I am building the above to basically get 2 different cameras with different shutter lags to release at exactly the same time and ultimately share 1 external flash.

I have written the code and built the timer module, all I need now is a way to release the shutter of the camera. I need to connect ground to focus and then ground to shutter. I could use reed relays but they take 1.2ms to operate and also more voltage than I have - I want to use just 3v.

I came across a circuit using a 4N26 Optoisolator. I could drive this straight from a PIC output - I guess they will work @ 3v ?

If they will work at this voltage, is there a dual package equivelant that is readily available in the UK?

Cheers
Adam

 

Can you provide a link to the circuit you found?

hgmjr

 

Not really much of a circuit - just the idea really.
Scroll down to the large circuit on the 2nd link Basically just using the opto as they have but from the PIC outputs instead of the serial port.
There are several ways to do it I guess, transistors, relays etc but I think this would be the easiest and safest.

My camera needs Focus and Shutter connecting as in the first link:
http://www.covingtoninnovations.com/dslr/CanonRelease40D.html

Circuit for different camera - using the opto
http://www.beskeen.com/projects/dslr_serial/dslr_serial.shtml

Similar idea
http://www.electro-tech-online.com/micro-controllers/11363-using-4n26-optoisolator.html

Cheers
Adam

 

If you just put "Optoisolator" into the search field of a site like digikey.com (there are lots of others), it will show you a list of singles, duals, and quads (even some triples).

Depending on what you want to do with these, you might want to use a darlington version. The isolators isolate very well, but are often awful at CTR (Current Transfer Ratio). Darlington version are better at CTR but tend to be slower (but still fairly fast).

I can't know how available they would be locally.