Ah, you just connected the photo diode and nothing else!
It is more normal to connect one end of the photo diode to the input and the other end to ground. Then add a pull up resistor from the input to +5V.
Ah, you just connected the photo diode and nothing else!
It is more normal to connect one end of the photo diode to the input and the other end to ground. Then add a pull up resistor from the input to +5V.