MIKROE Water Detect Click is used for detecting water and other electroconductive liquids. If the detection area is wet the output of Microchip's MCP606 CMOS op-amp will go positive, signaling the presence of liquid.

Water Detect Click can be used as a household flood alarm sensor, rain detector for smart buildings or for water tanks that act as a limit switch for a pump.

Water Detect Click works by comparing the voltage of two resistor dividers using the MCP606 comparator. The resistor divider (made of R2 and R3) is used as a voltage reference.

The MCP606 functions as a comparator on this Click board™.

The second divider is made of resistor R1 and the sensory area. When the sensory area is dry, it's resistance is near infinite, and the voltage applied to the inverting terminal of the comparator equals VCC.

Since the voltage of the reference divider connected to the non-inverting input is VCC/2, the output of the comparator is at zero voltage. Once the liquid is present at the sensory area, it's resistance drops and pulls the voltage on the inverting input of the comparator toward zero volts. Once this voltage falls below VCC/2, the comparator output swings toward VCC signaling the presence of liquid. The comparator output is tied to the INT pin on the mikroBUS™ header.

The water detection area is actually made of exposed conducting wires - simple but effective technology.

• Interface: GPIO
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V or 5V

• Schematic
• MCP606 Datasheet
• GitHub