I'm working on a project that utilizes pneumatics, and I'd like some info on pressure sensors. Basically I'm attempting to build an air chamber out of PVC pipe that I'll pressurize with a small emergency-type compressor to only a few PSI (maybe 4 or 5). Ultimately I'll dump the air using a valve of some kind (maybe a sprinkler system valve). I'd like to be able to turn off the compressor once the chamber has reached it's ideal pressure (probably with a relay or some such device), and then recharge after I've dumped the air.
Anyone know where I can find a device that'll let me measure the pressure with perhaps a change in resistance or something? I've been using Google to search for "Pressure Sensor" and such things, but all the devices I'm seeing cost in the 20-100 dollar range. Surely there's cheaper alternatives out there. I could probably time the charging to get results that are ballpark, but I'd like more precise PSI (resolution to around .1 PSI if possible).
Has anyone done anything like this before, and can you point me to a good source for parts?
Thanks, Aneal K.