sbm2mqtt

Grab SwitchBot Meter data from Bluetooth Low Energy advertisements and publish them to an MQTT topic for use with Home Assistant, etc.

• Based in part on OpenWonderLabs/python-host, Switchbot_Py_Meter and switchbot-meter.py.
• Intended for use with Home Assistant but applicable to any system which can use MQTT.
• Applies to SwitchBot Meter devices with the BLE UUID cba20d00-224d-11e6-9fb8-0002a5d5c51b. I don't know if all SwitchBot Meter hardware and firmware versions share the same UUID.

Tested with:

• Pi Zero W & Pi 3B+ running Raspbian Buster Lite 2020-02-13
• SwitchBot Meters with firmware 2.5
• Python 3.7.3
• Local MQTT broker
• Home Assistant 0.106 configured to connect to the local MQTT broker (optional)

Background

TL;DR Start with a fresh install of Raspbian Buster Lite. Don't install the dependencies recommended by OpenWonderLabs for python-host.

OpenWonderLabs published the open API for SwitchBot Meters in late 2019. bbostock here and warpzone on Qiita posted the first Python scripts I saw to taking advantage of it. bbostock's script also featured MQTT publishing for integration with Home Assistant.

For reasons that I still can't figure out, neither script worked for me on a Pi 4 or Pi Zero W. The firmware on my Meters was updated from 2.4 to 2.5 as I was starting to work with them. That caused the device model names (WOSensorTH) to not be visible when doing a BLE scan, although the MACs still were. It initially appeared that the firmware upgrade may have been the cause for my Meters failing to work with the scripts.

When OpenWonderLabs posted a new script that worked with my Meters, I used it as a starting point to create my own, resulting in sbm2mqtty. I tested that with my original Pi Zero W set up as well as on a Pi 3B+ with fresh Raspbian Buster Lite. bbostock's and warpzone's scripts run successfully on the 3B+, as well.

So, my best guess is that the original failure with bbostock's and warpzone's scripts was something to due with the environments on the Pi4 and Pi Zero W caused by OpenWonderLabs' somewhat complicated dependency installation recommendations for python-host.

I suggest that you don't first follow OpenWonderLabs' dependency installation recommendations for python-host. They are not necessary for sbm2mqtt and may have been the cause of my earlier failures.

Operation

sbm2mqtt works like this:

• Scan for Bluetooth Low Energy devices, looking for SwitchBot Meters.
• For each SwitchBot Meter, grab the MAC address, temperature, humidity and battery level from the BLE advertisement.
• Publish the temperature, humidity and battery level for each SwitchBot Meter separately to an MQTT topic that includes the MAC address.
• Print the values to the terminal (if not running in the background) and save them to a log.
• If you also configure Home Assistant with MQTT sensors for the sbm2mqtt MQTT topics, HA updates the states of those sensors with every new MQTT message.

Installation

sbm2mqtt needs the BluePy and Paho MQTT libraries. Run the following commands on a fresh installation of Raspbian Buster Lite:

$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install python3-pip libglib2.0-dev
$ sudo pip3 install bluepy
$ sudo pip3 install paho-mqtt

Create a directory called switchbot containing the files:

sbm2mqtt.py
sbm2mqtt_config.py

You don't need to edit sbm2mqtt.py . Edit sbm2mqtt_config.py with your settings for:

# MQTT Settings
mqtt_host = 'xxx.xxx.xxx.xxx'
mqtt_port = xxxx
mqtt_timeout = 30
mqtt_client = 'switchbot_meter_checker'
mqtt_user = 'xxxxxx'
mqtt_pass = 'xxxxxx'
mqtt_topic = 'switchbot_meter/'

Execute sqm2mqtt in the terminal, and note the MAC addresses of any SwitchBot meters it finds.

If you want to integrate with Home Assistant, add three sensor: entries to configuration.yaml for each Meter, as follows:

sensor:
- platform: mqtt
  name: 'name_of_this_meter_temperature'
  state_topic: 'switchbot_meter/xx:xx:xx:xx:xx:xx' # MAC address of this meter
  value_template: '{{ value_json.temperature }}'
  unit_of_measurement: '°C' # Change to '°F' as appropriate
- platform: mqtt
  name: 'name_of_this_meter_humidity'
  state_topic: 'switchbot_meter/xx:xx:xx:xx:xx:xx' # MAC address of this meter
  value_template: '{{ value_json.humidity }}'
  unit_of_measurement: '%'
  icon: mdi:water-percent
- platform: mqtt
  name: 'name_of_this_meter_battery'
  state_topic: 'switchbot_meter/xx:xx:xx:xx:xx:xx' # MAC address of this meter
  value_template: '{{ value_json.battery }}'
  unit_of_measurement: '%'
  icon: mdi:battery

If you have a split configuration, paste in the contents of the sensors.yaml file to your sensor configuration file and edit appropriately.

Use

To execute sbm2mqtt in the switchbot directory:

$ sudo python3 sbm2mqtt.py

To run sbm2mqtt in the background automatically every five minutes and also log what it's doing (Thanks, bbostock.):

$ sudo nano /etc/crontab

and add:

*/5 *   * * *   pi      sudo python3 /home/pi/switchbot/sbm2mqtt.py >> /home/pi/switchbot/sbm2mqtt.log 2>&1

If you have a different user name or used a different directory structure, edit accordingly.

Your output should look something like this:

Scanning for SwitchBot Meters...

f5:49:7c:bb:xx:46 @ 2020-03-30 14:26:02
  Temp: 21.0° C
  Humidity: 29%
  Battery: 100%

  Publishing MQTT payload to switchbot_meter/f5:49:7c:bb:xx:46 ...

    {"time":"2020-03-30 14:26:02","temperature":21.0,"humidity":29,"battery":100,"temperature_scale":"C"}

c9:c7:8d:fb:xx:65 @ 2020-03-30 14:26:05
  Temp: 69.8° F
  Humidity: 30%
  Battery: 100%

  Publishing MQTT payload to switchbot_meter/c9:c7:8d:fb:xx:65 ...

    {"time":"2020-03-30 14:26:05","temperature":69.8,"humidity":30,"battery":100,"temperature_scale":"F"}

Finished.

That's it. You should be good to go.