Using a leftover pendulum motor controller, Moog brushless motor scavenged from the Media Lab years ago, and gear pump from ebay to play with closed-loop pressure control. Pressure plotted on the computer screen (and shown on the gauge), pressure setpoint stepped up and down, and a needle valve used as a variable load.
Internals of the gear pump: Food-grade, stainless body with PEEK/CF gears and bushings:
