Hello.
My circuit is driving me 'round the bend, but it's probably a simple solution.
I am using a 3-pin IR Receiver to detect IR signals from my TV remote control. At this stage I am only interested in detecting a signal. I will be using it as an IR controlled on/off switch in conjunction with a flip-flop. The problem I am having is that, the circuit works fine, except that the IR Receiver sends a pulse when powering up the circuit. This is no good as I don't want any triggering until I send a signal with the remote. I have ommited the flip-flop from the schematic as the mis-behaviour of the IR persists in the simplified version shown here. The monostable 555 is being used as a quick and easy de-bounce and the 1N4004 is to drop the voltage as the IR Receiver(and flip-flop) requires 5V (IR Receiver gives TTL out). I would love to know how to supress or avoid that power-up pulse. I'm sure it's easy, I just dunno how
Cheers
Mike.

Datasheet: http://www.jaycar.co.nz/products_uploaded/ZD-1952.pdf

 

I would love to know how to supress or avoid that power-up pulse. I'm sure it's easy, I just dunno how

You can achieve that by holding the 555 in "reset" for a short time after power ON. It can be done via a RC circuit at the 555 reset input pin#4.

 

Thanks for that. I knew it was probably something simple with a capacitor but just didn't have enough knowledge to nut it out.
Much appreciated.

 

But does this modification solves your problem?

 

But does this modification solves your problem?

Yes, it works a treat. Thank you.