DC Motor Control with a single button and H Bridge

Projects General Guidance
1

Hi all, I'm new to Arduino with no coding experience. I'm slowly working through a few tutorials to learn but I am still in the beginning phases, learning very basic code. I'm using an Arduino Uno board and for the past month, I have been fighting with a piece of code that I found online, that I modified to stop, start and change the direction of a dc motor with a single button. One press should start the motor, the second press should stop the motor. when the button is pressed again, it should start the motor in the opposite direction and another press should stop it again. The code which I will paste below, starts on the first press and stops on the second press as it should, the next press starts it again but sometimes in the opposite direction as it should but sometimes in the same direction as before which tells me that I have some error where it should change direction with every second press. Can you guys have a look at it and tell me where I'm going wrong. I would like to include a schematic but the system does not allow newbies to add attachments.

int IN1pin = 7;
int IN2pin = 8;
int ENApin = 9;
int motorSpeed;
int buttonPin = 3;
int motorState;
int lastButtonState;
int currentButtonState;

void setup() {
  // put your setup code here, to run once:
  pinMode(IN1pin, OUTPUT);
  pinMode(IN2pin, OUTPUT);
  pinMode(ENApin, OUTPUT);
  pinMode(buttonPin, INPUT);

  currentButtonState = digitalRead(buttonPin);
}

void loop() {
  // put your main code here, to run repeatedly:
  lastButtonState = currentButtonState;
  currentButtonState = digitalRead(buttonPin);

  if (lastButtonState == HIGH && currentButtonState == LOW) {

    //toggle state of motor
    if (motorState == LOW) {
      motorState = HIGH;
    } else {
      motorState = LOW;
    }

    //control motor according to toggled state
    digitalWrite(IN1pin, motorState);  //turns motor on or off, based on variable
    digitalWrite(IN2pin, LOW);
    analogWrite(ENApin, 255);
  }

  lastButtonState = currentButtonState;
  currentButtonState = digitalRead(buttonPin);

  if (lastButtonState == HIGH && currentButtonState == LOW) {

    //toggle state of motor
    if (motorState == LOW) {
      motorState = HIGH;
    } else {
      motorState = LOW;
    }

    //control motor according to toggled state
    digitalWrite(IN2pin, motorState);  //turns motor on or off, based on variable
    digitalWrite(IN1pin, LOW);
    analogWrite(ENApin, 255);
  }
}
2

That seems to be FOUR possible conditions, but you don't have that many in your code.

3

Please edit your post to add code tags.

As pointed out, there are four operational states. It would be a good idea to implement a 4 state "state machine" (look that up).

The press of the button would simply advance machine states cyclically 1->2->3->4->1 etc.

4

I recommend you get a copy of the Arduino Cookbook and skim it cover to cover and try any of the projects that interest you.

5

You want to make what is known as a “State Machine”

6

Hi, @goose_1709
Welcome to the forum.

This will show you how to post your code in a scrolling window.

Tom.... :smiley: :+1: :coffee: :australia:

7

Thank you, I am now looking at "State Machine" and how it works.

8

Thank You
I have edited my post from top to bottom, including the question that I asked, I will do it right from now.

9

UNless you also edited all the answers to your questions, the thread no makes no sense to anyone reading the thread. Why did you do that?

10

Thank you for the reply, I have edited my post, hope it looks better now, also busy reading all about how "State Machine" works. Perhaps once I understand it, I could solve my problem by starting with complete new code including the four state machine.

11

Please don't, other than add code tags. Editing content makes the thread difficult or even impossible for others to follow.