Integrate Bluetooth battery monitoring devices (cars, motorbikes etc.)

Third party integrations
34

I managed to build an ESP32 in ESPHome last night that worked with this code and returned the voltage reading in mqqt. I put the include.h and secrets.yaml file in the config/esphome directory.
I’m guessing from the lambda part of the sensor code that the voltage source is encrypted, so does that help with making an update of OpenMQTTGateway, possibly?

esphome:
  name: esp32s3
  friendly_name: ESP32S3

  includes:
  - include.h

esp32:
  board: esp32-s3-devkitc-1
  framework:
    type: arduino

logger:

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

time:
  - platform: sntp
    id: sntp_time
    
web_server:
  port: 80

mqtt:
  broker: 192.168.0.XXX
  discovery: false
  topic_prefix: esphome/BM2
  username: mqtt-user
  password: XXXXXXXXX

esp32_ble_tracker:

sensor:
  - platform: ble_client
    type: characteristic
    ble_client_id: bm2_battery_meter
    name: Voltage
    service_uuid: 'fff0'
    characteristic_uuid: 'fff4'
    unit_of_measurement: 'V'
    accuracy_decimals: 2
    state_class: measurement
    device_class: voltage
    force_update: true
    notify: true
    lambda: |-
      mbedtls_aes_context aes;
      mbedtls_aes_init(&aes);
      unsigned char output[16];
      unsigned char key[16] = { 108, 101, 97, 103, 101, 110, 100, 255, 254, 49, 56, 56, 50, 52, 54, 54, };
      unsigned char iv[16] = {};
      mbedtls_aes_setkey_dec(&aes, key, 128);
      mbedtls_aes_crypt_cbc(&aes, MBEDTLS_AES_DECRYPT, 16, iv, (uint8_t*)&x[0], output);
      mbedtls_aes_free(&aes);
      return ((output[2] | (output[1] << 8)) >> 4) / 100.0f;  
 
ble_client:
  - mac_address: 94:A9:A8:42:72:43
    id: bm2_battery_meter
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