Arduino Auto Air Compressor / Pneumatic - US9116 Pressure Sensor / SANITAS SBM30
This... thing... uses the compressor, pressure sensor and solenoid vent from a Sanitas SBM-30 Blood Pressure monitor, controlled by an arduino it will maintain an arbitrary constant pressure in a resevoir.
The two transistors that drive the motor and solenoid are TIP 122.
The pressure sensor itself is a US9116-006 pressure sensor, the only information I could find was this: http://www.sensolution.co.kr/down/US9...
The LM386 op amp is very far from ideal, and totally arsed together, but it works just enough, and with correct bias set on the sensor from the 5k pot there's enough stability for a rough system.
The code is here:
[It works by sampling the value of the sensor while the motor is resting, then adds 100 units (1 unit = sampled voltage/1024 on arduino) - the entire thing is literally arsed together, but if you're trying to get off the ground with one of these pressure sensors it may get you started:]
https://drive.google.com/file/d/0By1U...
You'll have to pause the video for the plans.... :P