Final touches to laser trigger for flash

Hi

I used this project for glacial wanderer to start me off:

http://www.glacialwanderer.com/hobbyrobotics/?p=11

The code is pretty much the same. I am currently using the laser trigger. I made a few changes:

  1. I used a MOC3023 Optoisolator, here is the datasheet : http://www.mantech.co.za/datasheets/products/MOC302X.pdf
  2. I removed a flash from a Fuji disposable camera, external flashes from Nikon/Canon are too expensive and I am a student.
  3. I added a RGB LED that turns green when the laser is inline, and red when it is not (this is just used while setting everything up, and to make sure that the thresholds are the right value before connecting the flash).

The problem that I am having is that the flash does not trigger every time, only every 5th - 7th time the laser is interrupted/Serial Moniter prints "Flash Triggered" even when the drops are distanced far apart. While the trigger can still be used I would like to have this perfected before I move on. Any ideas about what the problem is?

flash does not trigger every time... even when the drops are distanced far apart

How far apart is "far apart"? Are you sure you are leaving enough time for the flash to recharge?

Also, are you sure you have solid and reliable electrical connections in your flash-triggering circuit?

Yes, I wait for the LED connect to the flash to light up completely. I’ve tested the circuit using the LED in place of the flash and it works perfectly, the flash I’ve tested by triggering it manually (touching the cables together). The only part I’m not certain about the battery that charges the capacitor for the flash unit, it sometimes comes loose. Would that make a difference? Even if the capacitor is charged?