint="" windowIconText="" locale="" minimumSizeHint="" height="141" isActiveWindow="true" x="0" accessibleName="" layoutDirection="0" autoFillBackground="false" width="313" windowFilePath="" windowModality="0" maximized="false" sizePolicy="" fullScreen="false" windowTitle="Settings" windowIcon="" maximumWidth="450" objectName="SerialPortWidget-14" toolTip="" toolTipDuration="-1" focus="false" palette="" font="MS Shell Dlg 2,8.25,-1,5,50,0,0,0,0,0" whatsThis="" pos="" minimumWidth="0" minimumHeight="0" size="" focusPolicy="0" itemtype="SerialPort" updatesEnabled="true" accessibleDescription="" y="0" rect="" frameSize="" minimized="false" acceptDrops="false" styleSheet="" cursor="" visible="false" statusTip="" contextMenuPolicy="1"/>

</circuit>




and I expect the LED to be turned on-off everytime I push the button, however the result is unstable:






I would appreciate if you could help me know if there is something wrong with my code or circuit and I should expect the same behavior on an actual hardware, or this is a simulation issue?



P.S.1. All file can also be downloaded from here.



P.S.2. I'm using this example from Arduino.org website.



P.S.3. I also tried using an actual Arduino, also implementing the suggestions below. However the issue is not resolved. You may see the video here.







arduino-uno led button






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 2 days ago







Foad

















asked 2 days ago









FoadFoad

1185




1185













  • You need the state-change-detection: arduino.cc/en/Tutorial/StateChangeDetection

    – Jot
    2 days ago



















  • You need the state-change-detection: arduino.cc/en/Tutorial/StateChangeDetection

    – Jot
    2 days ago

















You need the state-change-detection: arduino.cc/en/Tutorial/StateChangeDetection

– Jot
2 days ago





You need the state-change-detection: arduino.cc/en/Tutorial/StateChangeDetection

– Jot
2 days ago










4 Answers
4






active

oldest

votes


















2














Certain Changes in your code:



const int buttonPin = 7;     
const int ledPin13 = 13;

int buttonState = 0;
int lastButtonState = buttonState;
bool flag = true;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin13, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {

buttonState = digitalRead(buttonPin);


if (buttonState == HIGH && lastButtonState != buttonState) {
lastButtonState = buttonState;
flag =!flag;
if (flag){
digitalWrite(ledPin13, LOW);
} else {
digitalWrite(ledPin13, HIGH);
}
}
}


Secondly your hardware model is not good.
ANODE of LED must be connected to PIN13 and Cathode to GND. And switch must be placed between 3.3 V and Pin7 only.
In your model by closing switch you are shorting 3.3V and GND. If you had provided an external pullup then you should use at minimum a 4.7K resistor value. 100ohm never works.



I don't have software for Design so I used Paint and made a sketch for you.





schematic





simulate this circuit – Schematic created using CircuitLab






share|improve this answer


























  • ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

    – Foad
    2 days ago











  • The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

    – Duncan C
    2 days ago











  • In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

    – Duncan C
    2 days ago






  • 2





    There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

    – orithena
    2 days ago



















2














I identify a few problems here:




  • The 100 Ohm pulldown resistor for the button is way too low. 1 kOhm to 100 kOhm is typically used here.


  • if( buttonState = HIGH ) does not compare, it assigns buttonState to HIGH (overwriting the value read with digitalRead(buttonPin)). Use the compare-for-equality operator == here, otherwise the if just checks if buttonState has been assigned a "truthlike" value (incidentally, HIGH is one of them).

  • As others have already commented, lastButtonState must be set somewhere after the if-block!


Since many Arduinos do have pullup resistors built in, I'd say: drop the resistor completely, instead initialize the button input pin (7) to use its built-in pullup resistor ... this will invert the logic and you'll have to connect the button between pin 7 and GND (i.e. swapping button and resistor), though:



    pinMode(buttonPin, INPUT_PULLUP);


This will have the same result as if you replaced the 100 Ohm resistor with a 20 kOhm resistor after swapping button and resistor -- but that resistor is now inside the Arduino. (Take care if you use "Arduino-compatible" boards; sometimes they lack the pullup resistors or have them fixed!).



