I set up my CO2 engine of the type K33 ICB-F once with analogue output (working just fine) and once with the UART where I cannot figure out what I am doing wrong. I am reading the signal with an Arduino Nano and I always receive the same value of CO2 ppm = 8304. When checking with my multimeter, I see no voltage change on my TX pin at my CO2 engine so apparently there is no signal being sent. What am I doing wrong?
Here is my hardware setup:
My Arduino code I took from an (Instructable) and it looks like this:
// AN-126 Demo of K-30 using Software Serial
#include <SoftwareSerial.h>
/*
Basic Arduino example for K-Series sensor
Created by Jason Berger
Co2meter.com
*/
#include "SoftwareSerial.h"
SoftwareSerial K_30_Serial(1,0); //Sets up a virtual serial port
byte readCO2[] = {0xFE, 0X44, 0X00, 0X08, 0X02, 0X9F, 0X25}; //Command packet to read Co2 (see app note)
byte response[] = {0,0,0,0,0,0,0}; //create an array to store the response
//multiplier for value. default is 1. set to 3 for K-30 3% and 10 for K-33 ICB
int valMultiplier = 1;
void setup()
{
// put your setup code here, to run once:
Serial.begin(9600); //Opens the main serial port to communicate with the computer
K_30_Serial.begin(9600); //Opens the virtual serial port with a baud of 9600
Serial.println(" Demo of AN-126 Software Serial and K-40 Sensor");
}
void loop()
{
sendRequest(readCO2);
unsigned long valCO2 = getValue(response);
Serial.print("Co2 ppm = ");
Serial.println(valCO2);
delay(2000);
}
void sendRequest(byte packet[])
{
while(!K_30_Serial.available()) //keep sending request until we start to get a response
{
Serial.println("waiting for Software.serial port availability");
K_30_Serial.write(readCO2,7);
delay(50);
}
int timeout=0; //set a timeout counter
while(K_30_Serial.available() < 7 ) //Wait to get a 7 byte response
{
timeout++;
if(timeout > 10) //if it takes too long there was probably an error
{
while(K_30_Serial.available()) //flush whatever we have
K_30_Serial.read();
break; //exit and try again
}
delay(50);
}
for (int i=0; i < 7; i++)
{
response[i] = K_30_Serial.read();
}
}
unsigned long getValue(byte packet[])
{
int high = packet[3]; //high byte for value is 4th byte in packet in the packet
int low = packet[4]; //low byte for value is 5th byte in the packet
unsigned long val = high*256 + low; //Combine high byte and low byte with this formula to get value
return val* valMultiplier;
}
