Support for the device BTH01

[duelago]

Hello!

I successfully flashed pvvx firmware on my bluetooth device.
Model: BTH01
Firmware: github.com /pvvx
Hardware: 0014
Software: V1.9

My goal is to use your software on an esp32 to change color on an LED depending on the temperature. Your code is picking up my device but it returns 0 degrees. I'm using your basic example code (The non blocking version is crashing my device)

17:16:48.005 -> Sensor 0: 34:EC:B6:65:18:3E
17:16:48.005 -> Name: BTH01-David
17:16:48.005 -> 0.00°C
17:16:48.005 -> 0.00%
17:16:48.005 -> 0.000V
17:16:48.005 -> 0%
17:16:48.005 -> -75dBm
17:16:48.005 -> Measurement Count: 0
17:16:48.062 -> Reed Switch State: Closed
17:16:48.062 -> GPIO TRG Output: Low
17:16:48.062 -> Control Parameters: Not Set
17:16:48.062 -> Temperature Trigger Event: Not Triggered
17:16:48.062 -> Humidity Trigger Event: Not Triggered
17:16:48.062 ->
17:16:48.062 -> BLE Devices found (total): 5
17:16:48.062 -> Iteration 2 - Free heap is 228720
17:16:48.062 -> ---

I get my temperature when using the web site on my computer:
https://pvvx.github.io/THB2/web/PHY62x2BTHome.html

Any ideas how I can solve this?

/David

[matthias-bs]

Hello David,

I suppose the data for this sensor is placed and/or encoded differently in the BLE advertising message as compared to the Xiaomi Mijia (LYWSD03MMC).
Have you checked https://github.com/pvvx/THB2/blob/ba0601e1db3e640ad0377c9b7d1f5f6aff52bb95/bthome_phy6222/source/thservice.c#L31?

Cheers,
Matthias

[matthias-bs]

Ah, it seems you don't have check the source code!

• https://github.com/pvvx/THB2/tree/master?tab=readme-ov-file#main-features says:

  BLE advertisement interval in BTHome v2 format is 5 seconds.

• At the top of https://bthome.io/, you find a link to data format

[matthias-bs]

Maybe this could be helpful, too: https://github.com/Bluetooth-Devices/bthome-ble/blob/main/src/bthome_ble/parser.py

[duelago]

Ah, it seems you don't have check the source code!

• https://github.com/pvvx/THB2/tree/master?tab=readme-ov-file#main-features says:
  BLE advertisement interval in BTHome v2 format is 5 seconds.
• At the top of https://bthome.io/, you find a link to data format

Thank you! I am not much of a programmer but my friend ChatGPT and the documentation helped me. This code works for me now :)

#include <NimBLEDevice.h>

// BLE Scan settings
NimBLEScan* pBLEScan;
const int scanTime = 5;  // Scan duration in seconds

// Target MAC address of the specific device
const std::string targetMacAddress = "34:ec:b6:65:18:3e";

// Helper function to decode a little-endian 16-bit unsigned integer
uint16_t decodeLittleEndianU16(uint8_t lowByte, uint8_t highByte) {
  return (uint16_t)((highByte << 8) | lowByte);
}

// Helper function to print the raw service data
void printRawServiceData(const std::string& payload) {
  Serial.print("Raw Service Data: ");
  for (size_t i = 0; i < payload.length(); ++i) {
    Serial.printf("%02X ", static_cast<uint8_t>(payload[i]));
  }
  Serial.println();
}

// Function to parse and decode the raw service data
void decodeServiceData(const std::string& payload) {
  // Print the raw service data for debugging
  printRawServiceData(payload);

  // Ensure we have at least 14 bytes for the expected data
  if (payload.length() >= 14) {
    // Check if the first byte indicates a valid service data format
    if (payload[0] == 0x40) {
      // Parse BTHome device info (flags and version)
      uint8_t flags = payload[0];  // First byte (flag byte)
      uint8_t bthomeVersion = (flags >> 5) & 0x07;  // BTHome Version is in bits 5-7
      Serial.print("BTHome Version: ");
      Serial.println(bthomeVersion);

