SparkFun Qwiic Soil Moisture Sensor

Keeping your plants perfectly watered shouldn't require a complex setup. The SparkFun Qwiic Soil Moisture Sensor is a straightforward, easy-to-use breakout board designed to measure soil moisture and similar materials. It operates on a simple principle: the two large exposed pads act as probes, functioning together as a variable resistor. The more water present in the soil, the better the conductivity between the pads. This results in a lower resistance and a higher analogue signal (SIG) output, giving you accurate data for your soil's hydration.

The Qwiic Advantage

If you're like us, you probably want the absolute fastest setup possible. This version features an integrated Qwiic connector, powered by an onboard ATtiny85 MCU that acts as an I²C gateway.

• Plug-and-Play I²C: Connect the sensor to your compatible development ecosystem without ever touching a soldering iron.
• Broken-Out Pins: If you haven't adopted the Qwiic ecosystem yet, or if you want to reprogram the MCU yourself, we have fully broken out the programming pins so you can easily interface using standard I²C or SPI protocols.
• I²C Jumper: If you plan to chain multiple Qwiic devices on the same bus, the board includes an easily accessible I²C jumper on the back that you can cut with a hobby knife to disable the pull-up resistors.

ENIG Finish

A notoriously common issue with traditional contact-based soil sensors is their short lifespan in continuously wet, muddy environments. To combat this corrosion and significantly extend the board's life, we have coated the PCB with a high-quality Electroless Nickel Immersion Gold (ENIG) finish. This gold plating provides a robust layer of protection against the elements, ensuring your automated garden, smart greenhouse, or desk planter stays monitored for much longer than standard tin-plated boards.

Be sure to check out our Hookup Guide for our tips on weatherproofing your sensor's electronics and a simple starter project to get you growing right away!

• Schematic
• Eagle Files
• Hookup Guide
• Qwiic Resource Page
• Libraries:
  • Arduino
  • Python / MicroPython / CircuitPython
• GitHub Hardware Repo