Max photoResistor

Other Hardware Sensors
1

im controlling a Stepper with a photoResistor set, But if the values run to high it doesnt run the code like there is no difference between the sensors,,,, See if any on can see where my codeing is creatign the failer,, any suggestions would be greatly appreciated :slight_smile:

/* 
Thomas Wood
PhotoCell Controlled Stepper Motor Left and Right
Feb 15,2012
 */

#include <Stepper.h>

const int stepsPerRevolution = 200;  // Turns of the motor 
int inputPhotoLeft = 0; // photresistors pin
int inputPhotoRight = 1; // photresistors pin
int Left = 0; // Store readings from the photoresistors.
int Right = 0; // Store readings from the photoresistors.

int threshhold = 450; 
// this is here from reading the serial monitors valued to get a ruff Idea of value to set A
                      //And how dark you Want your motor to stop moving at 

int difSence = 20; // differenace tolarance between sensors

// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 8,9,10,11); 
void setup() {
  
  myStepper.setSpeed(150);
 
  Serial.begin(9600);
  
   pinMode(13, OUTPUT); //led doesnt need to be on
}
void loop() {
 Left = analogRead(inputPhotoLeft); // sets the photcells position left - right
 Right = analogRead(inputPhotoRight);
 //Lines for debugging ,analog display of sensor values
Serial.print(" Left \t");
Serial.print(Left);
Serial.print("  Right \t");
Serial.println(Right);
delay(1000);

(13 == LOW); 
if ((Left > threshhold) > (Right + difSence > threshhold ))
{
 
  Serial.print("clockwise \t");
  Serial.println(Left);
    myStepper.step(-stepsPerRevolution);
 
  
  }
if  ((Right > threshhold) > (Left + difSence > threshhold ))
{
  
  Serial.print("counterclockwise \t");
  Serial.println(Right);
   myStepper.step(stepsPerRevolution);
  
  
} 

if ((Left < threshhold) && (Right < threshhold))
{
  // this is to limit the after dark operation - 
  //no need in a plane,train,street light or automobil to make the panel move :)
  Serial.println("Lower threshhold Reached - hopefully we have stopped");
  Serial.print("Left Sensor \t");
  Serial.print(Left);
  Serial.print("   Right Sensor \t");
  Serial.println(Right);
digitalWrite(8,LOW);
digitalWrite(9,LOW);
digitalWrite(10,LOW);
digitalWrite(11,LOW);
delay(5000);
}
 
{
 // these are here to disengage the coils as not to hold ,and in turn over heat the motor
digitalWrite(8,LOW);
digitalWrite(9,LOW);
digitalWrite(10,LOW);
digitalWrite(11,LOW);

}
}
2 
(13 == LOW);

Doesn't do anything. Perhaps you meant "digitalWrite(13, LOW);" to turn the LED off?

if ((Left > threshhold) > (Right + difSence > threshhold ))

If Left is greater than threshold) is greater than (Right plus difSence is greater then threshold) make very little sense. I think you are trying to do too much in one comparison. (Left > threshold) results in a value that is 0 (false) or 1 (true). (Right + difSence > threshold ) similarly results in a 0 or 1. By comparing for the first one being greater then the second you are saying:

If (Left > threshold) is true (1) and (Right + difSence > threshold) is false (0).

I think what you intended was:

if (((Left > threshhold) || (Right > threshhold)) && (Left > Right + difSense))

That means: "If either is above the threshold and Left is far enough above Right to make a difference"

3

awsome more info to work with :slight_smile: time for new symble research, I'll see how this works and post my results :slight_smile:

4

also would you think with the possable error of syntax , would it make it when the photoresistors are at there max light the the left and right section not operate . or not operate from the threshold section ?

5 
if (((Left > threshhold) || (Right > threshhold)) && (Left > Right + difSense))

wouldn't that read - if left is greater than threshhold - or - right is greater than threshhold -- AND -- left greater than right plus differance...

would that make the code if eather sensor was above threshhold?

is this better

if (((Left > threshhold) && (Right > threshhold)) && (Left > Right + difSense))

wouldn't work smoother with the compairitor of && (and) to make sure both are below tolarance ?

6

ok - lol i was mistaken ,, || or works better ,, Thank you :slight_smile: