Complete Stand-Alone Air Powered Potato Cannon

I have fond memories of building potato cannons out of PVC pipe and fittings with my childhood friends. We used Right Guard spray deodorant (because it was the cheapest thing at the drug store) as a propellant and a a sparking lantern lighter as an ignition source. Those contained explosions that launched those potatoes off into the woods always made me nervous that the PVC may explode throwing sharp shrapnel everywhere. I had seen designs for air cannons that were much more safe and controlled but they required an air compressor and that was definitely not in our teenage budgets. Recently I was disassembling a car jumpstart battery/compressor combo unit to salvage parts and saw that the compressor hardware was actually quite small. It also including an inline pressure gauge as an added bonus. The idea quickly came to me — what if I strapped this thing to a potato cannon and had an all in one air cannon that didn’t require an air compressor and could run off just a LiPo battery?

I gathered the following supplies from Amazon, stopped by the hardware store for some PVC parts, and scrounged up some switches, wire, and zip ties I had laying around and started the build. The design uses a sprinkler valve to electronically release all of the compressed air, launching a potato or anything else that fits snuggly in the barrel. With the click of one switch, the compressor would kick on and fill up the air reservoir. Once full to the desired PSI, a click of a second switch would release the air, launching the potato hundreds of feet.

• 5200mAh 11.1V 50C 3S LiPo Battery

• XT60 Connectors

• Orbit 1-Inch NPT Jar Top Valve 57461

• Tubeless Tire Valve Stems

I had an old jump starter battery/compressor laying around. The battery would no longer hold a charge so I decided to strip it down for parts. As I was disassembling it I thought, this would be pretty awesome if I strapped it to a potato cannon. For reference, this is the model I had on hand.

After isolating the compressor and pressure gauge, I cut some thin plywood to cover up the exposed side. I used some of the case screws to fix the wood to the compressor assembly. I cut the extra screw lengths off with a Dremel. I also drilled some holes for zip tie mounts.

To connect the air compressor to the air cannon, I bought some tubeless valve stems to install in the 2" PVC end cap. I didn't have to use any glue as the rubber gasket provided a good enough seal.

The next step was creating the cannon out of PVC parts. All joints were glued except the threaded connections to the sprinkler valve. I 3D printed a switch housing, a battery holder, and a ramrod holder as well. One switch turns on the compressor and the other opens the sprinkler valve, firing the cannon. I did end up having to change the solenoid to a lower voltage battery operated solenoid. This is the replacement. It was very simple, just unscrew the old one and screw in the new one.