I am trying to use this photogate with my Arduino Pro Mini (5V.) I am having no luck getting any readings from it.

I measured the voltage across the emitter and got 4.5V, which should be enough to power the LED so I think the issue might be on the receiver side. I have tried using an external power supply up to 12V to power the receiver with some more juice (no difference.) I have the output pin hooked up to a multimeter and am consistently getting 0.1mV. I've tried this same setup with a different photogate and had no issues.

Here's my code if it's helpful at all:

    const int sensIn =A0;
const int ledPin = 13;
const int green = 7;
int value;

void setup() { 
  Serial.begin(9600);
//  pinMode(red, OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(sensIn, INPUT);
  pinMode(ledPin, OUTPUT);
}

void loop() {  
  digitalWrite(ledPin, HIGH);
  delayMicroseconds(500);
  value=analogRead(sensIn);
  Serial.println(value);
     delayMicroseconds(500);
  digitalWrite(ledPin, LOW);
  delayMicroseconds(500);
  if(value==0){
    digitalWrite(green, LOW);
  }
  else{
    digitalWrite(green, HIGH);
  }
}

Here's a picture of the breadboard: