Looking for a sketch for mh-z19 co2 sensor

Other Hardware Sensors
1

Just had a sensor delivered to eventually do a air quality project, currently working on another project at the moment. All the sketches i have tried involve other bits of equipment like wifi, or a display of some sorts. As i'm still quite new to all of this me chopping bits out of the sketch isn't working as i hoped. Hoping someone might know of a sketch where i can view the working through serial monitor in the ide?

Regards

2

Ok my need to find something final came up trumps at 0230, thanks to the good old Russians. If anyone else is looking for a simple test sketch this is it. Note that the TX & RX go to analog 0&1.

3

rx en tx on a0,a1 5v ,gnd

#include <SoftwareSerial.h>;

SoftwareSerial mySerial(A0, A1); // connect also co2sensor-ardunoUno17 with  Tx-A0,Rx-A1,Vin-5v,GND-GND  ,Old bootloader in my case

byte cmd[9] = {0xFF,0x01,0x86,0x00,0x00,0x00,0x00,0x00,0x79}; 
unsigned char response[9];

void setup() {
  Serial.begin(9600);
  mySerial.begin(9600);
}

void loop() 
{
  mySerial.write(cmd, 9);
  memset(response, 0, 9);
  mySerial.readBytes(response, 9);
  int i;
  byte crc = 0;
  for (i = 1; i < 8; i++) crc+=response[i];
  crc = 255 - crc;
  crc++;

   if ( !(response[0] == 0xFF && response[1] == 0x86 && response[8] == crc) ) {
    Serial.println("CRC error: " + String(crc) + " / "+ String(response[8]));
  } else {
    unsigned int responseHigh = (unsigned int) response[2];
    unsigned int responseLow = (unsigned int) response[3];
    unsigned int ppm = (256*responseHigh) + responseLow;
    Serial.println(ppm);
  }
  delay(10000);
}
4

The idea is to write code and learn from it ! Saves you a couple of years ??

5

hammy:
The idea is to write code and learn from it ! Saves you a couple of years ??

When the trolls have to self isolate and have nothing else better to do.

6

fritssluijter:
rx en tx on a0,a1 5v ,gnd

#include <SoftwareSerial.h>;

SoftwareSerial mySerial(A0, A1); // connect also co2sensor-ardunoUno17 with  Tx-A0,Rx-A1,Vin-5v,GND-GND  ,Old bootloader in my case

byte cmd[9] = {0xFF,0x01,0x86,0x00,0x00,0x00,0x00,0x00,0x79};
unsigned char response[9];

void setup() {
  Serial.begin(9600);
  mySerial.begin(9600);
}

void loop()
{
  mySerial.write(cmd, 9);
  memset(response, 0, 9);
  mySerial.readBytes(response, 9);
  int i;
  byte crc = 0;
  for (i = 1; i < 8; i++) crc+=response[i];
  crc = 255 - crc;
  crc++;

if ( !(response[0] == 0xFF && response[1] == 0x86 && response[8] == crc) ) {
    Serial.println("CRC error: " + String(crc) + " / "+ String(response[8]));
  } else {
    unsigned int responseHigh = (unsigned int) response[2];
    unsigned int responseLow = (unsigned int) response[3];
    unsigned int ppm = (256*responseHigh) + responseLow;
    Serial.println(ppm);
  }
  delay(10000);
}

Thank you, I did find a sketch a few years ago after creating the thread, never did get around to posting it. Just a link.

Regards