Sensor Analog

Water Level Sensor Module

A water level sensor module uses exposed conductive traces to produce a changing signal as more of the probe touches water.

Part images

Water level sensor. Interleaved traces change resistance as water bridges them. Image source: SunFounder Pico 2 W Starter Kit documentation, Components section, © 2026 SunFounder.

What it is

A water level sensor module uses exposed conductive traces to produce a changing signal as more of the probe touches water.

How students use it

Students use it for tank-level demos, plant watering ideas, pump cutoff concepts, and analog threshold practice.

Pins and power

Typical module pins are signal, power, and ground. Verify labels on the actual module.

Power only while taking readings when possible. Use Pico-safe voltage and keep electronics away from spills.

SunFounder describes ten exposed copper traces arranged as five power traces and five sensor traces; water bridges traces and changes resistance.

Voltage and safety

Keep water experiments low-voltage. Never put mains power near water or the sensor.

Only the trace area should touch water. Keep the Pico, USB cable, and computer dry. Power off before changing wet wiring.

Module internals

Main component: Conductive water-level probe board with exposed interleaved copper traces.

Interleaved copper traces, signal-conditioning traces, power indicator LED, header pins, and PCB substrate.

Datasheet notes

SunFounder warns the whole sensor must not be submerged and recommends powering it only while taking readings to reduce corrosion.

Common libraries

Use machine.ADC for analog level readings. Power-gate the sensor with a GPIO or transistor only when lessons are designed for that.

Common mistakes

Submerging the whole board, leaving it powered continuously in wet/humid conditions, expecting precise depth measurements, and spilling water onto the Pico or breadboard.