[BT] Add BM2 voltage (#1495)

* [BT] Add BM2 voltage

Voltage retrieval through a BLE connection, frequency of the BLE connection is defined by `intervalcnct`

* Add doc

Credits to https://github.com/KrystianD/bm2-battery-monitor

docs/prerequisites/devices.md

@@ -28,7 +28,7 @@ Added to that it retrieves the measures from the devices below. By default the d
 | BlueMaestro|TempoDisc 1 in 1|temperature/battery|
 | BlueMaestro|TempoDisc 3 in 1|temperature/humidity/dew point/battery|
 | BlueMaestro|TempoDisc 4 in 1|temperature/humidity/pressure/battery|
-| BM2 Battery Monitor|BM2|battery|
+| BM2 Battery Monitor|BM2|battery/volt(c)|
 | ClearGrass|CGG1|temperature/humidity/battery/voltage (depending on which CGG1 firmware is installed)|
 | ClearGrass alarm clock|CGD1|temperature/humidity/battery|
 | ClearGrass alarm clock|CGC1|temperature/humidity/battery|
@@ -84,7 +84,7 @@ Added to that it retrieves the measures from the devices below. By default the d
 | ThermoPro|TP393|temperature/humidity|
 | TPMS|TPMS|temperature/pressure/battery/alarm/count|
 | Vegtrug||temperature/moisture/luminance/fertility|
-| XIAOMI Mi Flora|HHCCJCY01HHCC|temperature/moisture/luminance/fertility/battery(1)(c)|
+| XIAOMI Mi Flora|HHCCJCY01HHCC|temperature/moisture/luminance/fertility/battery(c)|
 | XIAOMI Ropot|HHCCPOT002|temperature/moisture/fertility|
 | XIAOMI Mi Jia|LYWSDCGO|temperature/humidity/battery|
 | XIAOMI Mi Jia|LYWSD02|temperature/humidity/battery|

main/ZgatewayBLEConnect.h

@@ -41,6 +41,15 @@ public:
   void publishData() override;
 };
 
+class BM2_connect : public zBLEConnect {
+  //std::vector<uint8_t> m_data;
+  void notifyCB(NimBLERemoteCharacteristic* pChar, uint8_t* pData, size_t length, bool isNotify);
+
+public:
+  BM2_connect(NimBLEAddress& addr) : zBLEConnect(addr) {}
+  void publishData() override;
+};
+
 class GENERIC_connect : public zBLEConnect {
   std::vector<uint8_t> m_data;
 

main/ZgatewayBLEConnect.ino

@@ -4,7 +4,6 @@
 #    include "ArduinoJson.h"
 #    include "ArduinoLog.h"
 #    include "ZgatewayBLEConnect.h"
-
 #    define convertTemp_CtoF(c) ((c * 1.8) + 32)
 
 extern bool ProcessLock;
@@ -255,6 +254,81 @@ void DT24_connect::publishData() {
   }
 }
 
