Environment Parameter Monitoring System
14micc11 wrote 07/25/2015 at 05:45 • 1 pointI will be using sensor MiCS-6814 for measuring concentration of gases. So how to interface with microcontroller and how is the working of sensor.
I have downloaded the datasheet but i have few queries like,
1. I got the circuit of interfacing from data sheet. In that circuit there are three NH3 ,NO2 & CO value that we are getting on pin number D,A and H respectively. So my question is what type of output value we are getting on that corresponding pins D, A and H? If we are getting change is resistance then how to decide the value of voltage divider resistors for the measurement.
2. Sensor MiCS-6814 has two circuit i.e preheating circuit and measurement circuit. So my question is that we have to make individual circuit for both pre heating and measurement circuit or it can be integrated as one circuit and will be able to measure the concentration?
3. For much time i have to pre-heat my MiCS-6814 sensor?
4. What is the standard value for resistance R0 in air for CO, NH3 & NO2?
5. Why three resistors as RL1, RL2 and RL3 are needed?
Discussions
Become a Hackaday.io Member
Create an account to leave a comment. Already have an account? Log In.
Ok Peter Sir got it. So Peter Sir i want suggestion on whether to buy this sensor or not for my project or you have any suggestion for any other good gas sensor whcih measure CO,NO2 and NH3?
Are you sure? yes | no
These are all good questions, and (from memory) the datasheet for the MiCS-6814 was very uninformative. I had two sensors on the Arducorder that I couldn't test, one being the gas sensor, and the other being the lightning sensor (monsoon season passed and there hasn't been lightning until just recently!). I took my best shot at deciphering the MiCS-6814 datasheet, recalculating the resistor values for 3.3V in place of 5V, and guessing on a heating protocol from other sensors. I'm still not convinced it's working properly though, as the resistance rarely ever changes. If I remember correctly, the datasheet suggested that the variance in resistance in a controlled environment could vary by /one to three orders of magnitude/, which appeared to only make it useful for measuring relative changes rather than absolute values (unless it was very well calibrated before hand), and even then it seemed uncertain what the accuracy would be. Gas sensors (and their associated heaters) are a bit messy as it is, and this one seems especially complicated and poorly documented -- I think someone writing a good set of documentation and example driving/reading circuits, with results under a few known gas concentrations, would go a long way to helping folks with this.
Are you sure? yes | no
hmm, I wonder if @peter jansen or @radu.motisan might have some of the answers?
Are you sure? yes | no