It has been... almost 7 months since my last update. There's something about summer that makes you want to put projects like this off! I have also been taking a class at the local university about space plasma physics, so that has taken up my time as well (and likely will slow me down until it's finished). Well, I have acquired both the valves (for fuel... propane... and oxidizer... compressed air), and tested them with compressed air. They both work great! They use different voltages, but that's not that bad (12V and 5V, I believe). I also have a manual ball valve, which I plan to use for the propane side for added safety.
I also acquired connectors for connecting a small, camping propane tank to my plumbing, but got the wrong gender attachment. I also have a pressure gauge, which I think works with propane as well.
What I need now is:
*the right gender propane tank attachment piece
*small propane tank
*spark generator (one of those coil-on-plug deals which just needs 12V and a TTL trigger or something like that and outputs a nice spark to my spark plug)
*a block of brass or something like that to machine the igniter out of
*perhaps some orifices to get the right flowrate for each side... possibly could just machine these directly into the brass block, but it'd be more difficult
*filters to put just upstream of the orifices to catch foreign debris and keep it from exploding (which it might anyway)
*5V and 12V power supplies with enough current for everything
Nice-to-have:
*maybe some sort of optoisolators to protect the arduino?
*maybe one or two extra, cheap arduino clones, like Sippino, so I have extras
*digital pressure sensor for the chamber, ideally pressure sensors for the chamber, one for oxidizer, one for fuel
*digital temperature probe for chamber
Eventually, I'd like to get some more cheap activated valves and make a mini cold-gas thruster system, with the little thrusters printed online. That'd be cool.
