I have been taking my confetti/ paint cannon I have built to recent Maker Faires (Newcastle and Brighton), but hadn’t been able to run them at the event due to the resultant mess they would create, so had to be satisfied with video of them in action. I therefore set about working out a system that could feasibly be run at events.
I constructed an enclosure designed to be easily dismantled from 1/2” ply and other timber salvaged from a large packing case. It is largely held together with hinges and pin-hinges, a technique widely used for theatrical set. All pieces were designed so that they will fit in the back of the car for easy transport. I built a pair of porthole windows from MDF and scrap acrylic sheet to enable a view from the side, these are held on with bolts hidden with the plastic caps found on playground equipment. The whole lot was finished in paint from the mismatch section of the local DIY store.
The completed enclosure
The three cannons were built for the project, based around new industrial solvent weld PVC pipe and some unused 24V valves found in the scrapyard. A reservoir of around 1 litre was constructed by capping off a length of tube, with this mounted using surplus clips onto a length of scrap aluminium angle. The barrel is kept of a small diameter and fixed directly to the valve. A tee piece allows an air connection to be made to the unit. The whole assembly is mounted on an angle bracket with a handwheel and packed with nylon washers so that the cannon can be aimed. Three of the cannons are mounted on a front shelf, and set up so that they can only be aimed into the enclosure.
Cannons with solenoid valve used
An air manifold with regulator and shut off valve is used to distribute the compressed air to the cannons, and to allow them to be isolated.
The valves are controlled from a set of three large red buttons located remotely to the enclosure- these are powered via a key switch and dead man’s switch so that they cannot be accidently fired. A pair of strobe beacons is mounted on the top of the chamber which come on with the dead man’s switch to signal that firing is happening. All is run off a low voltage isolated supply for safety.
The Cannons being tested
In use, a sheet of paper (or any other object such as a t-shirt) is fixed to a removable board which is then hung in the enclosure. Using a syringe, the participant loads the three cannons with a small amount of paint, aims them where they want and then fires them remotely. The picture can then be retrieved and laid out to dryVideo of the cannon action can be seen in the Brighton Mini Maker Faire 2014 video BMMF