Momentary relay driving circuit

[dine1967]

I bought the following chip from renton which is a preprogrammed PIC and works on sony protocol. I would like to use this for remote control of my preamp (volume up /down). The problem with the chip is that its output is not in pluse mode. ie. if I press the remote , the corresponding output goes from 0 to 1. It stays at 1 till I press the button again. Is there any circuit to drive relays momentarily ie it clicks everytime the output at PIC changes???? thanks
http://www.rentron.com/remote_control/IR-D14.htm

 

[thylantyr]

Many ways to skin a cat.

Edge triggered "one-shots".

Example; The cmos chip, the 4538 is a monostable multivibrator.
It's edge triggered, either rising or falling edge (you pick).
You select the output pulse duration. Connect the output
to a transistor to drive the relay.

http://www1.jaycar.com.au/images_uploaded/CD4538BC.PDF

 

[tiroth]

We need something triggered on both rising AND falling edge though, right? Two ORd 4538s (one rising, one falling) I guess. There has to be a more elegant solution though...

 

[thylantyr]

You get two one-shots in one IC package, use two
or'ing diodes to drive the relay transistor. Are you looking
for a single transistor solution, something simpler along
those lines?

 

[tiroth]

Ah...didn't think of that obvious solution. Nice!

 

[dine1967]

isn't this same as a standard IC555 timer in monostable mode. Iam new to this digital stuff .... please help

 

[thylantyr]

I think the 555 mono mode only triggers on negative edges.

 

[dine1967]

thanks, will order the IC and get cracking.