Hello guys i hope you fine, i am trying to use the MICS6814 Pollution sensor to get CO data, the thing is how to measure these params... first of all, it works at 5 V, mi MCU works at 3.3 v, the value what i get from the ADC (let's say it is 1200) is this the RS? i understand that you have to measure R0 also (whichi is measurement in controlled conditions) and then RS in a normal enviroment but, what supposed have i do with these two data? Divide RS/R0? i see the following graph in the datasheet:
The heater works at 5V (in the example circuit), the sensor just has a varying resistance. If you use the second circuit in the datasheet to read the value you already adapted to the MCU Vcc (given that you don't think that Vcc is 5V).
And no the value you get is the resulting voltage but you can calculate RS from that.
HI man, yeah i have the second circuit in the datasheet runing, where VCC is 3.3 V in my case, but sensor is powered by 5V (because of the heater as well you said), so the outcome fomr ADC is voltage, right?¿ i thought i need to do: Voltage = 1024/ADC_VAL,...is this the voltage?¿ once i get this, i can get RS right?
RS from the scheme i understand is the sensor itself...in this case CO pin
And what IO pins did you use? What sketch are you using (don't forget the code tags when posting!)?
If you use the whole chain of resistors without connecting any IO pins you get the following calculation:
VAD = VCC - VCC / (RS + 1106000) * 1106000
where
VAD = VCC / AD_MAX * AD_VALUE
If you read a value of 1200 AD_MAX cannot be 1024 as that would mean you read a value greater than the maximum value.
As you didn't tell us what MCU you're using you have to find out what maximum value your AD has.
My ADC uses 12 bits ADC whic ic 4096, but in RS = AD_VALUE * 1106000 / (AD_MAX - AD_VALUE) i don't need to use this data right? i just want to get RS, so let's say for example i read 900 from ADC,
RS = 900 * 1106000 / (4095 - 900) ir this right?