There still is one problem: bouncing. Pressing a mechanical button leads to the contacts inside the button to bounce a bit against each other, leading to a very fast HIGH-LOW-HIGH-LOW-etc signal before it settles on the target state. You can alleviate this a bit by adding a delay(5) at the end of your loop(), but using a button library (e.g. Button, available in the Arduino IDE Library Manager) that debounces the signal will lead to better results most of the time.



This will lead to this code (also including the ternary operator hint by Michel Keijzers):



const int buttonPin = 7;     
const int ledPin13 = 13;

int buttonState = 0;
int lastButtonState = buttonState;
bool flag = true;

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin13, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
buttonState = digitalRead(buttonPin);

if (buttonState == LOW && lastButtonState != buttonState) {
flag = !flag;
digitalWrite(ledPin13, flag ? LOW : HIGH);
}

lastButtonState = buttonState;
delay(5);
}


This should do the trick (I didn't try it, though).






share|improve this answer










New contributor




orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





















  • OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

    – Foad
    2 days ago











  • ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

    – Foad
    2 days ago






  • 1





    @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

    – orithena
    2 days ago













  • could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

    – Foad
    yesterday











  • @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

    – orithena
    yesterday



















1














There are already great answers, but I also found out about the interrupt functionality:



const byte ledPin = 13;
const byte interruptPin = 2;
volatile byte state = LOW;

void setup() {
pinMode(ledPin, OUTPUT);
pinMode(interruptPin, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(interruptPin), blink, FALLING);
}

void loop() {
digitalWrite(ledPin, state);
}

void blink() {
state = !state;
}


some point:




  • no matter using interrupt or the methods above tho process will not achieve stable / deterministic result. The issue lies in the hardware of the push-button and there will be fluctuations which can be interpreted by the MCU. One way to alleviate is to use delay.

  • The


  • attachInterrupt has four modes LOW, Change, FALLING and RISING. The FALLING and RISING modes are the one to be used. the other two also lead to very unpredictable result.

  • Only pins 1 and 2 can be used for interrupts.

  • There is also the option to mix the two methods which you can see here, but I'm not sure if it will improve the stability.


I used this video and information on this page.






share|improve this answer

































    0














    This is a comment (but could not use text alignment in a comment):



    Instead of



    if (flag){
    digitalWrite(ledPin13, LOW);
    } else {
    digitalWrite(ledPin13, HIGH);
    }


    You can use:



    digitalWrite(ledPin13, flag ? LOW : HIGH);


    (It is functionally 100% equal though).






    share|improve this answer



















    • 1





      Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

      – Michel Keijzers
      2 days ago






    • 1





      Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

      – Michel Keijzers
      2 days ago






    • 1





      I do not understand why they down voted you. I appreciate your support anyway.

      – Foad
      2 days ago






    • 1





      Probably because it should be a comment (but code alignment is only possible inside an answer).

      – Michel Keijzers
      2 days ago








    • 1





      @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

      – orithena
      yesterday












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    4 Answers
    4






    active

    oldest

    votes








    4 Answers
    4






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    2














    Certain Changes in your code:



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT);
    }

    void loop() {

    buttonState = digitalRead(buttonPin);


    if (buttonState == HIGH && lastButtonState != buttonState) {
    lastButtonState = buttonState;
    flag =!flag;
    if (flag){
    digitalWrite(ledPin13, LOW);
    } else {
    digitalWrite(ledPin13, HIGH);
    }
    }
    }


    Secondly your hardware model is not good.
    ANODE of LED must be connected to PIN13 and Cathode to GND. And switch must be placed between 3.3 V and Pin7 only.
    In your model by closing switch you are shorting 3.3V and GND. If you had provided an external pullup then you should use at minimum a 4.7K resistor value. 100ohm never works.



    I don't have software for Design so I used Paint and made a sketch for you.





