Help Arduino DC Motors linked to levers to send Serial port a position

Other Hardware Motors, Mechanics, Power and CNC
1

Hello,

I face a problem using 3 DC motors connected mechanically to 3 levers. My code (see below) is correct but I can't find a solution to send the last position of each lever (angular position). In fact, I detect which of the 3 levers has moved and then I want to send a letter corresponding to the motor which has moved (F, G or H) with the last position at the end of the movement of the lever. Currently, I send various positions with a delay of 200ms (the positions during the movement of the lever), could you modify my code to get the letter and the last position of the lever ? Or a strategy to detect that the lever has finished its movement. I have tried different strategies but without success.

// Libraries
#include <AFMotor.h>

// Motor object
AF_DCMotor motor1(1);  // Assuming you have connected the motor 1 to motor port 1
AF_DCMotor motor2(2);  // Assuming you have connected the motor 2 to motor port 2
AF_DCMotor motor3(3);  // Assuming you have connected the motor 3 to motor port 3

// Potentiometer pin
const int potPinM1 = A0;
const int potPinM2 = A1;
const int potPinM3 = A2;


// Variables
//int potValue;
int potValueM1;
int potValueM2;
int potValueM3;
int potValueM4;
int potValueM1_init;
int potValueM2_init;
int potValueM3_init;
int potValueM4_init;
int prevMotor1Position = 10000; //10000 never reached
int prevMotor2Position = 10000; //10000 never reached
int prevMotor3Position = 10000; //10000 never reached
int targetPosition1;
int targetPosition2;
int targetPosition3;
int targetPosition4;
int currentPosition1;
int currentPosition2;
int currentPosition3;
int currentPosition4;
int threshold=0;
int MatLabMode;


void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Set initial target position and current position
  targetPosition1 = 40;
  targetPosition2 = 40;
  targetPosition3 = 40;

  potValueM1 = 0;
  potValueM2 = 0;
  potValueM3 = 0;


  potValueM1_init = analogRead(potPinM1);
  potValueM2_init = analogRead(potPinM2);
  potValueM3_init = analogRead(potPinM3);

  // Set up motor driver
  motor1.setSpeed(255);  // Set a constant maximum speed for the motor 1
  motor2.setSpeed(255);  // Set a constant maximum speed for the motor 2
  motor3.setSpeed(255);  // Set a constant maximum speed for the motor 3

  // Set up potentiometer pin as input
  pinMode(potPinM1,INPUT);
  pinMode(potPinM2,INPUT);
  pinMode(potPinM3,INPUT);
}

void loop() {
  // Read potentiometer value (feedback)
  potValueM1 = analogRead(potPinM1);
  potValueM2 = analogRead(potPinM2);
  potValueM3 = analogRead(potPinM3);

  // Map potentiometer value to target position (0-180)
  currentPosition1 = map(potValueM1, 0, 1023, 0, 180);
  currentPosition2 = map(potValueM2, 0, 1023, 0, 180);
  currentPosition3 = map(potValueM3, 0, 1023, 0, 180);


  if (Mode == 1 ) // Master Level to move manually the 3 levers 
  {
    targetPosition1 = currentPosition1 ;
    targetPosition2 = currentPosition2 ; 
    targetPosition3 = currentPosition3 ; 
  }

  if (Mode == 2 ) // Lever 1 master
  {
    targetPosition1 = currentPosition1 ;
  }

   if (Mode == 3 ) // Lever 2 master 
  {
    targetPosition2 = currentPosition2 ;
  }

   if (Mode == 4 ) // Lever 3 master  
  {
    targetPosition3 = currentPosition3 ;
  }


      // Calculate the difference between current and target positions
  int positionError1 = targetPosition1 - currentPosition1;
  int positionError2 = targetPosition2 - currentPosition2;
  int positionError3 = targetPosition3 - currentPosition3;

    // Check the difference between the previous and current positions to detect movement
  int motor1Difference = abs(currentPosition1 - prevMotor1Position);
  int motor2Difference = abs(currentPosition2 - prevMotor2Position);
  int motor3Difference = abs(currentPosition3 - prevMotor3Position);

  // Determine the motor direction based on the position error
  if (positionError1 > threshold) {
    motor1.run(FORWARD);
  } else if (positionError1 < -threshold) {
    motor1.run(BACKWARD);
  } else {
    motor1.run(RELEASE);
  }

  if (positionError2 > threshold) {
    motor2.run(FORWARD);
  } else if (positionError2 < -threshold) {
    motor2.run(BACKWARD);
  } else {
    motor2.run(RELEASE);
  }

  if (positionError3 > threshold) {
    motor3.run(FORWARD);
  } else if (positionError3 < -threshold) {
    motor3.run(BACKWARD);
  } else {
    motor3.run(RELEASE);
  }



  if (Mode == 1) // Master level 
  {
    if ((prevMotor1Position != 10000) && (motor1Difference > 2))
    {
        Serial.print("F,");
        Serial.println(currentPosition1);
        delay(200);
    }

    if ((prevMotor2Position != 10000) && (motor2Difference > 2))
    {
        Serial.print("G,");
        Serial.println(currentPosition2);
        delay(200);
    }

    if ((prevMotor3Position != 10000) && (motor3Difference > 2))
    {
        Serial.print("H,");
        Serial.println(currentPosition3);
        delay(200);
    }
    prevMotor1Position = currentPosition1;
    prevMotor2Position = currentPosition2;
    prevMotor3Position = currentPosition3;
  }


  // Add a delay if needed
  delay(20);  // Adjust the delay time as necessary
}
2

Welcome to the forum

Each time you read the position compare it with the previous position. If it has not changed then the lever has not moved

3

Thank you, yes I compare the current position with the previous position in the variables motor1Difference, motor2Difference and motor3Difference. I use it to detect a movement on one of the 3 levers. But how could I modify my code to compare the previous and the current value telling that when motor1difference = 0 Arduino has to send the position. To sum up , I detect a movement using motor1difference > 2 (threshold to be sure that lever has moved), and I want to get the final position when motor1difference = 0

4 
if (abs(currentPosition - previousPosition) == 0)
{
  //do what you need when the lever has not moved
}
else
{
  previousPosition = currentPosition;  //remember the position for the next check
}
5

Ok but I want to send the position only if the lever has been moved before and at the end of the movement. How can I merge the detection and the condition (abs(currentPosition - previousPosition) == 0) ? Do I have to add a flag in the detection part to say that the lever has moved and how could I program it ?

6

Declare a boolean variable and use it to flag whether the lever moved last time you checked

Something like this

static bool movedLastTime = true;

if (abs(currentPosition - previousPosition) == 0 && movedLastTime == true)
{
    //do what you need when the lever has not moved
    movedLastTime = false;
}
else
{
    previousPosition = currentPosition;  //remember the position for the next checke
}
7

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