First project: CO2 and Temperature with Arduino Nano

Projects Programming
19

wow, that actually fixed the display problem! it is working now with the example from adafruit!
I already tried going to the next step, getting the CO2 Sensor running and yet again facing issues...
After googling for a long time someone mentioned that possibly the Arduino does not supply enough power, so I hooked the sensor up to a buck converter, which did not help.
Actually there seem to be only two cables that need to be connected to the Arduino: the TX and RX. Since you gave the advice of running the example first, I tried that with the CO2 sensor too.
I connected the parts like this, so buck converter to CO2 for energy, CO2 to Arduino for data (TX to D5, RX to D6

[Album] imgur.com

The example code is actually very short:

#include <Arduino.h>
#include "MHZ19.h"                                        
#include <SoftwareSerial.h>                                // Remove if using HardwareSerial

#define RX_PIN 6                                      // Rx pin which the MHZ19 Tx pin is attached to
#define TX_PIN 5                                         // Tx pin which the MHZ19 Rx pin is attached to
#define BAUDRATE 9600                                      // Device to MH-Z19 Serial baudrate (should not be changed)

MHZ19 myMHZ19;                                             // Constructor for library
SoftwareSerial mySerial(RX_PIN, TX_PIN);                   // (Uno example) create device to MH-Z19 serial

unsigned long getDataTimer = 0;

void setup()
{
    Serial.begin(9600);                                     // Device to serial monitor feedback

    mySerial.begin(BAUDRATE);                               // (Uno example) device to MH-Z19 serial start   
    myMHZ19.begin(mySerial);                                // *Serial(Stream) refence must be passed to library begin(). 

    myMHZ19.autoCalibration();                              // Turn auto calibration ON (OFF autoCalibration(false))
}

void loop()
{
    if (millis() - getDataTimer >= 2000)
    {
        int CO2; 

        /* note: getCO2() default is command "CO2 Unlimited". This returns the correct CO2 reading even 
        if below background CO2 levels or above range (useful to validate sensor). You can use the 
        usual documented command with getCO2(false) */

        CO2 = myMHZ19.getCO2();                             // Request CO2 (as ppm)
        
        Serial.print("CO2 (ppm): ");                      
        Serial.println(CO2);                                

        int8_t Temp;
        Temp = myMHZ19.getTemperature();                     // Request Temperature (as Celsius)
        Serial.print("Temperature (C): ");                  
        Serial.println(Temp);                               

        getDataTimer = millis();
    }
}

but the output is just errors:
!ERROR: Failed to verify connection(1) to sensor.
!ERROR: Initial communication errorCode recieved
!Error: Timed out waiting for response
!Warning: Clearing Byte: 255
!Error: Timed out waiting for response