let us know your progress…Tks
Hi … i got two of them for my motorhome, looking to add them in HomeAssistant
Could this be a good starting point?
It has been integrated into Theengs Decoder, do you want to use with an ESP32 or a computer/raspberry?
Any one could connect to a BM2 with this?
Yes.
Esphome:
esphome:
name: bluetooth_gateway
platform: ESP32
board: esp-wrover-kit
includes:
- include.h
wifi:
ssid: ""
password: ""
# Enable logging
logger:
level: INFO
# Enable Home Assistant API
api:
ota:
# Enable Bluetooth scanning for this ESP32
esp32_ble_tracker:
sensor:
- platform: ble_client
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: XX:XX:XX:XX:XX:XX
id: bm2_battery_meter
One more thing, I am not 100% sure, but I think I copied include.h into /config/esphome/
That’s all, you will then have a sensor.voltage component in HA.
Great!
5 Likes
Hello
i got this error…any help would be apreciated
INFO Reading configuration /config/esphome/esphome-web-e044b0.yaml…
Failed config
INFO Reading configuration /config/esphome/esphome-web-e044b0.yaml…
INFO Generating C++ source…
INFO Compiling app…
Processing bluetoothgateway (board: esp-wrover-kit; framework: arduino; platform: platformio/espressif32 @ 3.5.0)
HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash
LDF: Library Dependency Finder → Library Dependency Finder (LDF) — PlatformIO latest documentation
Dependency Graph
|-- WiFi @ 1.0
|-- ESPmDNS @ 1.0
|-- Update @ 1.0
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/src/main.cpp.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/esp32-hal-touch.c.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/esp32-hal-uart.c.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/libb64/cdecode.c.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/libb64/cencode.c.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/main.cpp.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/stdlib_noniso.c.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/wiring_pulse.c.o
Compiling /data/bluetoothgateway/.pioenvs/bluetoothgateway/FrameworkArduino/wiring_shift.c.o
In file included from src/main.cpp:24:0:
src/include.h:1:1: error: ‘mbedtls’ does not name a type
mbedtls/aes.h
^
*** [/data/bluetoothgateway/.pioenvs/bluetoothgateway/src/main.cpp.o] Error 1
========================= [FAILED] Took 31.43 seconds =========================
You could change firmware of BM2 to include all data (voltage / Temp / Accelerometer) on the BLE broadcast advertisement. BM2 uses CC2541 BLE Module from texas instrument and most CC2541 Sample codes are opensource such as reading voltage data from ADC , or reading accelerometer data from I2C. BM2 has both ADC and Accelerometer via I2c. Repository also include sample ESP32 arduino code to read voltage and accelerometer data from CC2541 BLE Broadcasts
1 Like
It would be great if someone would be able to port the sample ESP32 Arduino code into ESPHOME compatible code.
1 Like
Did you have any luck with this?
Just had my battery go flat twice in the last week. Would love to be able to b track the voltage without needing to be stood next to the car.
Working here with OMG:
This worked well! Was able to integrate into my existing ESPHome BLE Bridge!
Just a friendly reminder that original app of BM2 is calling home, more on this:
2 Likes
Ya… a voltage divider. Esp boards have an ADC that does exactly this. No integration or hardly anything extra required.
Hi 1technophile
Just switched to omg from the esp home code.
Like the idea of being able to vary the scan interval etc.
I can see from the console that omg is connecting to the device & the bm2 shows under mqtt in home assistant but batt and voltage are just showing unknown.
Have I done something wrong or missed something in the setup?
Hello,
You could try to set the connection interval To every 10 minutes and wait a couple of hours with the BM2 close to the ESP32.
Sorted,
Found another forum post that was talking about the base topic, had to add home/back to the start of it, as soon as I put that back in front of BLE-BM2 it came up straight away.
Final dumb newbie question. If i want to have the BM2 update in real time i set the interval between scans/active scans slider to 0? and if I’m understanding the documentation correctly I whitelist the BM"'s mac and then turn the connection time up so that the ESP32 isnt constantly trying to connect to everything?
End goal is to have the sensor data update in real time in the morning before i leave for work, less frequently over night or at weekends,
To increase the voltage frequency update you can decrease the Time between connection to 1 minute, you could go also to 10s by an mqtt command (10000s):
Reduce also the scan interval to 10s in this case:
Ahh
I had scan and connections backwards.
Makes sense now I think.
I’ll test it out when I get home.
Thanks again for the help.
1 Like
is this currently working with ESPHome? if so, what is the best code to use to do the job?
thanks