BME680 support (experimental)

README.md

@@ -47,6 +47,7 @@ Depending on board hardware following features are supported:
 - Silicon unique ID
 - Battery voltage monitoring
 - GPS (Generic serial NMEA, or Quectel L76 I2C)
+- MEMS sensor (Bosch BME680)
 
 Target platform must be selected in [platformio.ini](https://github.com/cyberman54/ESP32-Paxcounter/blob/master/platformio.ini).<br>
 Hardware dependent settings (pinout etc.) are stored in board files in /hal directory. If you want to use a ESP32 board which is not yet supported, use hal file generic.h and tailor pin mappings to your needs. Pull requests for new boards welcome.<br>
@@ -198,6 +199,14 @@ Hereafter described is the default *plain* format, which uses MSB bit numbering.
 	byte 1:		Beacon RSSI reception level
 	byte 2:		Beacon identifier (0..255)
 
+**Port #7:** BME680 query result
+
+	bytes 1-2:	Temperature [°C]
+	bytes 3-4:	Pressure [hPa]
+	byte 5:		Humidity [%]
+	bytes 6-7:	Gas resistance [MOhm]
+	bytes 8-9:	Altitude [meter]
+
 # Remote control
 
 The device listenes for remote control commands on LoRaWAN Port 2. Multiple commands per downlink are possible by concatenating them.
@@ -310,6 +319,10 @@ Note: all settings are stored in NVRAM and will be reloaded when device starts.
 
 	Device answers with it's current status on Port 4. 
 
+0x85 get BME680 sensor data
+
+	Device answers with BME680 sensor data set on Port 7.
+
 	
 # License
 

include/bme680read.h

@@ -2,17 +2,15 @@
 #define _HAS_BME
 
 #include "globals.h"
-
 #include <Wire.h>
-#include <SPI.h>
 #include <Adafruit_Sensor.h>
 #include "Adafruit_BME680.h"
 
-extern Adafruit_BME680 bme; // Make TinyGPS++ instance globally availabe
+extern Adafruit_BME680 bme; // Make bme instance globally availabe
 extern bmeStatus_t
     bme_status; // Make struct for storing gps data globally available
-extern TaskHandle_t BmeTask;
 
-void bme_loop(void *pvParameters);
+void bme_init();
+bool bme_read();
 
 #endif

include/globals.h

@@ -47,11 +47,11 @@ typedef struct {
 } gpsStatus_t;
 
 typedef struct {
-  float_t temperature;
+  uint16_t temperature; // Temperature * 100 in degrees Centigrade
-  float_t pressure;
+  uint16_t pressure; // Barometic pressure in hecto pascals
-  float_t humidity;
+  uint8_t humidity; // Relative humidity in percent
-  float_t gas_resistance;
+  uint32_t gas_resistance; // Resistance in Ohms
-  float_t altitude;
+  uint16_t altitude; // Altitude in meters
 } bmeStatus_t;
 
 // global variables

src/bme680read.cpp

@@ -1,64 +1,46 @@
 #ifdef HAS_BME
 
-#include "globals.h"
+#include "bme680read.h"
 
 // Local logging tag
 static const char TAG[] = "main";
 
-#include <Wire.h>
-#include <SPI.h>
-#include <Adafruit_Sensor.h>
-#include "Adafruit_BME680.h"
-
 #define SEALEVELPRESSURE_HPA (1013.25)
 
 // I2C Bus interface
 Adafruit_BME680 bme;
 
 bmeStatus_t bme_status;
-TaskHandle_t BmeTask;
-
-// BME680 read loop Task
-void bme_loop(void *pvParameters) {
-
-  configASSERT(((uint32_t)pvParameters) == 1); // FreeRTOS check
-
-  // initialize BME680 sensor
-  if (!bme.begin()) {
-    ESP_LOGE(TAG, "BME680 chip not found on i2c bus, bus error %d. "
-                  "Stopping BME task.");
-    vTaskDelete(BmeTask);
-  } else {
-    ESP_LOGI(TAG, "BME680 chip found.");
-  }
 
+void bme_init(void) {
+  // initialize BME680 sensor using default i2c address 0x77
+  if (bme.begin()) {
     // Set up oversampling and filter initialization
     bme.setTemperatureOversampling(BME680_OS_8X);
     bme.setHumidityOversampling(BME680_OS_2X);
     bme.setPressureOversampling(BME680_OS_4X);
     bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
     bme.setGasHeater(320, 150); // 320*C for 150 ms
+    ESP_LOGI(TAG, "BME680 chip found and initialized");
+  } else
+    ESP_LOGE(TAG, "BME680 chip not found on i2c bus");
+}
 