+/*-----------------------BM2 HANDLING-----------------------*/
+void BM2_connect::notifyCB(NimBLERemoteCharacteristic* pChar, uint8_t* pData, size_t length, bool isNotify) {
+  if (m_taskHandle == nullptr) {
+    return; // unexpected notification
+  }
+
+  if (!ProcessLock) {
+    Log.trace(F("Callback from %s characteristic" CR), pChar->getUUID().toString().c_str());
+    if (length == 16) {
+      Log.trace(F("Device identified creating BLE buffer" CR));
+      JsonObject& BLEdata = getBTJsonObject();
+      String mac_address = m_pClient->getPeerAddress().toString().c_str();
+      mac_address.toUpperCase();
+      BLEdata["model"] = "BM2 Battery Monitor";
+      BLEdata["id"] = (char*)mac_address.c_str();
+      mbedtls_aes_context aes;
+      mbedtls_aes_init(&aes);
+      unsigned char output[16];
+      unsigned char iv[16] = {};
+      unsigned char key[16] = {
+          108,
+          101,
+          97,
+          103,
+          101,
+          110,
+          100,
+          255,
+          254,
+          49,
+          56,
+          56,
+          50,
+          52,
+          54,
+          54,
+      };
+      mbedtls_aes_setkey_dec(&aes, key, 128);
+      mbedtls_aes_crypt_cbc(&aes, MBEDTLS_AES_DECRYPT, 16, iv, (uint8_t*)&pData[0], output);
+      mbedtls_aes_free(&aes);
+      float volt = ((output[2] | (output[1] << 8)) >> 4) / 100.0f;
+      BLEdata["volt"] = volt;
+      Log.trace(F("volt: %F" CR), volt);
+      pubBT(BLEdata);
+    } else {
+      Log.notice(F("Invalid notification data" CR));
+      return;
+    }
+  } else {
+    Log.trace(F("Callback process canceled by processLock" CR));
+  }
+
+  xTaskNotifyGive(m_taskHandle);
+}
+
+void BM2_connect::publishData() {
+  NimBLEUUID serviceUUID("fff0");
+  NimBLEUUID charUUID("fff4");
+  NimBLERemoteCharacteristic* pChar = getCharacteristic(serviceUUID, charUUID);
+
+  if (pChar && pChar->canNotify()) {
+    Log.trace(F("Registering notification" CR));
+    if (pChar->subscribe(true, std::bind(&BM2_connect::notifyCB, this,
+                                         std::placeholders::_1, std::placeholders::_2,
+                                         std::placeholders::_3, std::placeholders::_4))) {
+      m_taskHandle = xTaskGetCurrentTaskHandle();
+      if (ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(BLE_CNCT_TIMEOUT)) == pdFALSE) {
+        m_taskHandle = nullptr;
+      }
+    } else {
+      Log.notice(F("Failed registering notification" CR));
+    }
+  }
+}
+
 /*-----------------------HHCCJCY01HHCC HANDLING-----------------------*/
 void HHCCJCY01HHCC_connect::publishData() {
   NimBLEUUID serviceUUID("00001204-0000-1000-8000-00805f9b34fb");

main/ZgatewayBT.ino

@@ -453,6 +453,18 @@ void DT24Discovery(const char* mac, const char* sensorModel_id) {
   createDiscoveryFromList(mac, DT24sensor, DT24parametersCount, "DT24", "ATorch", sensorModel_id);
 }
 
+void BM2Discovery(const char* mac, const char* sensorModel_id) {
+#    define BM2parametersCount 2
+  Log.trace(F("BM2Discovery" CR));
+  const char* BM2sensor[BM2parametersCount][9] = {
+      {"sensor", "volt", mac, "voltage", jsonVolt, "", "", "V", stateClassMeasurement},
+      {"sensor", "batt", mac, "battery", jsonBatt, "", "", "%", stateClassMeasurement}
+      //component type,name,availability topic,device class,value template,payload on, payload off, unit of measurement
+  };
+
+  createDiscoveryFromList(mac, BM2sensor, BM2parametersCount, "BM2", "Generic", sensorModel_id);
+}
+
 void LYWSD03MMCDiscovery(const char* mac, const char* sensorModel) {
 #    define LYWSD03MMCparametersCount 4
   Log.trace(F("LYWSD03MMCDiscovery" CR));
@@ -515,6 +527,7 @@ void LYWSD03MMCDiscovery(const char* mac, const char* sensorModel) {}
 void MHO_C401Discovery(const char* mac, const char* sensorModel) {}
 void HHCCJCY01HHCCDiscovery(const char* mac, const char* sensorModel) {}
 void DT24Discovery(const char* mac, const char* sensorModel_id) {}
+void BM2Discovery(const char* mac, const char* sensorModel_id) {}
 void XMWSDJ04MMCDiscovery(const char* mac, const char* sensorModel_id) {}
 #  endif
 
