Help with automatic forward-reverse dc motor H-bridge

[rolord]

Hello,
I need some help on a project.
I have cannibalized an old CD drive and I want to use it for a gadget fun project where I need it to constantly open and close as long as its switched on.
I have removed all unneeded parts only left the opening/closing motor and the mechanics. Other than that its a 12v motor and that its very small I have no other infos on the motor.

Unfortunately I dont know much about electronics and cannot come up with a simple circuit that will do the trick.

From what I was able to find out myself is that I need something like a H-bridge.

I have searched other threads for a similar problem but unfortunately the attachments do not show. Also there were used much more refined versions using PWM to control the speed and timers to control delays between movements. Do I really need this? I can see that its probably not a good idea to switch polarity while the motor is turning full speed in one direction.

I have been able to wire a dpdt switch so that i can manually open and close it and confirm the motor is working but I want it to do this automatically.

I guess there is a simple solution to my problem but I am really a beginner and cant wrap my head around it.

If someone could draw me a schematic with all the needed pars connected It would be greatly appreciated.

Thanks a lot.

 

[dr pepper]

I wouldnt bother with that much complexity, you could do that with a relay and 2 push switches or microswitches, arrange the switches so that one makes when the sraw is open and the other when the draw is closed, the relay operates and latches on when opening and when open the switch is operated and the relay drops out closing the draw and restarting the cycle.
The draw open switch would be normally closed and the draw closed switch a normally open.
It would be simple still to just use the switch you allready have, cut aslot in the platic section of the draw and position the toggle switch insode it, make the slot the right length so that the switch is just made when the draw is fully open and just made when the draw is fully closed, the system will then oscillate nicely, without any electronics.