Tutorialintermediate
Capacitive Soil Moisture Measuring with I2C (ATtiny85)
Instructables tutorial by diy_bloke for building a DIY capacitive soil moisture sensor with I2C output using an ATtiny85. Inspired by the Chirp sensor, it covers PCB construction, firmware, and Arduino master code.
Firmware:Arduino
Use Cases:Environmental MonitoringEducation
Overview
An 8-step Instructables tutorial by diy_bloke that walks through building a capacitive soil moisture sensor with I2C communication from scratch. Inspired by the Chirp / Catnip Electronics sensor, the project uses an ATtiny85 as an I2C slave device and custom PCB plates as capacitive electrodes.
Components
- ATtiny85 microcontroller (I2C slave)
- PCB plates (~12x7 cm) as capacitive sensor electrodes
- HCT14 chip
- 2.2M resistor
- TinyWireS library for I2C slave implementation
What You Learn
- How capacitive soil moisture sensing works (avoiding electrode corrosion)
- Building an I2C slave device with ATtiny85
- Designing capacitive sensor electrodes from PCB material
- Reading the sensor from an Arduino master device