Looks hard to interface to. You have to cycle power to the heater 60 seconds at 5v and 90 seconds at 1.4v and repeat that for 48 hours before you can rely on the readings?!?
I have done that over a 48 hour period, my concern is that I am using PWM to generate the 1.4v, which I am not convinced is working....perhaps the Arduino cannot supply the mA needed?
I don't think you can determine ppm CO. The resistance at 100ppm can be anywhere from 2k to 20K and the signal you get is the ratio of that resistance and the current resistance.
As near as I can tell from the charts: if the resistance drops to 1/28th the resistance in clean air you probably have about 100ppm and 1/280th would put it at about 4000ppm
Sorry my electronics isn't great. If I have a 10k resistor between the output of the sensor (B1) and ground, and then I put an analogRead on (B1) also, then the reading I get is around the 800 mark. How do I translate this to the ratio?
[quote author=Terry King link=topic=55799.msg400001#msg400001 date=1300515063]
Interesting problem... I used some of these MANY years ago (I believe they are basically "Taguchi Gas Sensors" Google and you'll see a lot of information is available.
Please keep us informed of what you find out. I am buying some of these out of China and I want to have an Arduino page showing how to use them!
Yes from Googling (verb?) I would agree that's what it looks like. These are from Sparkfun, but seem very similar to the Figaro sensors available, which would make sense given the information you posted.
My plan is to basically make a circuit to power an array of various sensors, then use the Arduino Duemilanova with analog reads to take the readings and pass them along a serial interface.
Any help appreciated!