Help Getting Started - Simple DC Circuit

(I apologize for posting this basic circuit question. 25 years ago in
college I had to know E=IR etc. Just having problems getting started...)

I'm trying to "invent" a mechanical device. I've been having some alignment
problems with it and this afternoon it occured to me some simple electronics
would help a lot. But it has been many years since I've done anything more
complicated with electronics than change batteries in the household smoke
detectors. ;-) I'm looking at the Jameco web site, seeing if I can find
enough info to play with E=IR but there are just too many options &
choices...

I want to go to my neighborhood Radio Shack and buy
- 30 ea SPST NO switches
- 30 ea green LEDs
- 30 (?) ea resistors to limit current to the LEDs
- A circuit board to solder the LEDs & resistors to
- A battery case (e.g. 4 "D" cells) or 9v clip
I have an electronics soldering iron and plenty of wire.

The goal: When everything is lined up right on my mechanical device, all
the switches will be closed and all 30 LEDs will be glowing. Then I'll
unplug the battery, as the machine is ok once all the switches are closed.
(E.g., no long-term lighting requirement.)

How can I get started with this? For the battery which value to use, 1.5,
3, 6 or 9 volts? Does each LED need its own resistor or is one resistor
enough? (I don't care how bright the LEDs are so long as they are visible.)

Thanks.

-- Mark


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Relevant Pages

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