Linear actuators are very expensive, at least the ones I have seen. The price is starting to come down slowly. Now , having said that:

One man built a robot called Bar2D2 which was a robot Bar. It served drinks. It had to get the drinks from the bottom tier to the top one. So, he used a linear actuator. The acuator was nothing more than a 12dc electric caulking gun with rack and pinion. It was really more ecconomical than the linear actuators that you see in the robot dealerships.

What length of movement do you need?

Hey guys I.noticed you are interested in linear actuators. They are fairly simple to make for 1/10 price to buy a premade one with similar stroke and power. I'm actually thinking.of using one on each arm just for elbow movement so that I have plenty of torque in a limited space. I can draw up how they work , hardware you gotta have ect. In car customization we made our own actuators because they start at like 200 and go up..

Please do Explain.

Now I don't know what size you need but the principal and parts are the same. First you get a cheap handheld electric screw driver or drill , take it apart. You go to Lowe's and pick out a threaded rod that will slide into the chuck on that motor you robbed from the drill. Cut down the threaded rod to just a little longer that your max stroke. Pick up nuts that match that thread on your rod. Now get tubing of your choice , I prefer PVC pipe but you can use copper or aluminum. Either solder or epoxy the nut to.the end of the tube. Grease up.that rod with lithium grease because you want this to actuate smooth. Now thread on the nut to the rod and cut of the other end of your tube a little longer thanthe threaded rod and you can drill holes in the end to connect the tube to the desired part you need to actuate forward or back. Basic parts list - motor with torque (drills work great) , threaded rod , a nut , a tube slightly larger diameter of your threaded rod , adhesive epoxy or solder.

Operation- the motor is mounted stationary , usually a worm gear clamp or two works well. And ofcourse the end of the actuator there are drilled holes to attach your mount. And long as both ends are secure the tube won't just spin in place. when the motor turns right the threads push the nut and rod away , when it turns left the threads pull on the nut and tub towards the motor.

Josh! That is a Great idea.

It's great if you need something simple and small that can handle several pounds. , take in mine faster rpm of motor and smaller diameter threaded rod means your actuator will move faster. I was thinking of using it to actuate the elbow joint on.my omni so it could have good holding power (because linear actuators don't give at all till power is applied)

You can use the glue stick method

Hi Ben

This is the actuator iv made for Aegis . It will lift 20 pounds with no problem. Maybe you could make a smaller one .

Sorry for the crappy pic will post a better one and instuctions soon.

Steve_C .

John,

Which leads did you tap off inside the servo. I understand it is the free rotating servo, and I have gutted plenty for model purposes (makes great radar motors on boats!), but I assume you use the signals to stop the servo when it reaches the extents of the pot movement.

Can you clarify a bit more?

Thanks!

I just found the link to the video and thought it might come in handy. Sorry, can't help you further