add bme280

lib/MQ135/MQ135.cpp

@@ -3,13 +3,10 @@
 @file     MQ135.cpp
 @author   G.Krocker (Mad Frog Labs)
 @license  GNU GPLv3
-
 First version of an Arduino Library for the MQ135 gas sensor
 TODO: Review the correction factor calculation. This currently relies on
 the datasheet but the information there seems to be wrong.
-
 @section  HISTORY
-
 v1.0 - First release
 */
 /**************************************************************************/
@@ -19,7 +16,6 @@ v1.0 - First release
 /**************************************************************************/
 /*!
 @brief  Default constructor
-
 @param[in] pin  The analog input pin for the readout of the sensor
 */
 /**************************************************************************/
@@ -32,10 +28,8 @@ MQ135::MQ135(uint8_t pin) {
 /**************************************************************************/
 /*!
 @brief  Get the correction factor to correct for temperature and humidity
-
 @param[in] t  The ambient air temperature
 @param[in] h  The relative humidity
-
 @return The calculated correction factor
 */
 /**************************************************************************/
@@ -46,7 +40,6 @@ float MQ135::getCorrectionFactor(float t, float h) {
 /**************************************************************************/
 /*!
 @brief  Get the resistance of the sensor, ie. the measurement value
-
 @return The sensor resistance in kOhm
 */
 /**************************************************************************/
@@ -59,10 +52,8 @@ float MQ135::getResistance() {
 /*!
 @brief  Get the resistance of the sensor, ie. the measurement value corrected
         for temp/hum
-
 @param[in] t  The ambient air temperature
 @param[in] h  The relative humidity
-
 @return The corrected sensor resistance kOhm
 */
 /**************************************************************************/
@@ -73,7 +64,6 @@ float MQ135::getCorrectedResistance(float t, float h) {
 /**************************************************************************/
 /*!
 @brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
-
 @return The ppm of CO2 in the air
 */
 /**************************************************************************/
@@ -85,10 +75,8 @@ float MQ135::getPPM() {
 /*!
 @brief  Get the ppm of CO2 sensed (assuming only CO2 in the air), corrected
         for temp/hum
-
 @param[in] t  The ambient air temperature
 @param[in] h  The relative humidity
-
 @return The ppm of CO2 in the air
 */
 /**************************************************************************/
@@ -99,7 +87,6 @@ float MQ135::getCorrectedPPM(float t, float h) {
 /**************************************************************************/
 /*!
 @brief  Get the resistance RZero of the sensor for calibration purposes
-
 @return The sensor resistance RZero in kOhm
 */
 /**************************************************************************/
@@ -111,10 +98,8 @@ float MQ135::getRZero() {
 /*!
 @brief  Get the corrected resistance RZero of the sensor for calibration
         purposes
-
 @param[in] t  The ambient air temperature
 @param[in] h  The relative humidity
-
 @return The corrected sensor resistance RZero in kOhm
 */
 /**************************************************************************/

lib/MQ135/MQ135.h

@@ -25,7 +25,7 @@ v1.0 - First release
 #define RLOAD 10.0
 /// Calibration resistance at atmospheric CO2 level
 // #define RZERO 76.63
-#define RZERO 480
+#define RZERO 4000
 /// Parameters for calculating ppm of CO2 from sensor resistance
 #define PARA 116.6020682
 #define PARB 2.769034857

platformio.ini

@@ -8,7 +8,7 @@
 ; Please visit documentation for the other options and examples
 ; https://docs.platformio.org/page/projectconf.html
 
-[env:uno]
+[env:mega]
 platform = atmelavr
-board = uno
+board = megaatmega2560
 framework = arduino

src/main.cpp

@@ -1,10 +1,9 @@
 #include <Arduino.h>
 #include <MQ135.h>
-#include <dht.h>
+#include <Adafruit_Sensor.h>
+#include <Adafruit_BME280.h>
 
 #define PIN_MQ135 A0
-#define PIN_DHT11 A1
-
 #define PIN_LED_GREEN DD2
 #define PIN_LED_YELLOW DD3
 #define PIN_LED_RED DD4
@@ -13,74 +12,38 @@
 #define MEASURE_DELAY 1000
 #define NOISE_DELAY 100
 
