[ghostlland820]

Hi. With great advice, I'm making a gizmo to turn a tombstone into a Christmas package using a pneumatic cylinder and an up-and-down motion. https://www.halloweenforum.com/tutorials-and-step-by-step/197801-early-work-tombstone-flipper.html I'd like to have another prop--also changing from a tombstone to a Christmas present--using a spinning motion...like a turnable, with a tombstone on one side, then it spins 180 degrees, revealing the package on the other side. I thought it would be cool having different types of transitions as my house alternates between Christmas and Halloween decorations. Because I use Light-o-Rama controllers to synchronize to music, I'm limited to a design that has the prop in one position when power is applied and in the second position when the power is turned off. Suggestions for a 180 degree spin?

 

[sheepdiver]

Rotary pneumatic actuators are expensive - hundreds of dollars. You can try eBay but that's hit and miss. You could also use a standard cylinder with a rack and pinion set up. Look at the toothed belt they use for DIY 3D printers.

 

[ghostlland820]

Been thinking about this since first post. If I put a small platform on top of a lazy susan spinner, I might be able to use two cylinders to ping-pong the platform back and forth 180 degrees. The pistons on the cylinders would act like pool cues, smacking tabs on the underside of the platform to push it around. Maybe. An irrational challenge!

 

[bfjou812]

If you get a cylinder with a stroke that is long enough , you could just attach it to the lazy susan and use the extend / retract action to make it rotate 180°. Another way would to use a scissors mechanism and using a shorter stroke cylinder. Use a single acting cylinder and a solenoid that returns to no flow when powered off. When it is powered the cylinder extends, off the air is removed and the spring in the cylinder will retract the cylinder.

 

[Industen]

Wiper motor, attach it between to circles, add casters to make it spin easier, reduce voltage with a voltage adjuster for speed, add a voltage switcher so you can reverse the motor, put a timed relay on it to dial in the spin time.

I did this with my dancing ghost