Arduino Seeeduino Stalker v2.3 unable to read I2C Tongdy CO2

CO2 sensor K30. I have read using I2C using UNO board. Successful. Code is attached.
A4 connect to I2c data. A5 to I2C clock.

PROBLEM: when using Seeeduino Stalker V2.3
I cant read CO@ anymore.
Code is attached.

I need advice

Thank you

…Ahmad

///////////////////////// start code
#include <Wire.h>
int co2Addr = 0x68; // DEFAULT Address of the CO2 sensor, 7bits shifted left.

void setup()
{ Serial.begin(9600); // Open serial connection to report values to host
Wire.begin();
Serial.println(“Start…”);
delay(2000);
}

int readCO2()
{ int co2_value = 0; // We will store the CO2 value inside this variable.
Wire.beginTransmission(co2Addr); // Comm through i2c
Wire.write(0x22);
Wire.write(0x00);
Wire.write(0x08); // CO2
Wire.write(0x2A); // CO2
Wire.endTransmission(co2Addr);
delay(10);
Wire.requestFrom(co2Addr, 4);
byte i = 0;
byte buffer[4] = {0, 0, 0, 0};
while(Wire.available())
{ buffer = Wire.read();
i++;
}
co2_value = 0;
co2_value |= buffer[1] & 0xFF;
co2_value = co2_value << 8;
co2_value |= buffer[2] & 0xFF;
byte sum = 0; //Checksum Byte
sum = buffer[0] + buffer[1] + buffer[2]; //Byte addition utilizes overflow
if(sum == buffer[3])
{ // if ok Success!
digitalWrite(13, LOW);
return co2_value;
}
else
{ // if fail
digitalWrite(13, LOW);
return 0;
}
}

void loop()
{ int co2Value ;
delay(1000);
co2Value = readCO2();
delay(1000);
if(co2Value > 0)
{ // if ok
Serial.print("xCO2 Value: “);
Serial.print(co2Value);
Serial.println(” ");
}
else
{ Serial.println(“Chksum/Commfail”); }
delay(2000);
}
////////////////////end code

The address of CO2 0x68 is the same of RTC of Stalker, so you can’t use CO2 sensor with Stalker or maybe change the address of CO2.

Good luck.