I Connected My Withings Body+ to Home Assistant with an ESP32

Call it what you will, the point is I do not have the necessary skills to accomplish this task, but I was able to go from an APK to a working implementation that was controlling the lights in my RV in a couple of hours back in early April using whatever was the current version of Opus at the time. While I understand what it did to accomplish this, it might as well be magic for me, because it would take me months of free time to get to where it got.

It also wrote out documentation of the protocol so subsequent work would not require reading decompiled Java code.

I'm just using a cheap ESP-WROOM-32 but the recommended way to do it is with an wired ethernet-based ESP32 so you don't have interference with the wifi and btle. For a scale this works well enough. I haven't yet received the athom smart plug so I can't recommend it yet. Should be here in a week or so.

Once you've got the proxy you can just use the eufylife integration: https://www.home-assistant.io/integrations/eufylife_ble/

To setup the esphome bluetooth proxy you install esphome, and then create a yaml file that you'll use to configure the board, like this:

   esphome:
     name: bluetooth-proxy
   
   esp32:
     board: esp32dev
     framework:
       type: esp-idf
   
   # Enable logging
   logger:
   
   # Enable Home Assistant API
   api:
     encryption:
       key: "YOUR_KEY_HERE"
   
   # Enable OTA updates
   ota:
     - platform: esphome
   
   # WiFi configuration (matching the settings from your other devices)
   wifi:
     ssid: "YOUR_WIFI_SSID"
     password: "YOUR_WIFI_PASSWORD"
   
     # Enable fallback hotspot (captive portal) in case wifi connection fails
     ap:
       ssid: "Bluetooth Proxy Fallback"
       password: "proxyfallback"
   
   captive_portal:
   
   # Enable ESP32 BLE Tracker
   esp32_ble_tracker:
     scan_parameters:
       active: true
   
   # Enable Bluetooth Proxy
   bluetooth_proxy:
     active: true