Extracted MHZ logic into its own class.

MH-Z19B.ino

@@ -1,110 +1,35 @@
+
+
+#include <SoftwareSerial.h>
+#include <ESP8266WiFi.h>
+#include "MHZ.h"
+
 #define CO2_IN D2
 
 #define MH_Z19_RX D7
 #define MH_Z19_TX D6
 
-#include <SoftwareSerial.h>
-SoftwareSerial co2Serial(MH_Z19_RX, MH_Z19_TX); // define MH-Z19 RX TX
+
+MHZ co2(MH_Z19_RX, MH_Z19_TX, CO2_IN, MHZ19B);
 
 unsigned long startTime = millis();
 
+
 void setup() {
   Serial.begin(9600);
-  co2Serial.begin(9600);
   pinMode(CO2_IN, INPUT);
+  delay(100);
+  Serial.println("MHZ 19B");
 }
 
+
 void loop() {
   Serial.print("Time from start: ");
   Serial.print((millis() - startTime) / 1000);
   Serial.println(" s");
-  int ppm_uart = readCO2UART();
-  int ppm_pwm = readCO2PWM();
+  int ppm_uart = co2.readCO2UART();
+  int ppm_pwm = co2.readCO2PWM();
 
   Serial.println("\n------------------------------");
   delay(5000);
 }
-
-int readCO2UART() {
-  Serial.println("-- read CO2 uart ---");
-  byte cmd[9] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79};
-  byte response[9]; // for answer
-
-  Serial.println("Sending CO2 request...");
-  co2Serial.write(cmd, 9); //request PPM CO2
-
-  // clear the buffer
-  memset(response, 0, 9);
-  int i = 0;
-  while (co2Serial.available() == 0) {
-    //    Serial.print("Waiting for response ");
-    //    Serial.print(i);
-    //    Serial.println(" s");
-    delay(1000);
-    i++;
-  }
-  if (co2Serial.available() > 0) {
-    co2Serial.readBytes(response, 9);
-  }
-  // print out the response in hexa
-  for (int i = 0; i < 9; i++) {
-    Serial.print(String(response[i], HEX));
-    Serial.print("   ");
-  }
-  Serial.println("");
-
-  // checksum
-  byte check = getCheckSum(response);
-  if (response[8] != check) {
-    Serial.println("Checksum not OK!");
-    Serial.print("Received: ");
-    Serial.println(response[8]);
-    Serial.print("Should be: ");
-    Serial.println(check);
-  }
-
-  // ppm
-  int ppm_uart = 256 * (int)response[2] + response[3];
-  Serial.print("PPM UART: ");
-  Serial.println(ppm_uart);
-
-  // temp
-  byte temp = response[4] - 40;
-  Serial.print("Temperature? ");
-  Serial.println(temp);
-
-  // status
-  byte status = response[5];
-  Serial.print("Status? ");
-  Serial.println(status);
-  if (status == 0x40) {
-    Serial.println("Status OK");
-  }
-
-  return ppm_uart;
-}
-
-byte getCheckSum(byte *packet) {
-  Serial.println("-- get checksum ---");
-  byte i;
-  unsigned char checksum = 0;
-  for (i = 1; i < 8; i++) {
-    checksum += packet[i];
-  }
-  checksum = 0xff - checksum;
-  checksum += 1;
-  return checksum;
-}
-
-int readCO2PWM() {
-  Serial.println("-- read CO2 pwm ---");
-  unsigned long th, tl, ppm_pwm = 0;
-  do {
-    th = pulseIn(CO2_IN, HIGH, 1004000) / 1000;
-    tl = 1004 - th;
-    ppm_pwm = 5000 * (th - 2) / (th + tl - 4);
-  } while (th == 0);
-  Serial.print("PPM PWM: ");
-  Serial.println(ppm_pwm);
-  return ppm_pwm;
-}

MHZ.cpp

@@ -1,69 +1,25 @@
+/* MHZ library
 
-#include <SoftwareSerial.h>
+    By Tobias Schürg
+*/
 
-// include the library code:
-#include <LiquidCrystal.h>
+#include "MHZ.h"
 