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer


























    • ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

      – Foad
      2 days ago











    • The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

      – Duncan C
      2 days ago











    • In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

      – Duncan C
      2 days ago






    • 2





      There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

      – orithena
      2 days ago
















    2














    Certain Changes in your code:



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT);
    }

    void loop() {

    buttonState = digitalRead(buttonPin);


    if (buttonState == HIGH && lastButtonState != buttonState) {
    lastButtonState = buttonState;
    flag =!flag;
    if (flag){
    digitalWrite(ledPin13, LOW);
    } else {
    digitalWrite(ledPin13, HIGH);
    }
    }
    }


    Secondly your hardware model is not good.
    ANODE of LED must be connected to PIN13 and Cathode to GND. And switch must be placed between 3.3 V and Pin7 only.
    In your model by closing switch you are shorting 3.3V and GND. If you had provided an external pullup then you should use at minimum a 4.7K resistor value. 100ohm never works.



    I don't have software for Design so I used Paint and made a sketch for you.





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer


























    • ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

      – Foad
      2 days ago











    • The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

      – Duncan C
      2 days ago











    • In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

      – Duncan C
      2 days ago






    • 2





      There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

      – orithena
      2 days ago














    2












    2








    2







    Certain Changes in your code:



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT);
    }

    void loop() {

    buttonState = digitalRead(buttonPin);


    if (buttonState == HIGH && lastButtonState != buttonState) {
    lastButtonState = buttonState;
    flag =!flag;
    if (flag){
    digitalWrite(ledPin13, LOW);
    } else {
    digitalWrite(ledPin13, HIGH);
    }
    }
    }


    Secondly your hardware model is not good.
    ANODE of LED must be connected to PIN13 and Cathode to GND. And switch must be placed between 3.3 V and Pin7 only.
    In your model by closing switch you are shorting 3.3V and GND. If you had provided an external pullup then you should use at minimum a 4.7K resistor value. 100ohm never works.



    I don't have software for Design so I used Paint and made a sketch for you.





    schematic





    simulate this circuit – Schematic created using CircuitLab






    share|improve this answer















    Certain Changes in your code:



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT);
    }

    void loop() {

    buttonState = digitalRead(buttonPin);


    if (buttonState == HIGH && lastButtonState != buttonState) {
    lastButtonState = buttonState;
    flag =!flag;
    if (flag){
    digitalWrite(ledPin13, LOW);
    } else {
    digitalWrite(ledPin13, HIGH);
    }
    }
    }


    Secondly your hardware model is not good.
    ANODE of LED must be connected to PIN13 and Cathode to GND. And switch must be placed between 3.3 V and Pin7 only.
    In your model by closing switch you are shorting 3.3V and GND. If you had provided an external pullup then you should use at minimum a 4.7K resistor value. 100ohm never works.



    I don't have software for Design so I used Paint and made a sketch for you.





    schematic





    simulate this circuit – Schematic created using CircuitLab







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 2 days ago









    Foad

    1185




    1185










    answered 2 days ago









    VaibhavVaibhav

    1124




    1124













    • ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

      – Foad
      2 days ago











    • The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

      – Duncan C
      2 days ago











    • In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

      – Duncan C
      2 days ago






    • 2





      There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

      – orithena
      2 days ago



















    • ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

      – Foad
      2 days ago











    • The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

      – Duncan C
      2 days ago











    • In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

      – Duncan C
      2 days ago






    • 2





      There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

      – orithena
      2 days ago

















    ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

    – Foad
    2 days ago





    ah my bad the lastButtonState = buttonState; was in the actual code but I dropped it accidentally in the example. would you be kind to draw the correct circuit? I'm not sure if I understand exactly what you mean.

    – Foad
    2 days ago













    The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

    – Duncan C
    2 days ago





    The OP is using 5V, not 3.3v. And how is his circuit's switch shorting 3.3V/5V to ground? If pin7 were an output, and LOW, it would be a low resistance path to ground. It might be a good idea to put a 1K resistor on Pin7.

    – Duncan C
    2 days ago













    In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

    – Duncan C
    2 days ago





    In your diagram, you need a current-limiting resistor on the LED or it will both draw too much current from pin13 and over-drive the LED (But I think the OP is using the built-in LED on pin 13 rather than adding an external LED.)

