I have begun work on a new cannon, for the first time in several years. Here's some basic info:
The chamber has been glued together. It's double layer (pressure rated) SCH-40 throughout. Not pictured are the camlock couplings front and back.
The electronics enclosure. It will contain some basic electronics and three LiPo cells (18650).
The spark strip. I just cut a groove in some SDR-21 pipe and cemented in some bare wire with E6000 glue.
I've nailed this down pretty much. I've already prototyped this without the transistors (for the fan/igniter).
I put together the carry handle for the launcher. It's pretty standard for other launchers I've built, except instead of just a piezo BBQ sparker in the front, I have a safety and RGB ring-illuminated pushbutton. The "business end" comes off with four set screws, and the "bulkheads" the switches go through are simply friction fit into place for the moment. After a hundred or so shots without electrical problems I'll probably seal them in with some E6000.
So far so good... however, all 3 of the ignition circuits I ordered were duds... guess it's back to modifying stunguns. Just pretend there was a healthy zap towards the end of this video...
It always seems to go this way, doesn't it?
I am still (slowly) working on this cannon whenever I get the free time. The initial electronics design posted above turned out to be a little too bulky to fit into the enclosure I made, and my battery choice was also a little sketch.
The current design uses only switches still, but removes some of the other "fluff" of the older design and replaces the battery with a 4S (14.8V) LiPo pack with a charge/balance connector built into the enclosure, which has also been beefed up to be water resistant (along with the switches) along with the handle as well.