Thread: reversable motor for monitor?

This looks like it might get me a little closer to what I want to do.
It will reverse the polarity, However I cant find a U.S. supplier.



Found here http://www.distel.co.uk/asps/details1.asp?ID=LE11

That looks like a straightforward DPDT (dual position dual terminal) relay. You can find those just about anywhere. Try radioshack, mouser, digikey, etc.

I'm still learning alot about electronics myself, so I'm afraid I'm not going to be able to whip out a schematic that does what you want, but here's some thoughts to consider:

You're either going to want a timer circuit or some shutoff switch so that the motors stop after the requisite amount of motion. The really schmancy way of doing it would be to detect the current spike when the motor stalls and shut it off then. That's how window auto-downs generally work, I believe. I have no idea how involved this would be. A timer would simply be set up to juice the motors for x amount of time. This can be done pretty easily with a 555 timer chip, which is probably the way I'd go (if only because I know how.)

Now you want it to change polarity depending on whether your ign went high or low. That relay would do it for you, but that alone is not an ideal solution because the relay would consume some power all the while you're driving. A solution here might be to use a transistor to only allow the ign current through during the duration of the motor movement, covered above.

Then there's actually telling the whole thing to go. You want a circuit that goes high when the ign makes a low->high or high->low transition. I think a flip-flop chip might do that for you.

Lastly, you want a manual override. That'll probably be the least complicated part. Get yourself a (on)-off-(on) toggle or rocker switch. Make one side juice the relay and the other side not.

Check this site out for all sorts of different circuits - you can probably find all of the components to put the whole thing together. http://www.discovercircuits.com/

Hope that helped some. Like I said, I'm not a EE guy (software is my trade) so let that be a disclaimer. And maybe some more knowledgable guys around here will correct/improve upon my ideas.

Originally Posted by mushin

You're either going to want a timer circuit or some shutoff switch so that the motors stop after the requisite amount of motion.

I was thinking about a micro switch that would trip at the end of the travel, but i'm not an expert on this matters either.

Now i'm really getting stoked, check out these motors.
Hey, dont forget to come back to tell me how to wire this thing!

Originally Posted by mp3oplecarrier

I built a sliding metal cover for the ignition keyhole and radio slot on an open kit car. I used double pole relays wired to 'hold' on when tripped by a momentary pushbutton, one each for open and close, and then a microswitch at the end of each direction of travel to break the circuit... The first time I tested it the microswitch cut the power, but the inertia of the motor and all the various gears turning, meant half as pound of sheet metal mashed its way through my switches! I eventually managed to get it working with house alarm style reed switches and magnets. No pics I'm afraid, this was before the days of digital cameras!

This is the motor I was looking at. I dont think it's strong enough to break anything and its so tiny, it should fit easily into the space I have. I just have to find a way to step 12v down to 5v for it. Any ideas on the best way to do that?


Miniature Metal Gear Motor - 62 RPM

This small 1.14" (29mm) by 0.47" (12mm) by 0.39" (10mm) motor features a high quality, all-metal 196.6:1 gear train for smooth, quiet operation and a long operating life even under harsh conditions.

The motor delivers 62 RPM with 46 in-oz torque (3300 cm-gm) while drawing an efficent 120ma at 5v DC. It weighs 0.29 oz (8.2 gram). It has a 3mm diameter "D" shaped output shaft. The shaft can be mated with most 1/8" hole output devices including 1.25" Rubber Wheels. The faceplate contains two mounting holes threaded for M1.7 machine screws such as M1.7 x 4mm Machine Screw. Mfr. # NA4S