Simple Water Level Indicator
This simple water level indicator can be built with only few components, the circuit will indicate when the water in a container is full or reach the wire sensors level.
The circuit is using two simple wires as a sensor to sense the level of water, you can set the wire sensors on a desired level of the water in container where you want the indication. The is using an LED as a indicator which will become activated when the water touches to the wire sensors.
The mains component of the circuit is a 2N3904 transistor that is working as a switch in the circuit. With the help of 100K variable resistor we can set the desired sensitivity of the circuit to sense the water, this feature will be useful when you want to use the circuit for other liquids than water, or if your container is too far due to which you have to use long sensor wires. You can increase the sensor wires from few inches to several meters.
The power supply to the circuit is provided with a 9V battery, but you can also use any type of battery you have for example 6V, 12V, whether it will be a lead acid or liion or AAA or AA size cells.