Trying to build the Linear Actuator from Doom 3 project need advice

Has anyone tried to build Linear Actuator from a cdrom drive tray the way Crimson Sky did?

If so can you answer a couple of questions I have.

I know reversing the wires will reverse the motor but will I need some sort of limit swith to acomplish this?

If so how should it be wired up?


Any help will be appreciated

Charles

Do it with servos.

that should work.

Can't get enough travel with a servo that's why Crimson Sky did not use a servo on the blast door
he did however use one on the airlock doors.

Charles

Well, you could always just wire the motor so that the switch is momentary, make the motor about half speed, and just stop when it gets to the desired location.

I needed a similar setup once for a wooden media center I was building. I had a sliding door on the front which needed almost exactly the throw length of an opening cr-rom tray. What I did was actually leave the whole drive intact and use sleeved cables(made for RC airplanes to link servos to moving parts) as linkage from the opening drive to the sliding door. Then, you not only have a built in start stop point, you can plug it into the secondary IDE slot and write a real simple autoexec.bat file to cause it to open when windows boots, and windows automatically closes all drives when it shuts down. Don't know if this suits your design but I thought I'd throw it out there.
Jon

Try this stepping motor from jaycar Here

that is a pretty cool device, I may have to get one someday.

I used a special landing gear type servo for the linear actuator on the Airlock door. These servos have a higher degree of travel than the servos used for flaps and other moving parts of RC vehicles.