Dc motor problem

It would be helpful if you posted your Arduino sketch.

It would be helpful if you posted your Arduino sketch.

Hi I tried to attach it as a file!! Copy and paste did not work!

What is the best way??

Gerhard

/*

* dc moto with h-bridge and 2 potentiometers and 2 buttons

* 1 button for forward at speed set by pot 1

* 2 button for bacward at speed set by pot 2

*/

int pot1 = 0;          // potentiometer to pin A0

int pot2 = 1;          // potentiometer to pin A1

int enable = 11;       // to enable on h bridge

int motorPin1 = 9;     // to In1 on h bridge

int motorPin2 = 10;    // to In2 on h bride

int redBut = 12;       // button to 12 pull-down

int greenBut =13;      // button to 13 pull-down

void setup()                    // run once, when the sketch starts

{

  Serial.begin(9600);           // set up Serial library at 9600 bps

  pinMode(pot1, INPUT);       

  pinMode(pot2,INPUT);

  pinMode(enable, OUTPUT);

  pinMode(motorPin1, OUTPUT);

  pinMode(motorPin2, OUTPUT);

  pinMode(greenBut , INPUT);

  pinMode(redBut , INPUT);

  digitalWrite (motorPin1 , LOW);

  digitalWrite (motorPin2 ,LOW);

  digitalWrite(enable ,LOW);

}

int getPot1() {

  int v;

  v = analogRead(pot1);

  v /= 4;

  v = max(v, 90);

  v = min(v, 255);

  return v;

}

int getPot2() {

  int w;

  w = analogRead(pot2);

  w /= 4;

  w = max(w, 90);

  w = min(w, 255);

  return w;

}

int motorFoward() {

  analogWrite(motorPin1, getPot1());

digitalWrite(enable,HIGH);

digitalWrite(motorPin2,LOW);

}

int motorBackward() {

  analogWrite(motorPin2, getPot2());

  digitalWrite(enable,HIGH);

  digitalWrite(motorPin1,LOW);

}

int allStop(){

  digitalWrite (motorPin1 , LOW);

  digitalWrite(motorPin2 , LOW);

  digitalWrite(enable ,LOW);

}

void loop()                     // run over and over again

{

  if (greenBut = HIGH){

  motorFoward();}

  else if (redBut = HIGH){

  motorBackward();}

  else{

  allStop();}

}

Don't have time to look through it at the moment, but to post it just add <code>....</code> within the html editor.

First: also write to 'Enable' in the setup. You've now only defined it, please make sure you also write a high or low, depending on your driver.

Second:

if (greenBut = HIGH){ Should be:  

if (greenBut == HIGH){, so with two 'is equal' signs after each other. Same for the red button. With one '=' it's an assignment, with two ('==') it's a comparison.

There might be more issues, but this will give you a start.

Another small thing: The max of AnalogRead is 1023. Dividing that by four gives a max of 255. So your statement v=min(v,255) is superfluous.

Hi Thanks Victor

1 Sorry I dont understand that part please explain a bit more

2 That I will change and then test again.  PS this worked in that nothing happens at startup - but now the motor does not turn at all - even when buttons are pressed.????

3 I may need to put a limit on the motor speed later so I put the code in and set to the max - then it should be easy to change later.  I have a LOT to learn still.

Thanks Gerhard

Hi Gerhard,

1) You've now just set enable as output, you haven't said which level it should have. It is now either high or low. Maybe it doesn't matter in your program, but it's good practice to tell what level an output has before going into the rest of your program

2) How have you wired your switches? If you put one leg to VCC, and the other to the input, your program should work, I guess. If you've connected one leg to GND and the other to the input pin, you should make the pin pullup (use internal pull up resistor):

  pinMode(greenBut , INPUT_PULLUP);

   pinMode(redBut , INPUT_PULLUP);

In that second case (one leg to GND), you have to check whether a pin is LOW when it is pressed (if (greenBut == LOW)  )

3) Ah, OK

Hi Victor

Will go and read up on the levels in the setup - I have just got that it is an output and to make it LOW so it doesn't start the motor before the button is pushed.  I need a programmers manual!!!

The buttons are connected one to 5V and one leg to pin with a 10K resistor to ground.

I think I am missing something else as I cant get the motor to turn at all now!!!!

Is there any books just on programming Arduino C??????

Gerhard

Hey Gerhard,

I can't see the error right now. Your code was right for the switches you have. You could try turning on&off the on-board LED to see whether you're getting in a part of the code at all (for example in 'Move forward').

Another suggestion would be to add a "delay(100)" at the end or beginning of your loop so you go through all actions at a human-comprehensible rate. Maybe you're just writing the PWM too fast, mbed (other dev kit) has this problem, I'm not sure about Arduino.

Regarding 'Arduino C': there's no Arduino C. It's just C++, but with a few handy functions to handle hardware. I'm afraid I can't guide you here, I know Drew Fustini wrote a book, and there's a plethora of online documentation...

Changed If (greenBut == HIGH);

to If (digitalRead(greenBut) ==HIGH);

Now it works

Thanks for help and sugestions

Gerhard

Hello Gerhard,

Thanks for the feedback. It was so obvious we all overlooked you have to call the DigitalRead on a pin to get the value.

Greetings,

Victor