We’ve been covering and reviewing ANAVI open-source hardware boards for several years now, either standalone boards based on ESP8266, or add-on boards for Raspberry Pi.
The ANAVI Gardening uHAT is the latest board from Leon Anavi. It is a micro HAT designed for Raspberry Pi Zero to Raspberry Pi 4 SBCs that offers interfaces for soil sensors and other environmental sensors allowing measurements of soil moisture, atmospheric pressure and humidity, temperature with a waterproof sensor, and light intensity for gardening applications.
- Compatibility – Any Raspberry Pi board with a 40-pin GPIO header
- Storage – EEPROM for uHAT compliance
- 2x 3-pin headers for capacitive soil moisture sensors connected to Microchip MCP3002 ADC chip
- 3-pin One-wire terminal block for a waterproof temperature sensor
- 2x 4-pin I²C headers for additional sensors
- 10-header with GPIO pins for controlling irrigation systems and peripherals
- Misc – 2x user LEDs, UART pins for serial communication
- Dimensions – uHAT mechanical specifications with a valid ID EEPROM
- OSHWA certification – BG000079
As a side note, uHAT (Micro HAT) used to be called pHAT (partial HAT), but the Raspberry Pi Foundation changed that in 2018.
As with other ANAVI designs, the Gardening uHAT is fully open-source hardware with KiCAD schematics, PCB layout, BoM, and Gerber files, as well as software and documentation all available on Github. The project also just received certification from the Open Source Hardware Association with UID BG000079.
Code samples are available in C and Python and include support for the DS18B20 waterproof temperature sensor, the HTU21D sensor for temperature and humidity, the BH1750 sensor for light, the BMP180 sensor for barometric pressure, and capacitive soil-moisture sensors.
Other analog, I2C, and one-wire sensors can be supported too, but you’d have to handle programming on your own. That’s the same if you’d like to automate gardening, e.g. watering plants, with your Raspberry Pi.
The board is only offered as part as kits with the Starter Kit including the uHAT and two capacitive soil-moisture sensors, the Advanced Kit adding light, temperature, and humidity sensors, and the Developer Kit providing further functionality with a waterproof temperature sensor and a USB to serial debug cable.
You’ll find the kits for $28 to $48 on Crowd Supply with free shipping to the US and $12 to the rest of the world. Deliveries are expected to start around mid-February 2022.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.