flora

This arduino sketch implements an ESP32 BLE client for XIaomi Mi Flora Plant sensors, pushing the meaasurements to an MQTT server.

Technical requirements

Hardware:

• ESP32
• Xiaomi Mi Plant Sensor (firmware revision >= 2.6.6)

Software:

• MQTT server

Setup instructions

1. Copy config.h.example into config.h and update seetings according to your environment:

• WLAN SSID and password
• MQTT Server address
• MAC address(es) of your Xiaomi Mi Plant sensor(s)

2. Open ino sketch in Arduino, compile & upload.

Measuring interval

The ESP32 will perform a single connection attempt to the Xiaomi Mi Plant sensor, read the sensor data & push it to the MQTT server. The ESP32 will enter deep sleep mode after all sensors have been read and sleep for X minutes before repeating the exercise... Battery level is read every Xth wakeup. Up to X attempst per sensor are performed when reading the data fails.

Configuration

• SLEEP_DURATION - how long should the device sleep between sensor reads?
• EMERGENCY_HIBERNATE - how long after wakeup should the device forcefully go to sleep (e.g. when something gets stuck)?
• BATTERY_INTERVAL - how ofter should the battery status be read?
• RETRY - how ofter should a single device be tried on each run?

Constraints

Some "nice to have" features are not yet implemented or cannot be implemented:

• OTA updates: I didn't manage to implement OTA update capabilities due to program size constraints: BLE and WLAN brings the sketch up to 90% of the size limit, so I decided to use the remaining 10% for something more useful than OTA...

Sketch size issues

The sketch does not fit into the default arduino parition size of around 1.3MB. You'll need to change your default parition table and increase maximum build size to at least 1.6MB. On Arduino IDE this can be achieved using "Tools -> Partition Scheme -> No OTA"

Credits

Many thanks go to the guys at https://github.com/open-homeautomation/miflora for figuring out the sensor protocol.