Not sure how to get If statement working.

Projects Programming
1

Hi--

I am running a DC motor controlled with a 10k potentiometer. I want to get the motor to only run when one of two push buttons/snap action switches are pushed. I have tried what other recommended by putting my potentiometer analog read and write into an if statement when the push button is low. However, I am not sure what I am doing wrong. When i upload my current code:

int analogInPin = A0;
int transistorPin = 3;
int sensorValue = 0;
int outputValue = 0;
int switch1 = 11;
int switch2 = 10;

void setup()

{

Serial.begin(9600);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(transistorPin, OUTPUT);
pinMode(switch1, INPUT_PULLUP);
pinMode(switch2, INPUT_PULLUP);

}

void loop()
{int val1 = digitalRead(switch1);
 int val2 = digitalRead(switch2);

 if (val1 == LOW)
 {
int sensorValue = analogRead(analogInPin)/4;
int outputValue = map(sensorValue, 0, 1023, 0, 255);
analogWrite(transistorPin, sensorValue);}
 
 if (val2 == LOW)
 {
int sensorValue = analogRead(analogInPin)/4;
int outputValue = map(sensorValue, 0, 1023, 0, 255);
analogWrite(transistorPin, sensorValue);}
}

it still only runs as if there is only a potentiometer. I am pretty sure everything is wired correctly.
Thanks!

2

davidjcshennn:
it still only runs as if there is only a potentiometer. I am pretty sure everything is wired correctly.
Thanks!

I suspect a wiring issue. Please provide a wiring diagram.

I would recommend forgetting about the motor and just try to detect the buttons being pressed by using a Serial.println debug statement.

3

Thanks for the response.

When I do Serial.Print (val) and push the buttons for both push buttons they are being detected fine in the serial monitor.

4

Do you realise you have 3 different variables each called sensorValue and another 3 called outputValue with different scopes?

Remove the 'int' from the ones in the if statement blocks. Then the global versions will be used everywhere.

Steve

5

Thanks for the response Steve.

So I removed int from all of the sensor value and output values and the circuit still wasn't working correctly.

I am not sure what I was doing but I got it to work by adding if statements and either switching the transistorPin or sensorValue in the analogWrite variables to 0 in the if statements. The else statements were my original if statements.

the circuit works as planned when either push button is pressed, the motor runs.

The code is attached here:

int analogInPin = A0;
int transistorPin = 3;
int sensorValue = 0;
int outputValue = 0;
int switch1 = 11;
int switch2 = 10;

void setup()

{

Serial.begin(9600);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(transistorPin, OUTPUT);
pinMode(switch1, INPUT_PULLUP);
pinMode(switch2, INPUT_PULLUP);

}

void loop()
{int val1 = digitalRead(switch1);
 int val2 = digitalRead(switch2);

 if (val1 == LOW)
 {
sensorValue = analogRead(analogInPin)/4;
outputValue = map(sensorValue, 0, 1023, 0, 255);
analogWrite(transistorPin, 0);}
else

{ 
sensorValue = analogRead(analogInPin)/4;
outputValue = map(sensorValue, 0, 1023, 0, 255);
analogWrite(transistorPin, sensorValue);}
 
 if (val2 == LOW)
 {
sensorValue = analogRead(analogInPin)/4;
outputValue = map(sensorValue, 0, 1023, 0, 255);
analogWrite(0, 0);}
else
{ 
sensorValue = analogRead(analogInPin)/4;
outputValue = map(sensorValue, 0, 1023, 0, 255);
analogWrite(transistorPin, sensorValue);}


if (sensorValue >= 160)

{
digitalWrite(8, HIGH);
digitalWrite(9, LOW);
}

else

{ 
digitalWrite(9, HIGH);
digitalWrite(8, LOW);
}
delay(10); 
}

Can someone please explain why this works? I can attach a complete circuit and wiring diagram. Thanks1

6

A circuit diagram might indeed help.

Your original code didn't do anything at all with pins 8 and 9 whatever they might be connected to. The current version looks like you're driving something like an L298 but you've never mentioned any such thing nor what the 'transistorPin' does.

Steve

7

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