Issues with CO2 sensor SEN0159 I followed the sketch example for the SEN0159 CO2 sensor as precised in the data sheet  https://www.dfrobot.com/wiki/index.php/CO2_Sensor_SKU:SEN0159. It's powered by a 9V/2A DC power supply more than 48h and it still reads 2.81V on the analog ouput pin even if i exhaust on the sensor during long time, nothing happen, giving - 1ppm CO2 value. 

Can you explain me why i cannot observe CO2 variations ? Is there troubles with the board ?

Thanks!
Yes, i made a mistake... The arduino board should be powered by a 7-12V power supply to support high current from 5V pinout in order to power the sensor card... I'm very lucky, my sensor is not broken. I have powered it with 5V and it works fine!!! Thanks