What kind of switch am I looking for?

Please help me out by telling me what I need to look for, or whether or not it exists simply. Thanks

I want a switch that when I push it, it goes from the first throw to the second, but when the power goes off, it'll go back to the first throw.

The application is an idea I want to make for a small car light. There would be two switches, an on/off, then this switch, which would default to a row of red LEDs but when you hit it would go to a row of white LEDs. Then when you turn the power switch off, next time you turn it on, it would light up the reds.

I racked my brain to find an example, and the best I could come up with is from a camping headlamp. You press it deep and it turns on, then you half press and it'll switch to a dimmer setting. But it'll always start at the first setting. Maybe I should just get a cheap headlamp and cannibalize the switch, but I think that'd be wasteful (and probably not so cheap).

Make sense? Thanks in advance for any ideas. This is my first attempt at synthesizing something, and I've been wanting this for awhile.

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caarntedd6 years ago
It could be done with a momentary pushbutton, and a standard 12v automotive relay with one set of NO contacts and one set of NC contacts.
simboka (author)  caarntedd6 years ago
12V? Is that the required voltage? I was planning on this being battery powered with 2xAAA or 2xAA (for size considerations).
You say you want to make a car light, why not use the 12v supply from the car? If you want to use a relay to do this, then it must be compatible with your power source. 12v automotive relays are easy to get.
A push button start/stop switch for machinery should do the job, but you will probably want to replace the red/green buttons.

Actually, I just had a look around, and some juke boxes have these switches on the selection panel, complete with illumination.
framistan6 years ago
You will want to use a RELAY for that. Just get a relay that has several sets of contacts. Use one set of contacts to HOLD the relay closed. Then when you turn OFF the main switch.... the relay turns OFF and you are back to BEGINNING mode when the circuit is again activated. Using a relay, you can do this. If you have trouble figuring it out, i will post a diagram for you if you ask.