Design and build a device for detecting relative amounts of carbon dioxide (CO2) gas. Test one variable in order to increase the effectiveness of the device....Which safe tests are available for demonstrating the presence of CO2?What kind of device could be used to get a measurement of CO2 levels?
"please give me a solution".
A solution would be ideal.
you could measure the change in opacity with a photo-resistor...
Arduino has a gas sensor that can detect many types of gasses.
Yes, it would be ideal. I just don't want people "yelling" at me for just asking for the solution,
If you're going to do this optically, don't forget to put in a reference detector, to account for variations in the intensity of the light source.Old CD or DVD drives are good sources of beam-splitters.
But, if the change is so subtle, and I am only turning the flashlight on a few seconds at a time, I don't think that the LDR will pick it up, and it can be ignored.
The limewater hack will help you detect AMOUNT of CO2 (in particular, the amount of CO2 that you manage to put into solution, which is not quite the same thing), but I don't think it would be very good at distinguishing different concentrations.