CO2 readout

Hi folks,

Let me first explain the objective. Through an Arduino do I like to read on an LCD the 0-5VDC signal coming from a CO2 sensor but scaled with 0V is 0.00% and 5V is 3,00%.
Next step is doing data logging of this value to an SD card

I have following hardware:

The CO2 sensor is powered by a separate 24VDC power supply with the (-) of this sensor connected to (-) of the 12VDC power supply for the Arduino.
The signal is connected to the analog input 1
Both libraries (lcd display and data logger shield) is installed.

Can somebody provide some links to a similar project please?
Also the code for averaging the readout value is highly appreciated.

Thank you already for the help in this.

Can somebody provide some links to a similar project please?

Can I suggest you either use the search box on the top right corner of this web site or ask Mr. Google or one of his friends? By asking what you are asking you are basically asking us to do the search for you.

Assuming your 5V supply is stable at 5.00V you can use this to get your percent:

float percent =  (analogRead(CO2SensorPin) * 3.00) / 1024.0);

The rest of the code comes from the examples for the logging shield and LCD shield libraries.