-  // read loop
+bool bme_read(void) {
-  while (1) {
+  bool ret = bme.performReading();
-
+  if (ret) {
-    vTaskDelay(10000 / portTICK_PERIOD_MS);
-
-    if (!bme.performReading()) {
-      ESP_LOGE(TAG, "BME680 read error");
-      continue;
-    } else {
     // read current BME data and buffer in global struct
-      bme_status.temperature = bme.temperature;
+    bme_status.temperature = (uint16_t)(bme.temperature * 100.0);
-      bme_status.pressure = bme.pressure / 100.0;
+    bme_status.pressure = (uint16_t)(bme.pressure / 100.0);
-      bme_status.humidity = bme.humidity;
+    bme_status.humidity = (uint8_t)bme.humidity;
-      bme_status.gas_resistance = bme.gas_resistance / 1000.0;
+    bme_status.gas_resistance = (uint16_t)(bme.gas_resistance / 1000.0);
-      bme_status.altitude = bme.readAltitude(SEALEVELPRESSURE_HPA);
+    bme_status.altitude =
+        (uint16_t)(bme.readAltitude(SEALEVELPRESSURE_HPA / 1000.0));
+    ESP_LOGI(TAG, "BME680 sensor data read success");
+  } else {
+    ESP_LOGI(TAG, "BME680 sensor read error");
   }
-  } // end of infinite loop
+  return ret;
-
+}
-  vTaskDelete(NULL); // shoud never be reached
-
-} // bme_loop()
 
 #endif // HAS_BME

src/cyclic.cpp

@@ -32,6 +32,11 @@ void doHousekeeping() {
   }
 #endif
 
+#ifdef HAS_BME
+  // read BME280 sensor if present
+  bme_read();
+#endif
+
   // task storage debugging //
   ESP_LOGD(TAG, "Wifiloop %d bytes left",
            uxTaskGetStackHighWaterMark(wifiSwitchTask));

src/hal/heltec.h

@@ -3,6 +3,8 @@
 
 #include <stdint.h>
 
+//#define HAS_BME 1  // BME680 sensor on I2C bus (SDI=21/SCL=22); comment out if not present
+
 // Hardware related definitions for Heltec LoRa-32 Board
 #define HAS_LORA 1       // comment out if device shall not send data via LoRa
 #define CFG_sx1276_radio 1

src/hal/ttgov21new.h

@@ -8,6 +8,8 @@
 // This settings are for boards labeled v1.6 on pcb, NOT for v1.5 or older
 */
 
+//#define HAS_BME 1  // BME680 sensor on I2C bus (SDI=21/SCL=22); comment out if not present
+
 #define HAS_LORA 1       // comment out if device shall not send data via LoRa
 #define CFG_sx1276_radio 1 // HPD13A LoRa SoC
 

src/lorawan.cpp

@@ -422,14 +422,14 @@ void user_request_network_time_callback(void *pVoidUserUTCTime,
   lmic_time_reference_t lmicTimeReference;
 
   if (flagSuccess != 1) {
-    ESP_LOGW(TAG, "Network time request callback error");
+    ESP_LOGW(TAG, "LoRaWAN network did not answer time request");
     return;
   }
 
   // Populate lmic_time_reference
   flagSuccess = LMIC_getNetworkTimeReference(&lmicTimeReference);
   if (flagSuccess != 1) {
-    ESP_LOGW(TAG, "Network time request failed");
+    ESP_LOGW(TAG, "LoRaWAN time request failed");
     return;
   }
 

src/main.cpp

@@ -35,7 +35,6 @@ IDLE          0     0     ESP32 arduino scheduler -> runs wifi sniffer
 looptask      1     1     arduino core -> runs the LMIC LoRa stack
 irqhandler    1     1     executes tasks triggered by irq
 gpsloop       1     2     reads data from GPS over serial or i2c
-bmeloop       1     2     reads data from BME680 over i2c
 IDLE          1     0     ESP32 arduino scheduler
 
 ESP32 hardware timers
@@ -56,7 +55,8 @@ uint8_t volatile channel = 0;              // channel rotation counter
 uint16_t volatile macs_total = 0, macs_wifi = 0, macs_ble = 0,
                   batt_voltage = 0; // globals for display
 
