The Pneumatic Pop-Up Scare
The gold standard of startle props: a cylinder, a solenoid, and a sensor that launch a hidden figure upward the instant a guest steps too close.
Master
A full weekend
$200–$350
Materials
- ✦Pneumatic cylinder (12–24 in stroke)
- ✦Air solenoid valve
- ✦Air compressor + regulator
- ✦PIR or beam sensor
- ✦Prop controller / relay board
- ✦Steel or aluminum frame stock
Tools
- ▸Welder or heavy bolts
- ▸Wrenches
- ▸Wire strippers
- ▸Drill
The Build
- 01
Build the rising frame
Construct a hinged or telescoping armature the cylinder will drive. Counterbalance it so the return is fast and quiet.
- 02
Plumb the air
Connect compressor → regulator → solenoid → cylinder. Set pressure low at first and climb until the motion is sharp but controlled.
- 03
Wire the trigger
Feed the sensor into your prop controller, then the controller into the solenoid. Add a cool-down so it can't fire on the same guest twice.
- 04
Hide everything
Bury the frame in scene dressing so the only thing a guest sees is the figure — appearing from nowhere, on cue.
Safety First
Pneumatics move with real force. Fence the strike zone so no one can be in the prop's path, secure all air fittings to rated pressure, and add an emergency cutoff your actor can reach.