[Rick Osgood] has been busy making more scaring gags for Halloween. This week he’s sharing great ideas for an air horn and pneumatic jumping skeleton, both actuated by 24 V sprinkler valves. These two new gags can easily be activated using [Rick’s] cardboard floor plate switch and three 9 V batteries cleverly snapped together in series for a 27 V supply (we can’t resist dropping in this link to a 2196 V supply from 9 V batteries just for fun).
The air horn construction is quite unique using a latex balloon strategically located as a reed valve for the air to vibrate over as it rushes out making a very loud honking sound. [Rick] then connected his manual bicycle pump to an air supply so that when an air valve is actuated the bicycle pump handle with a skeleton wired to it pops up. It then lowers back down via a bleed hole in the air line. Both the air horn and pneumatic pop-up skeleton seem simple to construct and his tests show them functioning perfectly.
Being the air storage chambers are small the re-trigger setup seems too repetitive to be practical for a continuous stream of Trick-Or-Treaters. Perhaps one could hide an air compressor with a long feed line to supply the gags? Plus, using an air compressor would come in handy for other scary blasts of air. Of course you would want to lower the compressor’s output regulator to safe levels so you don’t risk blowing apart your pop-up skeleton rig or any pipes.
Follow along after the break to see how to build these two great gags and get some tips from Mr. Safety.
Mr. Safety advice: Keep the pressure very low in PVC pipes because the pipes can shatter unexpectedly, more so in cold weather or as the pipes age or are exposed to sunlight. We have seen others wrap PVC air chambers in a roll or two of duct tape just in case the chamber fails. DO NOT apply pressure to any glued pipes until they have dried for at least 24 hours, the parts will come apart violently if you apply pressure before fully dry. Finally, when working with pressurized chambers you really have to know the safety limits of the materials you plan on putting under pressure. It is always best to use commercially constructed and welded air tanks with labeled pressure ratings. Metal chambers will be rated for much greater pressures even when constructed from metal threaded pipes. Don’t forget, in the US at least, you can get a cheap air regulator and 125 psi 11 gallon portable air tank at Harbor Freight for your scare gags.