-// initialize the library with the numbers of the interface pins
-LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
 
-SoftwareSerial co2Serial(7, 6); // define MH-Z19 RX TX
-unsigned long startTime = millis();
+MHZ:: MHZ(uint8_t rxpin, uint8_t txpin, uint8_t pwmpin, uint8_t type)
+  : co2Serial(rxpin, txpin)
+{
+  _rxpin = rxpin;
+  _txpin = txpin;
+  _pwmpin = pwmpin;
+  _type = type;
 
-void setup() {
-  Serial.begin(9600);
   co2Serial.begin(9600);
-  pinMode(9, INPUT);
-
-  // set up the LCD's number of columns and rows:
-  lcd.begin(16, 2);
-  lcd.print("CO2 heating up");
-
-  lcd.setCursor(4, 1);
-  lcd.print("seconds left");
-
-  for (int seconds = 180; seconds > 0; seconds--) {
-    lcd.setCursor(0, 1);
-    lcd.print("   "); // clear timer
-    lcd.setCursor(0, 1);
-    lcd.print(seconds);
-    delay(1000);
-  }
-
-  lcd.clear();
-  lcd.setCursor(0, 0);
-  lcd.print("CO2 Air Quality");
 }
 
-void loop() {
-  Serial.println("------------------------------");
-  Serial.print("Time from start: ");
-  Serial.print((millis() - startTime) / 1000);
-  Serial.println(" s");
-  int ppm_uart = readCO2UART();
-  int ppm_pwm = readCO2PWM();
 
-  // TODO: just clear second line?
-  lcd.clear();
-  lcd.setCursor(0, 0);
-  lcd.print("CO2 Air Quality");
-
-  lcd.setCursor(0, 1);
-  lcd.print("PPM: ");
-
-  lcd.setCursor(5, 1);
-  lcd.print(ppm_pwm);
-
-  lcd.setCursor(10, 1);
-  lcd.print("|");
-
-  lcd.setCursor(12, 1);
-  lcd.print(ppm_uart);
-
-  delay(5000);
-}
-
-int readCO2UART() {
+int MHZ::readCO2UART() {
+  Serial.println("-- read CO2 uart ---");
   byte cmd[9] = {0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79};
   byte response[9]; // for answer
 
@@ -121,7 +77,8 @@ int readCO2UART() {
   return ppm_uart;
 }
 
-byte getCheckSum(char *packet) {
+byte MHZ::getCheckSum(byte *packet) {
+  Serial.println("-- get checksum ---");
   byte i;
   unsigned char checksum = 0;
   for (i = 1; i < 8; i++) {
@@ -132,10 +89,12 @@ byte getCheckSum(char *packet) {
   return checksum;
 }
 
-int readCO2PWM() {
+int MHZ::readCO2PWM() {
+  Serial.println("-- read CO2 pwm ---");
   unsigned long th, tl, ppm_pwm = 0;
   do {
-    th = pulseIn(9, HIGH, 1004000) / 1000;
+    Serial.print(".");
+    th = pulseIn(_pwmpin, HIGH, 1004000) / 1000;
     tl = 1004 - th;
     ppm_pwm = 5000 * (th - 2) / (th + tl - 4);
   } while (th == 0);

MHZ.h

@@ -0,0 +1,39 @@
+/* MHZ library
+
+    By Tobias Schürg
+*/
+#ifndef MHZ_H
+#define MHZ_H
+
+#if ARDUINO >= 100
+#include "Arduino.h"
+#else
+#include "WProgram.h"
+#endif
+
+
+// Define types of sensors.
+#define MHZ14A 14
+#define MHZ19B 19
+
+
+#include <SoftwareSerial.h>
+
+
+class MHZ {
+  public:
+    MHZ(uint8_t rxpin, uint8_t txpin, uint8_t pwmpin, uint8_t type);
+
+    int readCO2UART();
+    int readCO2PWM();
+
+  private:
+    uint8_t _rxpin, _txpin, _pwmpin, _type;
+    SoftwareSerial co2Serial;
+    byte getCheckSum(byte *packet);
+
+};
+
+
+#endif
+