want simple timeout circuit to pulse motor both ways

Thread Starter


Joined Feb 26, 2007
hi folks,
many thanks for reading this.

I'm after a simple circuit to produce a timed output on a relay to control a motor.
Using an old Cdrom drive, i want to lose all the electronics on the drive, and just use a push button to control the tray. I want either one or two buttons to first extend the tray, and then with either the same button or a 2nd button to retract the tray. Obvioulsy after loseing the main board it will have to be timed as not to go past the stops, and extend and retract the same distance within the confines of the drive.
Also i would like a LED based indicator, to say weather the tray is out or in.

I'm assuming it would possibly need 2 555 circuits, one outputing normal voltage to the motor to extend, and the other to apply reversed polarity to the dc motor to retract the tray.

also it would be really nice to have some other indicator LED via an opto sensor pair, to confirm the tray is extended or retracted.

The actual application for this circuit,is for my mates show car. He wants a show plate to be able to extend over his road legal plate. Ie in normal day to day use, the tray(and attached show plate) would be retracted into his car bumber, but on show days (and at macdonalds,lol) he can press a button on his dash, and his show plate with name on will extend over the orig road plate.

I very much apprieacte you time reading this, i only wished i payed more attention to basic electronics at uni...and possibly drank less beer at the time!




Joined May 16, 2005
CD Rom motors are three phase, requiring three stepped inputs. You'll need a controller. There's one on that board you were planning to throw away. I've never heard of someone running these motors backwards, but such should indeed be possible with sufficient tinkering. (Besisdes, the universe is chock-full of stuff I havn't heard of yet...)

A 555 will indeed work as a timer. I would use limit switches instead - vastly more stable over temperature changes.