+#define SEALEVELPRESSURE_HPA (1013.25)
+
 MQ135 co2_sensor = MQ135(PIN_MQ135);
-dht dht_sensor;
+Adafruit_BME280 bme(10, 11, 12, 13);
 const int maxCount = MEASURE_DELAY / NOISE_DELAY;
-int count = 0;
+int count = -1;
-float ppm = -1;
+float ppm = 0;
 bool noise = false;
 
 void setup() {
-  Serial.begin(9600);
   pinMode(PIN_MQ135, INPUT);
-  pinMode(PIN_DHT11, INPUT);
   pinMode(PIN_LED_GREEN, OUTPUT);
   pinMode(PIN_LED_YELLOW, OUTPUT);
   pinMode(PIN_LED_RED, OUTPUT);
   pinMode(PIN_NOISE, OUTPUT);
+
+  Serial.begin(9600);
+
+  if (!bme.begin()) {
+    Serial.println(F("Could not find a valid BME280 sensor, check wiring!"));
+  }
 }
 
-float measure() {
+void printValues();
-  Serial.print(RZERO);
-  Serial.println("---------------------------");
-  Serial.print("DHT:\t");
-  int chk = dht_sensor.read11(PIN_DHT11);
-  switch (chk)
-  {
-    case DHTLIB_OK:  
-      Serial.print("OK,\t"); 
-      break;
-    case DHTLIB_ERROR_CHECKSUM: 
-      Serial.print("Checksum error,\t"); 
-      break;
-    case DHTLIB_ERROR_TIMEOUT: 
-      Serial.print("Time out error,\t"); 
-      break;
-    case DHTLIB_ERROR_CONNECT:
-        Serial.print("Connect error,\t");
-        break;
-    case DHTLIB_ERROR_ACK_L:
-        Serial.print("Ack Low error,\t");
-        break;
-    case DHTLIB_ERROR_ACK_H:
-        Serial.print("Ack High error,\t");
-        break;
-    default: 
-      Serial.print("Unknown error,\t"); 
-      break;
-  }
-  Serial.println();
-
-  Serial.print ("temperature: ");
-  Serial.println (dht_sensor.temperature);
-  Serial.print ("humidity: ");
-  Serial.println (dht_sensor.humidity);
-
-  float val = analogRead(A0);
-  Serial.print ("raw = ");
-  Serial.println (val);
-  float zero = co2_sensor.getCorrectedRZero(dht_sensor.temperature, dht_sensor.humidity);
-  Serial.print ("rzero: ");
-  Serial.println (zero);
-  float ppm = co2_sensor.getCorrectedPPM(dht_sensor.temperature, dht_sensor.humidity);
-  Serial.print ("ppm: ");
-  Serial.println (ppm);
-  return ppm;
-}
 
 void loop() {
-  if (count >= maxCount || ppm < 0) {
+  if (count >= maxCount || count < 0) {
-    ppm = measure();
+    ppm = co2_sensor.getPPM();
+    Serial.print ("ppm: ");
+    Serial.println (ppm);
+    Serial.print ("rzero: ");
+    Serial.println (co2_sensor.getRZero());
     count = 0;
     if (ppm < 1000) {
       digitalWrite(PIN_LED_GREEN, 1);
@@ -97,6 +60,8 @@ void loop() {
       digitalWrite(PIN_LED_YELLOW, 0);
       digitalWrite(PIN_LED_RED, 1);
     }
+
+    // printValues();
   }
 
   if (ppm > 2000) {
@@ -110,3 +75,24 @@ void loop() {
   delay(NOISE_DELAY);
   count++;
 }
+
+void printValues() {
+  Serial.print("Temperature = ");
+  Serial.print(bme.readTemperature());
+  Serial.println(" *C");
+
+  Serial.print("Pressure = ");
+
+  Serial.print(bme.readPressure() / 100.0F);
+  Serial.println(" hPa");
+
+  Serial.print("Approx. Altitude = ");
+  Serial.print(bme.readAltitude(SEALEVELPRESSURE_HPA));
+  Serial.println(" m");
+
+  Serial.print("Humidity = ");
+  Serial.print(bme.readHumidity());
+  Serial.println(" %");
+
+  Serial.println();
+}

