LM317T Voltage Regulator with Pass Transistor

My first "serious" project (besides playing with lights, as my friend Alan put it) is almost done. This is going to be a configurable remote for my Canon EOS 350D / Digital Rebel XT (and possibly for all the cameras of that series). The shutter is closed when two lines of the 2.5 mm stereo jack are shorted; this is achieved by using the relay. My remote has two modes of operation, chosen through a simple deviator used as a switch: time lapse and bulb. In time lapse mode, it counts down to the specified interval and quickly closes the relay switch to fire the camera's shutter, then starts counting again. In bulb mode, it immediately closes the relay switch and starts counting; when the counter reaches zero, the relay switch is opened (the camera's shutter opens too) and it goes back to idle mode. The interval is defined in seconds and can be any multiple of 5 between 5 and 995 (that's over 16 and half minutes, and it's close to the camera B mode limit of 999 seconds). It is changed through two buttons (UP and DOWN). The third button, ENABLE, starts or stops the counter; I had originally thought about using a deviator switch for it, but I realized that the counter should have been stoppable by software too, therefore a push-button proved most useful for that. In this video, the shutter control is replaced by a green LED as I currently lack a wire long enough for my needs. I will solder it to the connector tomorrow, and test it in the field. Hopefully my camera won't be ...



http://www.youtube.com/watch?v=I2Ncbk7wGo4&hl=en