Fluid or Water Level Indicator

The Reed Relay based Float Switches are used in Automobiles and even corrosive and volatile fluids. This can also be used to indicate level of water or operate pumps. The reeds are hermetically sealed in glass, Like the Incandescent bulb. The signal switched by reed also should be a few mA or even uA. This makes is safe in Volatile fluids, where sparking can cause fires.

Water Level Indicator with Reed Relays

This is a way by which you can monitor the level of fluids like water in a tank. Based on data from the sensor you can control things like solenoids or motors as required or even turn on a buzzer, hooter or annunciator in a control panel.

Then you need to assemble a small circuit within the long plastic pipe. Many reed relays with a chain of resistors in series has to be inserted in the pipe. The resistor and the glass reed relays should be in different levels of the pipe where you need an alarm or indication. Seal the pipe hermetically at both ends with epoxy resin after taking out a shielded cable of just 2 wires + 1 ground shield.

When the fluid level changes, the float moves up or down with it, when the float moves over a section of pipe where the reed relay is mounted, the magnets on the float make the reed operate and the resistance of the sensor changes.