Mulitple Phase level sensor

Discussion in 'The Projects Forum' started by beaster, Jun 7, 2010.

  1. beaster

    Thread Starter New Member

    Jun 7, 2010
    Hi all,

    I was hoping to get some advice on how to construct a probe that will indicate when I encounter a phase change in a two phase liquid system. ie I have a glass full of oil and water and if I lower a probe down through the liquid I would like a light to indicate when I move from the oil to the water. The top liquid has almost no resistance (somewhere between 10^-5 ohm and 10^-6 ohm) and the denser liquid is .23 ohm to .55 ohm. The reason for the resistance difference is that I want to use this over a wide temperature range.

    I was wondering how I wold go about doing this ?? Could I apply a voltage accross the probe and then just store the current value somehow. Then use some logic to trigger a relay if that current value increases significantly ?
    Or does someone have any other method of tackling this problem ??
    I really don't know much about circuits beyond what I learned in 1st year university physics - (I seem to remember some about a guy named Kirchoff and his law)
    Any help would be GREATLY appreciated !