I'm assuming that this is oil in the sump of an engine that might be=20 running? How hot does it get? My thought would be to use tiny bead thermistors that are=20 deliberately run very hot due to the amount of current being forced=20 through them, then measure the resistance change when they are=20 immersed in the liquid and the temperature drops. This certainly=20 works well with water at room temperature but I don't know how well=20 it will work with oil that is at the engine's operating temperature. dwayne At 10:39 AM 2/17/2015, Neil wrote: >I looking into making an oil-level sensor as a general indicator of oil >level. It does not need to be super accurate, and really just needs to >indicate a minimum of 5 levels -- too low, low-side of normal, average >normal, high normal, or too full. Space for the sensor is tight -- >approx 1" dia and about 6" to 8" deep. I've found this page, which >shows some general ways this is done... >http://www.machinerylubrication.com/Read/23921/oil-level-sensors-automotiv= e-industrial > >What I'm thinking is a small donut-shaped float around a 6" tube, with >magnets in the donut and reed or hall-effect sensors in the tube. Or >vice versa -- a tube with the sensors in the tube wall, and a magnetic >ball floating in the center. Any better (simpler) ideas? Or anyone >know if I can do this with some type of capacitive sensing? > >Cheers, --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .