Well, magnetism attracts things that are made of iron or steel. Electromagnets can be turned on or off with a switch. If you place a piece of steel in a way that stops the drawer from being opened, you can switch on an electromagnet which pulls the steel out of the slot so the drawer can be opened.
The electrical part is the easy part. It's the "hidden" part that is difficult.
Well, magnetism attracts things that are made of iron or steel. Electromagnets can be turned on or off with a switch. If you place a piece of steel in a way that stops the drawer from being opened, you can switch on an electromagnet which pulls the steel out of the slot so the drawer can be opened.
The electrical part is the easy part. It's the "hidden" part that is difficult.
A pulley system with a standard motor can also work.
A small reverseable DC motor and a DPDT relay to reverse it. Throw in 2 limit switches to "know" when its fully opened and fully closed, and you are mostly there.
Depending on the drawer size, and the distance of travel, a spring system could still be used to push the drawer open as the spool unwinds the "retract" string/cable
Well, magnetism attracts things that are made of iron or steel. Electromagnets can be turned on or off with a switch. If you place a piece of steel in a way that stops the drawer from being opened, you can switch on an electromagnet which pulls the steel out of the slot so the drawer can be opened.
The electrical part is the easy part. It's the "hidden" part that is difficult.
you could of course use a retractable cable and spring system. The advantage would be fast opening of the drawer if you use some kind of clutch to engage the reel when pulling the drawer into the closed position.
On the other hand you certainly don't want the contents of the drawer to be pushed forward when the drawer hits the mechanical stop (the same what happens if you hit a concrete wall with your car ).
The pinion gear method takes care of smooth movement in and out and omits one part with lots of wear and tear (spring), which must be almost as long as the travel of the drawer.
I was thinking along the lines of cutting an automotive V-belt and laying it down as the rack gear, affixing it to the bottom or side of the drawer, then using a geared motor, find a drive gear whos teeth fit the teeth on the v-belt. Wallah! 1 super sized cdrom tray
He did say a "Small" drawer thats why i said a CD rom.
As for the cog belt idea, well that was what i was saying with using an old bubble jet printer carriage drive, as they have a cog belt and small DC motor ( or stepper in real early models) with a cog pinion drive on them.
Old printers are every where and free, with lots of extra goodies like photo interupters, and photo encoders etc, i have used them for many projects.
I was thinking along the lines of cutting an automotive V-belt and laying it down as the rack gear, affixing it to the bottom or side of the drawer, then using a geared motor, find a drive gear whos teeth fit the teeth on the v-belt. Wallah! 1 super sized cdrom tray
Thats an awesome idea, nice and simple with minimal parts. So far this seems like it would work best. Now what do i use to time the motor so it only operate long enough for the drawer to open?
Thats an awesome idea, nice and simple with minimal parts. So far this seems like it would work best. Now what do i use to time the motor so it only operate long enough for the drawer to open?
Little switches that get tripped when the drawer is all the way out, and another for all the way closed.
Look up micro switches , and limit circuits.
They can open the relay coil to kill the motor when the drawer reaches the proper point. When you hit the "close" button, it will switch the DPDT relay and provide momentary power to get the drawer off of the limit switch. Then it will close automatically from that point. Stopping when it hits the "closed" limit-switch.