Multiple photresistors

Projects Programming
1

Good afternoon, I am working on a project and I am trying to connect to photoresistors to the Arduino to read a time difference between when each resistor's voltage changes so I can calculate the velocity of a projectile. Any advice would be very helpful on how to do this. Thank you.

int lightPin = 0; //define a pin for Photo resistor
int threshold = 500;

void setup(){
Serial.begin(9600); //Begin serial communcation
pinMode(13, OUTPUT);

}

void loop(){
Serial.println(analogRead(lightPin));

if(analogRead(lightPin) > threshold ){
digitalWrite(13, HIGH);
Serial.println("high");
}else{
digitalWrite(13, LOW);
Serial.println("low");
}

delay(50);
}

2

get rid of delay

Add a variable that tells you if there was something detected on the previous iteration of the loop for each sensor

If the first sensor's "previous" variable and the current reading are different, save the current time.

If the second sensor's prevoius variable and its current reading are different, take the difference between the current time and the saved time, do some math on it to find velocity, and print it out

3

How fast do you expect it to be travling?
The code is a bit crude for your stated aim.