test/main.cpp

@@ -0,0 +1,112 @@
+#include <Arduino.h>
+#include <MQ135.h>
+#include <dht.h>
+
+#define PIN_MQ135 A0
+#define PIN_DHT11 A1
+
+#define PIN_LED_GREEN DD2
+#define PIN_LED_YELLOW DD3
+#define PIN_LED_RED DD4
+#define PIN_NOISE DD5
+
+#define MEASURE_DELAY 1000
+#define NOISE_DELAY 100
+
+MQ135 co2_sensor = MQ135(PIN_MQ135);
+dht dht_sensor;
+const int maxCount = MEASURE_DELAY / NOISE_DELAY;
+int count = 0;
+float ppm = -1;
+bool noise = false;
+
+void setup() {
+  Serial.begin(9600);
+  pinMode(PIN_MQ135, INPUT);
+  pinMode(PIN_DHT11, INPUT);
+  pinMode(PIN_LED_GREEN, OUTPUT);
+  pinMode(PIN_LED_YELLOW, OUTPUT);
+  pinMode(PIN_LED_RED, OUTPUT);
+  pinMode(PIN_NOISE, OUTPUT);
+}
+
+float measure() {
+  Serial.print(RZERO);
+  Serial.println("---------------------------");
+  Serial.print("DHT:\t");
+  int chk = dht_sensor.read11(PIN_DHT11);
+  switch (chk)
+  {
+    case DHTLIB_OK:  
+      Serial.print("OK,\t"); 
+      break;
+    case DHTLIB_ERROR_CHECKSUM: 
+      Serial.print("Checksum error,\t"); 
+      break;
+    case DHTLIB_ERROR_TIMEOUT: 
+      Serial.print("Time out error,\t"); 
+      break;
+    case DHTLIB_ERROR_CONNECT:
+        Serial.print("Connect error,\t");
+        break;
+    case DHTLIB_ERROR_ACK_L:
+        Serial.print("Ack Low error,\t");
+        break;
+    case DHTLIB_ERROR_ACK_H:
+        Serial.print("Ack High error,\t");
+        break;
+    default: 
+      Serial.print("Unknown error,\t"); 
+      break;
+  }
+  Serial.println();
+
+  Serial.print ("temperature: ");
+  Serial.println (dht_sensor.temperature);
+  Serial.print ("humidity: ");
+  Serial.println (dht_sensor.humidity);
+
+  float val = analogRead(A0);
+  Serial.print ("raw = ");
+  Serial.println (val);
+  float zero = co2_sensor.getCorrectedRZero(dht_sensor.temperature, dht_sensor.humidity);
+  Serial.print ("rzero: ");
+  Serial.println (zero);
+  float ppm = co2_sensor.getCorrectedPPM(dht_sensor.temperature, dht_sensor.humidity);
+  Serial.print ("ppm: ");
+  Serial.println (ppm);
+  return ppm;
+}
+
+void loop() {
+  if (count >= maxCount || ppm < 0) {
+    ppm = measure();
+    count = 0;
+    if (ppm < 1000) {
+      digitalWrite(PIN_LED_GREEN, 1);
+      digitalWrite(PIN_LED_YELLOW, 0);
+      digitalWrite(PIN_LED_RED, 0);
+    }
+    else if (ppm <= 2000) {
+      digitalWrite(PIN_LED_GREEN, 0);
+      digitalWrite(PIN_LED_YELLOW, 1);
+      digitalWrite(PIN_LED_RED, 0);
+    }
+    else {
+      digitalWrite(PIN_LED_GREEN, 0);
+      digitalWrite(PIN_LED_YELLOW, 0);
+      digitalWrite(PIN_LED_RED, 1);
+    }
+  }
+
+  if (ppm > 2000) {
+    noise = !noise;
+    digitalWrite(PIN_NOISE, noise);
+  }
+  else {
+    digitalWrite(PIN_NOISE, 0);
+  }
+
+  delay(NOISE_DELAY);
+  count++;
+}