Refer: Silicon Chip Magazine July 2007
This clever circuit illuminates a string of LEDs to indicate the water level in a rainwater tank. The more LEDs that illuminate, the higher the water level inside the tank. The input signal is provided by ten sensors that are connected to the indicator unit via light duty figure-8 cable. Kit supplied with machined case and screen printed PCB with overlay, and all electronic components.
> Requires: 20mm PVC hose/pipe (length required depending on depth of tank)
> Requires 12-18V AC or DC plugpack, 500mA