For a school project I had to use a co2 sensor to measure the co2 in a room, for this I used the parallax 27929 co2 gas sensor, but once I wired it up it didn't give any values back to arduino.
This is my wiring: Imgur: The magic of the Internet
Is there any problem with it, or is it the sensor that's broken?
Throw your code up for people to inspect... It could be an issue with that.
Also, is the red led on?
james13:
Throw your code up for people to inspect... It could be an issue with that.Also, is the red led on?
It is on, we can't get it off by screwing on it and making the value of which it goes on / off lower / higher.
As for the code, it's giving the 5v input 5v and it just reads value. According to someone here nothing was wrong with it.
According to the Datasheet
| CNTL | Heat switch input from microcontroller, active HIGH | 0V – 12VDC |
|---|---|---|
| ALM | Alarm output to host microcontroller, active HIGH | 0V / 3.3V |
| VIN | Heat switch input from microcontroller, active HIGH | 0V – 12VDC |
The Control input needs to be quite high (12V) but if it's only getting 5V that may not be quite enough. However if you can change the variable resistor to turn the light on / offf then that suggest your input voltage is ok.
The Alarm output only gives out 3.3V - the Uno may not read that as high so you may need a logic converter to get a 5V high.
Sorry I can't recall what the high level trigger is...
Have you tested it with C02?