    – Duncan C
    2 days ago




    2




    2





    There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

    – orithena
    2 days ago





    There's still a problem in the code: lastButtonState will always be HIGH, because it is inside the if(buttonState == HIGH) block.

    – orithena
    2 days ago











    2














    I identify a few problems here:




    • The 100 Ohm pulldown resistor for the button is way too low. 1 kOhm to 100 kOhm is typically used here.


    • if( buttonState = HIGH ) does not compare, it assigns buttonState to HIGH (overwriting the value read with digitalRead(buttonPin)). Use the compare-for-equality operator == here, otherwise the if just checks if buttonState has been assigned a "truthlike" value (incidentally, HIGH is one of them).

    • As others have already commented, lastButtonState must be set somewhere after the if-block!


    Since many Arduinos do have pullup resistors built in, I'd say: drop the resistor completely, instead initialize the button input pin (7) to use its built-in pullup resistor ... this will invert the logic and you'll have to connect the button between pin 7 and GND (i.e. swapping button and resistor), though:



        pinMode(buttonPin, INPUT_PULLUP);


    This will have the same result as if you replaced the 100 Ohm resistor with a 20 kOhm resistor after swapping button and resistor -- but that resistor is now inside the Arduino. (Take care if you use "Arduino-compatible" boards; sometimes they lack the pullup resistors or have them fixed!).



    There still is one problem: bouncing. Pressing a mechanical button leads to the contacts inside the button to bounce a bit against each other, leading to a very fast HIGH-LOW-HIGH-LOW-etc signal before it settles on the target state. You can alleviate this a bit by adding a delay(5) at the end of your loop(), but using a button library (e.g. Button, available in the Arduino IDE Library Manager) that debounces the signal will lead to better results most of the time.



    This will lead to this code (also including the ternary operator hint by Michel Keijzers):



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT_PULLUP);
    }

    void loop() {
    buttonState = digitalRead(buttonPin);

    if (buttonState == LOW && lastButtonState != buttonState) {
    flag = !flag;
    digitalWrite(ledPin13, flag ? LOW : HIGH);
    }

    lastButtonState = buttonState;
    delay(5);
    }


    This should do the trick (I didn't try it, though).






    share|improve this answer










    New contributor




    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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    • OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

      – Foad
      2 days ago











    • ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

      – Foad
      2 days ago






    • 1





      @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

      – orithena
      2 days ago













    • could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

      – Foad
      yesterday











    • @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

      – orithena
      yesterday
















    2














    I identify a few problems here:




    • The 100 Ohm pulldown resistor for the button is way too low. 1 kOhm to 100 kOhm is typically used here.


    • if( buttonState = HIGH ) does not compare, it assigns buttonState to HIGH (overwriting the value read with digitalRead(buttonPin)). Use the compare-for-equality operator == here, otherwise the if just checks if buttonState has been assigned a "truthlike" value (incidentally, HIGH is one of them).

    • As others have already commented, lastButtonState must be set somewhere after the if-block!


    Since many Arduinos do have pullup resistors built in, I'd say: drop the resistor completely, instead initialize the button input pin (7) to use its built-in pullup resistor ... this will invert the logic and you'll have to connect the button between pin 7 and GND (i.e. swapping button and resistor), though:



        pinMode(buttonPin, INPUT_PULLUP);


    This will have the same result as if you replaced the 100 Ohm resistor with a 20 kOhm resistor after swapping button and resistor -- but that resistor is now inside the Arduino. (Take care if you use "Arduino-compatible" boards; sometimes they lack the pullup resistors or have them fixed!).



    There still is one problem: bouncing. Pressing a mechanical button leads to the contacts inside the button to bounce a bit against each other, leading to a very fast HIGH-LOW-HIGH-LOW-etc signal before it settles on the target state. You can alleviate this a bit by adding a delay(5) at the end of your loop(), but using a button library (e.g. Button, available in the Arduino IDE Library Manager) that debounces the signal will lead to better results most of the time.



