Quote Originally Posted by wildbill View Post
Which of these solenoids should I get? 1" travel, continous is what i'm guessing.i'd like to keep it under $35 if possible.
I'd like 12v but I don't know how big of a 12v battery would be needed.
http://www.mcmaster.com/#electric-solenoids/=fr188h
They seem to list the power consumption in watts and offer two different voltage ratings. You could determine the current by dividing the watts by the volts; e.g., a 6 watt solenoid on 12 volts would draw 0.5 amps. That's a pretty significant current -- no transistor radio batteries! Probably C or D cells, or maybe a rechargeable sealed lead-acid gel cell battery, would be suitable candidates. I would be a bit concerned about the mechanical interface too. A really powerful solenoid with a long stroke could possibly damage the shutter. This might suggest some sort of spring or other stretchy element to separate the solenoid motion a bit from the shutter trigger. Or perhaps some adjustable stop could be used. Those old mechanical self timer accessories typically had a sort of telescoping fitting with lock ring adjustment to set the actuator stroke depth.

This could turn into quite an exercise -- though perhaps fun.