This small device is suitable for many people with a small to medium-sized garden whom only require control over a few solenoids. It uses an MCP16331 DCDC converter to operate an ESP8285 or ESP32-C3 module on the same power supply as the reticulation valves, which typically operate on 24vac, 24vac rectified can reach voltages of up to 40v DC when the AC transformer is lightly loaded, this means that the converter must be able to withstand up to 45V which includes a safety margin of 5vdc.

The ESP-01M module from AI Thinker is available in ESP8285 and ESP32-C3 these are both pin compatible with this board. The module controls the solenoids via 4 Quadrant, 600v, 4a Triac, and while the board is fitted with TVS diodes currently, in testing I have found you could simply leave these off as they are not necessary for safe operation, and future design will see them removed.

The design also features 3 additional inputs for push buttons or LED these have a 1k resistor inline to the GPIO for safety and also to easily install LED indication lights if required. There is a 2.54mm 6 pin header that breaks out the pins required to flash the device with new firmware. There is a JST SH 1.0mm port with 4 pins that are connected to the hardware UART but can be used as SDA and SCL for I2C as well as 3.3v and GND this port allows for connection of expansion board in particular a real-time clock such as the MAX31328 or the older DS3231 and DS1307.

The mounting holes will suit a weatherproof enclosure if it is not used within an existing system as an upgrade, but as a new system, the case is from Allbro the part number is ENL160806P. It was made with Home Assistant in mind and works using ESPhome, making customization simple using YAML in ESPhome to create custom firmware for this device.