    This will lead to this code (also including the ternary operator hint by Michel Keijzers):



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT_PULLUP);
    }

    void loop() {
    buttonState = digitalRead(buttonPin);

    if (buttonState == LOW && lastButtonState != buttonState) {
    flag = !flag;
    digitalWrite(ledPin13, flag ? LOW : HIGH);
    }

    lastButtonState = buttonState;
    delay(5);
    }


    This should do the trick (I didn't try it, though).






    share|improve this answer










    New contributor




    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.





















    • OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

      – Foad
      2 days ago











    • ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

      – Foad
      2 days ago






    • 1





      @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

      – orithena
      2 days ago













    • could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

      – Foad
      yesterday











    • @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

      – orithena
      yesterday














    2












    2








    2







    I identify a few problems here:




    • The 100 Ohm pulldown resistor for the button is way too low. 1 kOhm to 100 kOhm is typically used here.


    • if( buttonState = HIGH ) does not compare, it assigns buttonState to HIGH (overwriting the value read with digitalRead(buttonPin)). Use the compare-for-equality operator == here, otherwise the if just checks if buttonState has been assigned a "truthlike" value (incidentally, HIGH is one of them).

    • As others have already commented, lastButtonState must be set somewhere after the if-block!


    Since many Arduinos do have pullup resistors built in, I'd say: drop the resistor completely, instead initialize the button input pin (7) to use its built-in pullup resistor ... this will invert the logic and you'll have to connect the button between pin 7 and GND (i.e. swapping button and resistor), though:



        pinMode(buttonPin, INPUT_PULLUP);


    This will have the same result as if you replaced the 100 Ohm resistor with a 20 kOhm resistor after swapping button and resistor -- but that resistor is now inside the Arduino. (Take care if you use "Arduino-compatible" boards; sometimes they lack the pullup resistors or have them fixed!).



    There still is one problem: bouncing. Pressing a mechanical button leads to the contacts inside the button to bounce a bit against each other, leading to a very fast HIGH-LOW-HIGH-LOW-etc signal before it settles on the target state. You can alleviate this a bit by adding a delay(5) at the end of your loop(), but using a button library (e.g. Button, available in the Arduino IDE Library Manager) that debounces the signal will lead to better results most of the time.



    This will lead to this code (also including the ternary operator hint by Michel Keijzers):



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT_PULLUP);
    }

    void loop() {
    buttonState = digitalRead(buttonPin);

    if (buttonState == LOW && lastButtonState != buttonState) {
    flag = !flag;
    digitalWrite(ledPin13, flag ? LOW : HIGH);
    }

    lastButtonState = buttonState;
    delay(5);
    }


    This should do the trick (I didn't try it, though).






    share|improve this answer










    New contributor




    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.










    I identify a few problems here:




    • The 100 Ohm pulldown resistor for the button is way too low. 1 kOhm to 100 kOhm is typically used here.


    • if( buttonState = HIGH ) does not compare, it assigns buttonState to HIGH (overwriting the value read with digitalRead(buttonPin)). Use the compare-for-equality operator == here, otherwise the if just checks if buttonState has been assigned a "truthlike" value (incidentally, HIGH is one of them).

    • As others have already commented, lastButtonState must be set somewhere after the if-block!


    Since many Arduinos do have pullup resistors built in, I'd say: drop the resistor completely, instead initialize the button input pin (7) to use its built-in pullup resistor ... this will invert the logic and you'll have to connect the button between pin 7 and GND (i.e. swapping button and resistor), though:



        pinMode(buttonPin, INPUT_PULLUP);


    This will have the same result as if you replaced the 100 Ohm resistor with a 20 kOhm resistor after swapping button and resistor -- but that resistor is now inside the Arduino. (Take care if you use "Arduino-compatible" boards; sometimes they lack the pullup resistors or have them fixed!).



    There still is one problem: bouncing. Pressing a mechanical button leads to the contacts inside the button to bounce a bit against each other, leading to a very fast HIGH-LOW-HIGH-LOW-etc signal before it settles on the target state. You can alleviate this a bit by adding a delay(5) at the end of your loop(), but using a button library (e.g. Button, available in the Arduino IDE Library Manager) that debounces the signal will lead to better results most of the time.



