Macwarrior
New Member
Hey there,
I'm trying to build a simple optical control for my camera's cable release. Because of the way the release is set up, all it has to do is close a circuit - no power or anything. Light detection is ludicrously easy; turns out most photoresistors will do the job with nothing else added.
However, I'd rather have it detect darkness, so that I can trigger it with a laser or similar beam being broken. I'm sure this is also an incredibly simple circuit that you have requests for all the time...but I'm a designer, not an engineer. . I've dabbled in electronics and built a few simple projects, but I've never had any formal training.
I think that something like is pretty close to what I'm looking for, except that I don't want any power running through the "buzzer" area for fear of blowing up my camera. AFAIK, a transistor to close the circuit is all that will be necessary.
I'm pretty sure that a PNP transistor is the only thing I'm looking for - they open the gate with low voltage (= dark photoresistor) on the base, right? - but I've never done enough work with transistors or ICs to know for sure. Perhaps a phototransistor connected to a PNP transistor would allow it to activate with no external power source?
Can anyone help me out?
Thanks a bunch.
MacW
I'm trying to build a simple optical control for my camera's cable release. Because of the way the release is set up, all it has to do is close a circuit - no power or anything. Light detection is ludicrously easy; turns out most photoresistors will do the job with nothing else added.
However, I'd rather have it detect darkness, so that I can trigger it with a laser or similar beam being broken. I'm sure this is also an incredibly simple circuit that you have requests for all the time...but I'm a designer, not an engineer. . I've dabbled in electronics and built a few simple projects, but I've never had any formal training.
I think that something like is pretty close to what I'm looking for, except that I don't want any power running through the "buzzer" area for fear of blowing up my camera. AFAIK, a transistor to close the circuit is all that will be necessary.
I'm pretty sure that a PNP transistor is the only thing I'm looking for - they open the gate with low voltage (= dark photoresistor) on the base, right? - but I've never done enough work with transistors or ICs to know for sure. Perhaps a phototransistor connected to a PNP transistor would allow it to activate with no external power source?
Can anyone help me out?
Thanks a bunch.
MacW