A while back, [Windell] from Evil Mad Scientist Laboratories wrote up an article for Make Magazine detailing how he built a one-ton, servo-controlled scissor jack for under $100. He dropped us a line to let us know that the project details have been released for free at Make Projects, so we stopped by to take a look.
The project starts out by pulling apart an electronic scissor jack to get access to the solder pads for the up and down buttons. Once wires are added there, a servo is the next victim. [Windell] recommends using an old servo with a busted motor, but you can use a good one just the same. The servo’s pots are replaced with 10 turn pots, and then wired up to a controller board, to which the jack is also connected. Then, to provide feedback to the servo, a string is looped around the top of the jack, which is used to turn the pots added in the previous step.
[Windell] says that the setup works quite well, though we imagine the duty cycle might be a bit short before adjustments are required. Regardless, it’s a quick way to get a heavy load lifted with servo precision.