-hw_timer_t *channelSwitch = NULL, *sendCycle = NULL, *homeCycle = NULL, *displaytimer = NULL; // irq tasks
+hw_timer_t *channelSwitch = NULL, *sendCycle = NULL, *homeCycle = NULL,
+           *displaytimer = NULL; // irq tasks
 TaskHandle_t irqHandlerTask, wifiSwitchTask;
 
 std::set<uint16_t> macs; // container holding unique MAC adress hashes
@@ -161,6 +161,7 @@ void setup() {
 // initialize gps
 #ifdef HAS_BME
   strcat_P(features, " BME");
+  bme_init();
 #endif
 
 // initialize LoRa
@@ -281,17 +282,6 @@ void setup() {
                           1);        // CPU core
 #endif
 
-#ifdef HAS_BME
-  ESP_LOGI(TAG, "Starting BMEloop...");
-  xTaskCreatePinnedToCore(bme_loop,  // task function
-                          "bmeloop", // name of task
-                          2048,      // stack size of task
-                          (void *)1, // parameter of the task
-                          2,         // priority of the task
-                          &BmeTask,  // task handle
-                          1);        // CPU core
-#endif
-
   // start state machine
   ESP_LOGI(TAG, "Starting IRQ Handler...");
   xTaskCreatePinnedToCore(irqHandler,      // task function

src/paxcounter.conf

@@ -59,6 +59,7 @@
 #define LPP1PORT                        1       // Port for Cayenne LPP 1.0 dynamic sensor encoding
 #define LPP2PORT                        2       // Port for Cayenne LPP 2.0 packed sensor encoding
 #define BEACONPORT                      6       // Port on which device sends beacon alarms
+#define BMEPORT                         7       // Port on which device sends BME680 sensor data
 
 // Some hardware settings
 #define RGBLUMINOSITY                   30      // RGB LED luminosity [default = 30%]

src/payload.cpp

@@ -95,11 +95,15 @@ void PayloadConvert::addGPS(gpsStatus_t value) {
 
 void PayloadConvert::addBME(bmeStatus_t value) {
 #ifdef HAS_BME
-  buffer[cursor++] = (byte)(value.temperature);
+  buffer[cursor++] = highByte(value.temperature);
-  buffer[cursor++] = (byte)(value.pressure);
+  buffer[cursor++] = lowByte(value.temperature);
+  buffer[cursor++] = highByte(value.pressure);
+  buffer[cursor++] = lowByte(value.pressure);
   buffer[cursor++] = (byte)(value.humidity);
-  buffer[cursor++] = (byte)(value.gas_resistance);
+  buffer[cursor++] = highByte(value.gas_resistance);
-  buffer[cursor++] = (byte)(value.altitude);
+  buffer[cursor++] = lowByte(value.gas_resistance);
+  buffer[cursor++] = highByte(value.altitude);
+  buffer[cursor++] = lowByte(value.altitude);
 #endif
 }
 
@@ -162,11 +166,11 @@ void PayloadConvert::addGPS(gpsStatus_t value) {
 
 void PayloadConvert::addBME(bmeStatus_t value) {
 #ifdef HAS_BME
-  writeUint8((byte)value.temperature);
+  writeUint16(value.temperature);
-  writeUint8((byte)value.pressure);
+  writeUint16(value.pressure);
-  writeUint8((byte)value.humidity);
+  writeUint8(value.humidity);
-  writeUint8((byte)value.gas_resistance);
+  writeUint16(value.gas_resistance);
-  writeUint8((byte)value.altitude);
+  writeUint16(value.altitude);
 #endif
 }
 

src/rcommand.cpp

@@ -240,6 +240,17 @@ void get_gps(uint8_t val[]) {
 #endif
 };
 
+void get_bme(uint8_t val[]) {
+  ESP_LOGI(TAG, "Remote command: get bme680 sensor data");
+#ifdef HAS_BME
+  payload.reset();
+  payload.addBME(bme_status);
+  SendData(BMEPORT);
+#else
+  ESP_LOGW(TAG, "BME680 sensor not supported");
+#endif
+};
+
 // assign previously defined functions to set of numeric remote commands
 // format: opcode, function, #bytes params,
 // flag (true = do make settings persistent / false = don't)
@@ -255,7 +266,8 @@ cmd_t table[] = {
     {0x0f, set_wifiant, 1, true},       {0x10, set_rgblum, 1, true},
     {0x11, set_monitor, 1, true},       {0x12, set_beacon, 7, false},
     {0x80, get_config, 0, false},       {0x81, get_status, 0, false},
-    {0x84, get_gps, 0, false}};
+    {0x84, get_gps, 0, false},          {0x85, get_bme, 0, false},
+};
 
 const uint8_t cmdtablesize =
     sizeof(table) / sizeof(table[0]); // number of commands in command table