Spirits of Old-School Nerdery, lend me your power! From your cinderblocked halls, glowing with the green light of oscilloscope displays, I summon you! From your recumbent bikes, I summon you! I need your Ancient Skills of Electrical Engineering! Please comment this post!
Here are my challenges, O wise ones:
Stepping down DC Power from 18v to 12 and 3v:
The MacGuffin — the AM transmitter that broadcasts the Sekrit Code you need to sign up for Guerilla Drive-In updates — has three components, all of which go in a waterproof (and therefore poorly vented) plastic box:
- An AM transmitter (requires 18vdc),
- A Sony Sports Walkman (requires 3vdc. I think. Two AA batteries end-to-end. That’s 3vdc, right?) with a 6-minute endless loop tape in it, and
- A red radio-shack panel light on the front (claims to be 12vdc).
I want to power everything off of just ONE wall wart, which will live outside the box, and pass in the power through a jack mounted in the box (already done.) I own an 18vdc wall wart, a 12vdc wall wart, and a car adapter that can step 12vdc down to 3vdc. Could I power the transmitter on the 18v wall wart, and also step down the power to 3v for the sports walkman? How would I do that? Just by soldering some resistors into a small Radio Shack project box? Would that end up generating a lot of heat? When you live in a medium-sized town like West Chester, where could you go to get that done? Do you call a small mom-and-pop TV repair shop? How about the 12v light? If I give it 18v, will it explode, or will it just be a little brighter and live a little shorter? Helllllllp!
Attenuating speaker-level output
The 16MM projector has a quarter-inch jack on the front that is used to drive an auxiliary speaker. If I just use an adapter to adapt that to an eighth-inch stereo jack, then plug that into a transmitter, I’m assuming the signal is too… something. Powerful? Does anyone know how to, er… “attenuate” what’s coming out of that quarter-inch jack labeled “speaker”, and make it so it’s… good… for putting into the “audio in” RCA jack in the back of a transmitter? Here’s a picture of the speaker jack from the projector, if it helps any. Does anyone know how do to this, or know what dongle I should get?
Thank you, O Spirits! I will leave a basket of capacitors and a crimping tool under the candles for you.
UPDATE: O spirits, thank you for your replies! I will indeed look into buying voltage convertors from Tyco, since they seem to actually, er… convert the voltage, not just turn the extra voltage into heat in a resistor. Also, I’ll just be taking the wires that go to the battery box in the walkman and wiring the power into that, so the walkman is expecting 3V…?