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I'd like to measure the oil pressure at the point where our domestic oil supply enters the house in order to gauge the tank level. For various reasons (mainly: the tank is in the middle of nowhere) it's not possible to use an ultrasonic measurement from the top of the tank.
So the next best step is to measure the oil pressure with the tank nearly empty, and full, and then interpolate to get a percentage of oil level through an Arduino or something similar, and set off an alarm from either low level or rapid drops (leak or theft).
Unfortunately, an oil pressure sensor seems to be a nightmare to get hold of. The only ones I can find are automotive and it's difficult to identify their measurement range. Has anyone come across this before? Needs to be able to measure from 0 to 75kPa.
You can use a car brake caliper resting under the tank, and measure the pressure in the brake fluid, or make a load cell. See here:
[url= http://www.nakka-rocketry.net/strainlc.html ]Load cell[/url]
The search term you're looking for is "Pressure transmitter" there's not much on ebay unfotunatelly. 75 Kpa seems high - thats 7.6m water gauge, and oil is less dense than water... search in Psi or mbar, that's what most people use... If you use an analogue trnasmitter then you'll need a trip amp to give you your alarm. Starts to get expensive.
Look out for a filter differential pressure mechanical pressure gauge with integrated low and high pressure limit switches. harder to find, but will solve your problem