It's great to see progress on the dual timer! I showed this to my son (age 12) and told him the goal was to repeatedly trigger two things simultaneously. He walked over to his computer and in a few minutes built it in Minecraft. So everybody is way ahead of me in circuitry.

Can you include two output ports (to the two cameras) on the board or will you split the signal with a Y cable?

I found that a 12v "23A" battery (for car remotes) fits perfectly into an "N-type" battery holder, providing the needed 12v to drive this circuit. Good thing; I was worried about finding a small 12v battery, and the actual "N" battery is only 1.3 volts.

$0.45 each for N battery holders: http://www.allelectronics.com/make-a-store/item/BH-50/N-CELL-BATTERY-HOLDER/1.html (also on digikey for ~$0.60)

$3.22 for 5 23A batteries: http://www.amazon.com/Alkaline-Batteries-GP-23AE-pack/dp/B002E4UWWQ/ref=sr_1_2?ie=UTF8&qid=1330437815&sr=8-2

Jeff, if you need to modify the circuit, look at the 555 calculator in my note on 555's.
http://publiclaboratory.org/notes/mathew/8-5-2011/adjustable-555-based-shutter-trigger-circuit

mistake! I had the two potentiometers backwards. It allows for "trigger down" time of 0.5-5 seconds, and "pause" time of 2.5-60 seconds. Perfect!!

I was considering building a 555 timer to trigger the IR control on my camera for mapping and was wondering if you had a schematic of what you used to trigger a button press. I've also considered a camera with chdk and might go that route, but I'd need another camera.

Hey Paul - check out Mathew's post, above -- but do you mean how do we wire it into the camera? I've been having trouble with that and you can read more here: http://publiclaboratory.org/notes/warren/3-1-2012/triggering-a495-buttonusb