I always wanted to build simple drawers and tiny supply elevators that could open and close, (rise and decend) at the push of a button. Now I have several practical uses for a circuit like that, but I'm still stumped on how to wire one.

 

What I'd like to replicate is the drawer of a cd drive. Push a button, and the drawer extends and stops. Push THE SAME button, and it recedes back into its box.

 

What is the name for this kind of circuit, and can someone post or direct me to a schematic. There's no need to cover the mechanics of the belts and pulleys, and I'm working with D.C. motors.

 

Many, many thanks,

 

Ernie

Sounds like you're looking for something like this.

 

http://en.wikipedia.org/wiki/Motor_controller#Servo_controllers

 

Also of interest would be this page, linked from the above.

 

http://en.wikipedia.org/wiki/Servomechanism#Position_control

Hmmm,

I was hoping for a cheap schematic using switches and diodes. Am I dreaming?

 

E.

Not at all. But I would think you'd still need some kind of micro controller to detect positions and decide when the whole thing stops. I won't link commercial sites here, but you can probably find the controllers themselves for something like $20 or so, then make the whole construction from that.

 

https://www.google.com/search?q=schematics%20of%20a%20servo%20controller&aq=f&um=1&ie=UTF-8&hl=sv&tbm=isch&source=og&sa=N&tab=wi&ei=KpOfUYf0K4SI4ASCloHQAQ&biw=1093&bih=1071&sei=OpOfUdDyOMeE4ASpxIGICg

 

Perhaps it's possible doing it more from scratch, but that would be far beyond my knowledge unfortunately.

 

Another link I found and skimmed through, which might be of interest:

http://www.audiworld.com/tech/elec142.shtml