    This will lead to this code (also including the ternary operator hint by Michel Keijzers):



    const int buttonPin = 7;     
    const int ledPin13 = 13;

    int buttonState = 0;
    int lastButtonState = buttonState;
    bool flag = true;

    void setup() {
    // initialize the LED pin as an output:
    pinMode(ledPin13, OUTPUT);
    // initialize the pushbutton pin as an input:
    pinMode(buttonPin, INPUT_PULLUP);
    }

    void loop() {
    buttonState = digitalRead(buttonPin);

    if (buttonState == LOW && lastButtonState != buttonState) {
    flag = !flag;
    digitalWrite(ledPin13, flag ? LOW : HIGH);
    }

    lastButtonState = buttonState;
    delay(5);
    }


    This should do the trick (I didn't try it, though).







    share|improve this answer










    New contributor




    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.









    share|improve this answer



    share|improve this answer








    edited yesterday





















    New contributor




    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.









    answered 2 days ago









    orithenaorithena

    1213




    1213




    New contributor




    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.





    New contributor





    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.






    orithena is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.













    • OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

      – Foad
      2 days ago











    • ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

      – Foad
      2 days ago






    • 1





      @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

      – orithena
      2 days ago













    • could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

      – Foad
      yesterday











    • @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

      – orithena
      yesterday



















    • OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

      – Foad
      2 days ago











    • ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

      – Foad
      2 days ago






    • 1





      @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

      – orithena
      2 days ago













    • could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

      – Foad
      yesterday











    • @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

      – orithena
      yesterday

















    OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

    – Foad
    2 days ago





    OMG how could I make such a mistake!!! Thanks for pointing it out. one issue you should consider is that Arduino uno doesn't have INPUT_PULLDOWN. Apparently only Zero has this? I get the error INPUT_PULLDOWN was not declared in this scope

    – Foad
    2 days ago













    ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

    – Foad
    2 days ago





    ok. it seems the pinMode(buttonPin, INPUT_PULLDOWN); is equivalent of pinMode(pin, INPUT); digitalWrite(pin, LOW); and pinMode(buttonPin, INPUT_PULLUP); is pinMode(pin, INPUT); digitalWrite(pin, HIGH); and that syntax doesn't work properly on some versions of Arduino IDE.

    – Foad
    2 days ago




    1




    1





    @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

    – orithena
    2 days ago







    @Foad You're right, according to arduino.cc/en/Tutorial/DigitalPins INPUT_PULLDOWN seems to be rather seldom... but INPUT_PULLUP should work. Using this would invert the logic on the button pin, though. I'll edit to reflect that.

    – orithena
    2 days ago















    could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

    – Foad
    yesterday





    could you be kind to 1. draw the circuit using the pullup resistor 2. point me a good button library? thanks again.

    – Foad
    yesterday













    @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

    – orithena
    yesterday





    @Foad I added a link to the most simple button library with debouncing from the Arduino IDE Library Manager; documentation is on its github page. Drawing the circuit must have to wait until I'm back home.

    – orithena
    yesterday











    1














    There are already great answers, but I also found out about the interrupt functionality:



    const byte ledPin = 13;
    const byte interruptPin = 2;
    volatile byte state = LOW;

    void setup() {
    pinMode(ledPin, OUTPUT);
    pinMode(interruptPin, INPUT_PULLUP);
    attachInterrupt(digitalPinToInterrupt(interruptPin), blink, FALLING);
    }

    void loop() {
    digitalWrite(ledPin, state);
    }

    void blink() {
    state = !state;
    }


    some point:




    • no matter using interrupt or the methods above tho process will not achieve stable / deterministic result. The issue lies in the hardware of the push-button and there will be fluctuations which can be interpreted by the MCU. One way to alleviate is to use delay.

    • The


    • attachInterrupt has four modes LOW, Change, FALLING and RISING. The FALLING and RISING modes are the one to be used. the other two also lead to very unpredictable result.

