I just got an assortment of photocells from radio shack and there are 5 different sizes. How do I know which one to use? should I socket the photocell/led combo? They are not labeled at all. I also got the big 10mm leds in red 5000mcd and white 28500mcd!
nah, don't socket. What I would do is use a breadboard and test a few out.
Jacob
breadboard the whole circuit? I don't even really know what I am looking for or what are the good characteristics of an ldr.
Good point, the entire circuit might be a bit much. I'm not sure how to test them on a breadboard come to think of it...
But the thing i see is using a socket will make them a little bit less secure. LDR's depend on being in a reliably stationary position to the LED to be predictably useable. The sockets will add size and moveable parts to you build you don't necessarily want there. Unless you soldered the parts into the Sockets once they've been chosen of course...
Truthfully, I doubt there'll be any discernible difference between the LED's and LDR's you'll try.
Jacob
I would get some heat shrink tubing to make them one unit. this makes it more reliable to mechanical shock, and easier to test since much less ambient light will enter the LDR.
LDRs can have some difference depending on their light/dark response. I honestly don't know a lot about them, even thought that's a terrible excuse on my part. But, I have used many generic Radio Shack ones over the years and had decent enough results. So, I usually just grab whatever I've got in the bin.
The places where they are more critical are in vibes.