I am building a cheap water level sensor for hydro-test purposes, using a piezo buzzer and a 9 volt battery, wit the circuit completion done by water shorting out the bare wires. The buzzer is loud enough on the 9 volts, but the resistance of the water does not give me onough power to hear it very well. What voltage ( DC ) should I use? or is it an amperage problem ? Any help would be appreciated.
Water Level Sensor
Aug 08, 2004
6 Replies
Adding a transistor or FET amplifier / switch stage should work and still remain simple.
You are trying to use the sensor to drive the end device. You need to have an amplifier in between. A very simple transistor circuit will do the trick. Do NOT try to fix this problem by boosting voltage. Sooner or later somebody is going to get hurt.
Walter.
A simple way is to put your bare wires on the jaws of a clothespin, with an aspirin in between. Water hits, aspirin melts, clothespin closes, circuit is made.
That is brilliant. The true meaning of K.I.S.S.
Popular Mechanics or Popular Science ca. 196x... nice trick.
Best regards, Spehro Pefhany
I did not mean to claim it was an original idea. If I had any idea where I read it, I would be glad to give credit where due, but I just can't remember.
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