    • Only pins 1 and 2 can be used for interrupts.

    • There is also the option to mix the two methods which you can see here, but I'm not sure if it will improve the stability.


    I used this video and information on this page.






    share|improve this answer






























      1














      There are already great answers, but I also found out about the interrupt functionality:



      const byte ledPin = 13;
      const byte interruptPin = 2;
      volatile byte state = LOW;

      void setup() {
      pinMode(ledPin, OUTPUT);
      pinMode(interruptPin, INPUT_PULLUP);
      attachInterrupt(digitalPinToInterrupt(interruptPin), blink, FALLING);
      }

      void loop() {
      digitalWrite(ledPin, state);
      }

      void blink() {
      state = !state;
      }


      some point:




      • no matter using interrupt or the methods above tho process will not achieve stable / deterministic result. The issue lies in the hardware of the push-button and there will be fluctuations which can be interpreted by the MCU. One way to alleviate is to use delay.

      • The


      • attachInterrupt has four modes LOW, Change, FALLING and RISING. The FALLING and RISING modes are the one to be used. the other two also lead to very unpredictable result.

      • Only pins 1 and 2 can be used for interrupts.

      • There is also the option to mix the two methods which you can see here, but I'm not sure if it will improve the stability.


      I used this video and information on this page.






      share|improve this answer




























        1












        1








        1







        There are already great answers, but I also found out about the interrupt functionality:



        const byte ledPin = 13;
        const byte interruptPin = 2;
        volatile byte state = LOW;

        void setup() {
        pinMode(ledPin, OUTPUT);
        pinMode(interruptPin, INPUT_PULLUP);
        attachInterrupt(digitalPinToInterrupt(interruptPin), blink, FALLING);
        }

        void loop() {
        digitalWrite(ledPin, state);
        }

        void blink() {
        state = !state;
        }


        some point:




        • no matter using interrupt or the methods above tho process will not achieve stable / deterministic result. The issue lies in the hardware of the push-button and there will be fluctuations which can be interpreted by the MCU. One way to alleviate is to use delay.

        • The


        • attachInterrupt has four modes LOW, Change, FALLING and RISING. The FALLING and RISING modes are the one to be used. the other two also lead to very unpredictable result.

        • Only pins 1 and 2 can be used for interrupts.

        • There is also the option to mix the two methods which you can see here, but I'm not sure if it will improve the stability.


        I used this video and information on this page.






        share|improve this answer















        There are already great answers, but I also found out about the interrupt functionality:



        const byte ledPin = 13;
        const byte interruptPin = 2;
        volatile byte state = LOW;

        void setup() {
        pinMode(ledPin, OUTPUT);
        pinMode(interruptPin, INPUT_PULLUP);
        attachInterrupt(digitalPinToInterrupt(interruptPin), blink, FALLING);
        }

        void loop() {
        digitalWrite(ledPin, state);
        }

        void blink() {
        state = !state;
        }


        some point:




        • no matter using interrupt or the methods above tho process will not achieve stable / deterministic result. The issue lies in the hardware of the push-button and there will be fluctuations which can be interpreted by the MCU. One way to alleviate is to use delay.

        • The


        • attachInterrupt has four modes LOW, Change, FALLING and RISING. The FALLING and RISING modes are the one to be used. the other two also lead to very unpredictable result.

        • Only pins 1 and 2 can be used for interrupts.

        • There is also the option to mix the two methods which you can see here, but I'm not sure if it will improve the stability.


        I used this video and information on this page.







        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited 2 days ago

























        answered 2 days ago









        FoadFoad

        1185




        1185























            0














            This is a comment (but could not use text alignment in a comment):



            Instead of



            if (flag){
            digitalWrite(ledPin13, LOW);
            } else {
            digitalWrite(ledPin13, HIGH);
            }


            You can use:



            digitalWrite(ledPin13, flag ? LOW : HIGH);


            (It is functionally 100% equal though).






            share|improve this answer



















            • 1





              Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

              – Michel Keijzers
              2 days ago






            • 1





              Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

              – Michel Keijzers
              2 days ago






            • 1





              I do not understand why they down voted you. I appreciate your support anyway.

