I'm currently working on a camera shutter tester where i measure the time where photodiodes get hit by light.
The circuit is really simple right now.
The diode is connected to a digital pin and GND, the same digital pin is connected to 5v with a 100k resistor.
I'm working with digitalread as analogread is not fast enough
for my application.
The circuit keeps the digital pin high and the diode pulls the digital pin low when hit by light.
I can change the sensitivity with using a higher resistor like 3M but this way the measured time is not accurate any more and the time is displayed much longer than with the 100k resistor.
With the 100k resistor the measured times seems to be accurate but the the sensitivty is quiet low and i need really a lot of light to get the diodes triggered.
Is there any easy way to get the diodes really sensitiv with keeping the rise and fall times accurate so they stay precise ?
reading the diodes analog i can see that diodes only are pretty sensitiv, so my circuit to get a digital signal seems to be the problem.
does someone know a simple circuit to get a precise digital signal with a high sensitiv diode ?
I was thinking about getting a KY-037 microphone module and swapping the microphone with one of my diodes would this be a way ?
thanks for you replies upfront