@@ -654,6 +667,10 @@ void BLEconnect() {
             DT24_connect BLEclient(addr);
             BLEclient.processActions(BLEactions);
             BLEclient.publishData();
+          } else if (p->sensorModel_id == BLEconectable::id::BM2) {
+            BM2_connect BLEclient(addr);
+            BLEclient.processActions(BLEactions);
+            BLEclient.publishData();
           } else if (p->sensorModel_id == TheengsDecoder::BLE_ID_NUM::HHCCJCY01HHCC) {
             HHCCJCY01HHCC_connect BLEclient(addr);
             BLEclient.processActions(BLEactions);
@@ -682,6 +699,7 @@ void BLEconnect() {
                 if (p->sensorModel_id != BLEconectable::id::DT24_BLE &&
                     p->sensorModel_id != TheengsDecoder::BLE_ID_NUM::HHCCJCY01HHCC &&
                     p->sensorModel_id != BLEconectable::id::LYWSD03MMC &&
+                    p->sensorModel_id != BLEconectable::id::BM2 &&
                     p->sensorModel_id != BLEconectable::id::MHO_C401 &&
                     p->sensorModel_id != BLEconectable::id::XMWSDJ04MMC) {
                   // if irregulary connected to and connection failed clear the connect flag.
@@ -892,7 +910,7 @@ void launchBTDiscovery(bool overrideDiscovery) {
       if (!BTConfig.extDecoderEnable && // Do not decode if an external decoder is configured
           p->sensorModel_id > TheengsDecoder::BLE_ID_NUM::UNKNOWN_MODEL &&
           p->sensorModel_id < TheengsDecoder::BLE_ID_NUM::BLE_ID_MAX &&
-          p->sensorModel_id != TheengsDecoder::BLE_ID_NUM::HHCCJCY01HHCC) { // Exception on HHCCJCY01HHCC as this one is discoverable and connectable for battery retrieving
+          p->sensorModel_id != TheengsDecoder::BLE_ID_NUM::HHCCJCY01HHCC && p->sensorModel_id != TheengsDecoder::BLE_ID_NUM::BM2) { // Exception on HHCCJCY01HHCC and BM2 as these ones are discoverable and connectable
         Log.trace(F("Looking for Model_id: %d" CR), p->sensorModel_id);
         std::string properties = decoder.getTheengProperties(p->sensorModel_id);
         Log.trace(F("properties: %s" CR), properties.c_str());
@@ -938,11 +956,14 @@ void launchBTDiscovery(bool overrideDiscovery) {
       } else {
         if (p->sensorModel_id > BLEconectable::id::MIN &&
                 p->sensorModel_id < BLEconectable::id::MAX ||
-            p->sensorModel_id == TheengsDecoder::BLE_ID_NUM::HHCCJCY01HHCC) {
+            p->sensorModel_id == TheengsDecoder::BLE_ID_NUM::HHCCJCY01HHCC || p->sensorModel_id == TheengsDecoder::BLE_ID_NUM::BM2) {
           // Discovery of sensors from which we retrieve data only by connect
           if (p->sensorModel_id == BLEconectable::id::DT24_BLE) {
             DT24Discovery(macWOdots.c_str(), "DT24-BLE");
           }
+          if (p->sensorModel_id == BLEconectable::id::BM2) {
+            BM2Discovery(macWOdots.c_str(), "BM2");
+          }
           if (p->sensorModel_id == BLEconectable::id::LYWSD03MMC) {
             LYWSD03MMCDiscovery(macWOdots.c_str(), "LYWSD03MMC");
           }
@@ -1032,6 +1053,8 @@ void process_bledata(JsonObject& BLEdata) {
         model_id = BLEconectable::id::LYWSD03MMC;
       else if (name.compare("DT24-BLE") == 0)
         model_id = BLEconectable::id::DT24_BLE;
+      else if (name.compare("Battery Monitor") == 0)
+        model_id = BLEconectable::id::BM2;
       else if (name.compare("MHO-C401") == 0)
         model_id = BLEconectable::id::MHO_C401;
       else if (name.compare("XMWSDJ04MMC") == 0)

main/config_BT.h

@@ -209,6 +209,7 @@ public:
     LYWSD03MMC,
     MHO_C401,
     DT24_BLE,
+    BM2,
     XMWSDJ04MMC,
     MAX,
   };