              – Foad
              2 days ago






            • 1





              Probably because it should be a comment (but code alignment is only possible inside an answer).

              – Michel Keijzers
              2 days ago








            • 1





              @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

              – orithena
              yesterday
















            0














            This is a comment (but could not use text alignment in a comment):



            Instead of



            if (flag){
            digitalWrite(ledPin13, LOW);
            } else {
            digitalWrite(ledPin13, HIGH);
            }


            You can use:



            digitalWrite(ledPin13, flag ? LOW : HIGH);


            (It is functionally 100% equal though).






            share|improve this answer



















            • 1





              Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

              – Michel Keijzers
              2 days ago






            • 1





              Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

              – Michel Keijzers
              2 days ago






            • 1





              I do not understand why they down voted you. I appreciate your support anyway.

              – Foad
              2 days ago






            • 1





              Probably because it should be a comment (but code alignment is only possible inside an answer).

              – Michel Keijzers
              2 days ago








            • 1





              @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

              – orithena
              yesterday














            0












            0








            0







            This is a comment (but could not use text alignment in a comment):



            Instead of



            if (flag){
            digitalWrite(ledPin13, LOW);
            } else {
            digitalWrite(ledPin13, HIGH);
            }


            You can use:



            digitalWrite(ledPin13, flag ? LOW : HIGH);


            (It is functionally 100% equal though).






            share|improve this answer













            This is a comment (but could not use text alignment in a comment):



            Instead of



            if (flag){
            digitalWrite(ledPin13, LOW);
            } else {
            digitalWrite(ledPin13, HIGH);
            }


            You can use:



            digitalWrite(ledPin13, flag ? LOW : HIGH);


            (It is functionally 100% equal though).







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 2 days ago









            Michel KeijzersMichel Keijzers

            6,98751939




            6,98751939








            • 1





              Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

              – Michel Keijzers
              2 days ago






            • 1





              Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

              – Michel Keijzers
              2 days ago






            • 1





              I do not understand why they down voted you. I appreciate your support anyway.

              – Foad
              2 days ago






            • 1





              Probably because it should be a comment (but code alignment is only possible inside an answer).

              – Michel Keijzers
              2 days ago








            • 1





              @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

              – orithena
              yesterday














            • 1





              Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

              – Michel Keijzers
              2 days ago






            • 1





              Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

              – Michel Keijzers
              2 days ago






            • 1





              I do not understand why they down voted you. I appreciate your support anyway.

              – Foad
              2 days ago






            • 1





              Probably because it should be a comment (but code alignment is only possible inside an answer).

              – Michel Keijzers
              2 days ago








            • 1





              @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

              – orithena
              yesterday








            1




            1





            Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

            – Michel Keijzers
            2 days ago





            Actually the Arduino IDE is very similar to C++. The ternary operator is from the C language.

            – Michel Keijzers
            2 days ago




            1




            1





            Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

            – Michel Keijzers
            2 days ago





            Also several libraries are written in C++ (so you can use OO/classes); however some features are better to skip (like the Boost library if it works at all), because of dynamic memory management versus having only a few KB SRAM available.

            – Michel Keijzers
            2 days ago




            1




            1





            I do not understand why they down voted you. I appreciate your support anyway.

            – Foad
            2 days ago





            I do not understand why they down voted you. I appreciate your support anyway.

            – Foad
            2 days ago




            1




            1





            Probably because it should be a comment (but code alignment is only possible inside an answer).

            – Michel Keijzers
            2 days ago







            Probably because it should be a comment (but code alignment is only possible inside an answer).

            – Michel Keijzers
            2 days ago






            1




            1





            @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

            – orithena
            yesterday





            @Foad You could think of the Arduino sketch file as a part of a standard C/C++ file. Prior to compiling, the sketch is just inserted into the main file of a standard GCC build tree, included library files and hardware libraries are just copied next to it. Then gcc takes over; you could see its output if you enable verbose compiling in the Arduino IDE preferences.

            – orithena
            yesterday


















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