This project revolves around the topic of smart irrigation in smart homes. First release is a power supplied soil moisture sensor (Sense PS). It connects via MQTT to an IoT software such as Home Assistant, ioBroker, Node-RED or similar. Later, there will likely be a variant that is powered by a battery and a valve controller with flow meters to complete the irrigation system.
- Measurement of soil moisture and device temperature
- WiFi connection to an MQTT broker
- ESP32-C3 Super Mini DevBoard
- wide range power supply input 5...40V DC
- 3D printed housing
- strain relief
- epoxy resin encapsulated electronics to meet outdoor requirements
- usage of standard components
The schematic is quiet simple, only a few devices are put together.
You can buy the components at the following sources:
| Component | Name | Source |
|---|---|---|
| ESP32 Development Board | ESP32 C3 Super Mini | Ali Express |
| Soil Moisture Sensor | SoMoSe | Amazon Germany |
| Buck converter | DD4012SA (3.3V Version) | Ali Express |
| Soil Moisture Sensor | SoMoSe | Amazon Germany |
| Electrolytic Capacitor | 220uF /10V radial | Reichelt, Amazon, etc. |
| Power cable | H05RN-F 2x1 | Amazon, some hardware stores |
| Screws | M3 x 6mm | hardware store |
| Housing components | see housing 3D models folder | self printed |
The PCB has two layers with planes for 3.3V on top and GND on the bottom side. It is populated from both sides to achieve a compact form factor. The power cord leads are directly soldered to SMD pads on the PCB.
The ESP32 of the Sense PS can be programmed with the firmware of the manufacturer of the sensor available here. The firmware facilitates the following MQTT topics:
Published topics
| Topic | Values | Notes |
|---|---|---|
| somose_name/1/Humidity | number (0...255) | raw value of the sensor |
| somose_name/1/Humidity-Average | number (0...255) | smoothed, average value of the sensor |
| somose_name/1/Name | string | name of the sensor |
| somose_name/1/Temperature | number | temperature of the sensor in degree celsius |
For details on the MQTT topics see website of the sensor manufacturer. Be sure to have the ESP32 programmed before potting ;) After programming, the device is capable for OTA updates via its web interface.
For direct integration into Home Assistant, ESPhome configuration files also can be downloaded from the sensor manufacturer site.
All components are soldered to the PCB and mounted into the housing. The whole circuit is potted with 2 components resin to ensure outdoor capability. If someone is interested in a complete device including all parts (PCBA, ESP32, housing, etc.) you can contact me under elektroarzt@digital-filestore.de.
FloraGrow.Sense.PS.mounting.mp4
The Sense Board utilizes the excellent SoMoSe (Soil Moisture Sensor) developed by BeFIE you can find under https://github.com/BeFlE/SoMoSe and is sold on Amazon Germany