Need help with coding an Arduino uno/Adafruit motor shield v1 and PIR sensor

Projects Programming
1

I'm trying to get one stepper motor to run when PIR sensor senses motion using an Arduino Uno and Adafruit motor shield v1. I have tested the Adafruit motor shield/Arduino and can run the stepper motor without the PIR. And, I have tested the PIR with an LED and it works fine but I obviously have the code wrong for the combination. Any help would be appreciated. The board does nothing with my current code.

#include <AFMotor.h>

int pirPin = 8;

int motionStatus = 0;
int pirState = 0;

AF_Stepper Stepper1(200, 2);



void setup() {
  Serial.begin(9600);
  pinMode(pirPin, INPUT);
  delay(2000);

  Stepper1.step(200, FORWARD, INTERLEAVE);
  Stepper1.setSpeed(10);
}

void loop() {
  motionStatus = digitalRead(pirPin);

  if (motionStatus == HIGH) {

    if (pirState == LOW) {
      Serial.println("Motion Detected");
      pirState = HIGH;

      Stepper1.step(2000, FORWARD, INTERLEAVE);  // turn it on going forward
      delay(1000);

    } else {

      if (pirState == HIGH)
        ;
      Serial.println("Motion Ended");
      pirState = LOW;
    }
  }
}
2

When triggered, the PIR stays high for maybe five seconds, not letting the program flow outside this condition until the PIR goes low...

  if (motionStatus == HIGH) {

Maybe "set a flag" rather than hold the program in the if() conditional loop, then test the flag, and if the flag is set, rotate the motor.

3

That's an interesting idea. I understand what you are saying but I don't know how to implement "a flag" in the code. What does that look like? Thanks for taking the time to look at my problem!

4 
if (motionStatus == HIGH)
  flag = 1;

Your code treats motion as "it is happening" and pir as "it happened." See if you can move your motor on motion detected and not on pirstate.

5

That didn't fix it. I'm wondering if it needs to somehow say the stepper motor is the output. I can't find any examples of that with this motor shield. It just says something like this Stepper1.setSpeed(10); Stepper1.step(200, FORWARD, INTERLEAVE); Does that alone make it an output?

6

What didn't fix it?

7

This else is a condition of the second if() condition, but it should be a condition of the first if() condition. To see what I mean, format your code. The open brace of the } else { should line up with the first if() (not the second if()).

Your code (mis-aligned else):

  if (motionStatus == HIGH) {
    if (pirState == LOW) {
      Serial.println("Motion Detected");
      pirState = HIGH;
      Stepper1.step(2000, FORWARD, INTERLEAVE);
      delay(1000);
    // } // missing this close brace
    } else {

Properly aligned...

  if (digitalRead(inputPin) == HIGH) {
    if (pirState == LOW) {
      Serial.println("Motion detected!");
      pirState = HIGH;
    }
  } else {
8

YES! That is it. It is working properly. Thank you!

1 Like
9

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