Compost sensor v3

Multiple, independent sensors broadcasting over LoRa to a base station. Sensors are automatically discovered and added with unqiue short IDs. Base station uploads data to Home Assistant with MQTT over WiFi. Soil temperature, air temperature, LoRa and WiFi RSSI, and battery levels. Appears in Home Assistant as a single device:

Hardware

• Sensor (TX)
  • Adafruit Feather M0 with RFM95 LoRa Radio - 900MHz - RadioFruit
  • Simple Spring Antenna - 915MHz
  • Platinum RTD Sensor - PT1000 - 3 Wire 1 meter long
  • Adafruit PT1000 RTD Temperature Sensor Amplifier - MAX31865
  • Adafruit STEMMA Soil Sensor - I2C Capacitive Moisture Sensor - JST PH 2mm
    • Note: These seem unreliable, and drain the battery. Testing Chirp! sensors next.
• Base Station (RX)
  • Adafruit Feather M0 WiFi - ATSAMD21 + ATWINC1500
  • Adafruit LoRa Radio FeatherWing - RFM95W 900 MHz - RadioFruit
• LiPo batteries
  • Lithium Ion Cylindrical Battery - 3.7v 2200mAh
  • Lithium Ion Polymer Battery - 3.7v 500mAh Lithium Ion Polymer Battery - 3.7v 500mAh
• Stainless steel tube for temperature probe
  • Aliexpress Seiko Metal Store
  • Length 500mm x 1Pcs, OD5mm X ID4.2mm, feels a little too easy to bend. Easy fit in tube, might allow more epoxy for a stronger bond.
  • Length 500mm x 1Pcs, OD5mm X ID4mm, feels stiffer. Need to trim blob of epoxy of on PT1000D for it to fit in.
  • Another 150-250mm in length would be nice.
  • Be careful buying elsewhere, tolerances on eBay stuff is junk.

Software

• Latest Ardunio IDE
• Legacy v1.8.X Arduino IDE (for WiFi firmware updates)

Libraries

All of these except RadioHead can be installed through the library manager in Arduino IDE.

• Arduino SAMD
• Adafruit SAMD Boards
• RTCZero
• RadioHead (get the latest version instead of Adafruit github copy)
• Wifi101
• home-assistant-integration
  • Note: My PR is required for dynamic sensor creation
• Adafruit Seesaw

Set up environment

• Add board to Arduino IDE
• Install libraries

Update Firmware

1. Open Arduino IDE (latest)
2. Open Wifi101 Firmware Updater sketch
3. Add this line to setup(): WiFi.setPins(8,7,4,2);
4. Upload Wifi101 firmware updater sketch example
5. Close Arduino IDE and open legacy Arduino IDE
6. Open Wifi101 Firmware updater from Tools menu
7. Select correct port
8. Test connection
9. Update firmware

Home Assistant

1. Set up an MQTT broker like Mosquito
2. Create a new HA user dedicated to the sensor

Configure

Both RX and TX sketches need a config.h

1. Copy config.h.example to config.h
2. Add your WiFi and MQTT details to the RX config.h
3. Add your soil moisture sensor calibration values to the TX config.h
4. Upload the RX sketch to the base station
5. Upload the TX sketch to the sensor

Testing

1. Monitor serial output on each sensor
2. Look for Wifi connected
3. Look for Sensor transmitting
4. Look for Base receiving sensor data
5. Check HA to confirm communication