      // Decode temperature (bytes 6 and 7) in little-endian format
      int16_t temp_int = (payload[6] & 0xff) | ((payload[7] & 0xff) << 8);
      float temperature = temp_int / 100.0;
      Serial.print("Temperature: ");
      Serial.print(temperature);
      Serial.println(" °C");

      // Decode humidity (bytes 9 and 10) in little-endian format
      float humidity = ((payload[9] & 0xff) | ((payload[10] & 0xff) << 8)) / 100.0;
      Serial.print("Humidity: ");
      Serial.print(humidity);
      Serial.println(" %");

      // Decode voltage (bytes 12 and 13) in little-endian format
      float voltage = ((payload[12] & 0xff) | ((payload[13] & 0xff) << 8)) / 1000.0;
      Serial.print("Voltage: ");
      Serial.print(voltage);
      Serial.println(" V");

      // Check validity of decoded values based on ESPHome's conditions
      if (payload[5] == 0x02 && payload[8] == 0x03 && payload[11] == 0x0C &&
          temperature > -40 && temperature < 100 && humidity > 0 && humidity < 101 && voltage > 0 && voltage < 4) {
        
        // Publish the values (you can replace these with your actual publish method)
        Serial.print("Publishing Data: ");
        Serial.print("Temperature: ");
        Serial.print(temperature);
        Serial.print(" Humidity: ");
        Serial.print(humidity);
        Serial.print(" Voltage: ");
        Serial.println(voltage);
        
        // Here, replace with your own logic to publish the data
        // id(BTH01_temperature_).publish_state(temperature);
        // id(BTH01_humidity_).publish_state(humidity);
        // id(BTH01_volt_).publish_state(voltage);
      }
    } else {
      Serial.println("Invalid Service Data format.");
    }
  } else {
    Serial.println("Unexpected payload length or structure.");
  }
}

// Callback to handle BLE Advertisements
class MyAdvertisedDeviceCallbacks : public NimBLEAdvertisedDeviceCallbacks {
  void onResult(NimBLEAdvertisedDevice* advertisedDevice) {
    // Check if the device's MAC address matches the target address
    if (advertisedDevice->getAddress().toString() == targetMacAddress) {
      Serial.print("Found target device: ");
      Serial.println(advertisedDevice->getAddress().toString().c_str());

      // Check if the device has service data
      if (advertisedDevice->haveServiceData()) {
        std::string serviceData = advertisedDevice->getServiceData();
        Serial.print("Service Data Length: ");
        Serial.println(serviceData.length());
        decodeServiceData(serviceData);
      } else {
        Serial.println("No service data available.");
      }
    }
  }
};

void setup() {
  Serial.begin(115200);
  Serial.println("Starting BLE Scanner...");

  // Initialize BLE
  NimBLEDevice::init("");
  pBLEScan = NimBLEDevice::getScan();
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks(), true);
  pBLEScan->setInterval(100);
  pBLEScan->setWindow(99);
  pBLEScan->setActiveScan(true);
}

void loop() {
  Serial.println("Scanning for BLE devices...");
  pBLEScan->start(scanTime, false);  // Scan for `scanTime` seconds
  delay(2000);  // Wait before the next scan
}

[matthias-bs]

Nice!

[olivluca]

I seriously doubt that your code works (it doesn't here 😉) , it's just another chatgpt hallucination: according to the specification, the payload isn't necessarily 14 bytes and the values aren't in a fixed location, but each byte, after the initial 0x40, specifies what comes after it, e.g. I'm getting

Raw Service Data: 40 00 60 01 5F 02 EC 07 03 C3 1B (11 bytes)

and it means:

00 -> packet id (60)
01 -> battery (5F, 95%)
02 -> temperature (07EC, 20.28)
03 -> humidity (1BC3, 71.07%)

Then for the same thermometer I get

Raw Service Data: 40 00 61 0C 2A 0B 10 01 (8 bytes)

00 -> packet id (61)
0C -> voltage (0B2A, 2.858V)
10 -> power (01, true)