Hello everyone,
I'm making a project with two Arduino Yùn which acquire Methane through MQ-4 gas sensors.
I've built 3 couple of circuits to let them work correctly (using resistance of 20 Kohms) but in each of the three tests one sensor gave 900 parts for million, instead the other almost 300. Obviously they were in the same room, very close to each other and not in direct presence of warm or heat sources.
The scheme of the connections is:
Sensor PINS:
A E
B F
C G
E,F,G to 5 Volts D.C.
A to A0 (Analog0 pin)
B to GND (Ground pin)
C to 20Kohm resistance then connected to the GND pin
What could be the reason for this difference?
