Quote Originally Posted by Snap View Post
I would like a clean crisp voltage drop to give my pic a definite 0 or 5 volt difference. the problem is that if I am using an IR transistor (which I need to use) I can dim the led (with a comparitor circuit) by slowly covering the ir reciever (collector). My question is this.. can I create a circuit that will not dim a led ( meaning not a definat on or off) when I need a digital high or low signal... and I have already tried the 741 op amp comparitor. It dims the led as much as the straight transistor does. Could it be the resistors involved?
all I want is a way of telling the pic that I have a high (5 v)or low (<1.5v)signal. I think it is called hysteria,, Would a shmit trigger work?
Thank You For The Great Work
Snap
It would be helpful if you could describe the application more clearly.

What are you trying to make ?

If it is an IR receiver then using a dedicated IR Receiver module is by ar the most reliable.

If it is some form of beam break device then again I would use a dedicated IR receiver module but you would need to modulate the IR source with a 38kHz carrier.