MQ-2 smoke sensors

I've been trying to incorporate the above smoke sensors into a design project but have come up against a problem with reading stability of the sensor.

When connected to a simple sketch I'm getting wild fluctuations in the sensor readings from 0 to 1023 & there doesn't seem to be a pattern.

I've checked 4 sensors & the results are much the same so I can't see 4 sensors ALL being defective.

i also tried other Arduino Uno's but got the same results

I read about 'burn in' of these sensors but even after 24 hours continuous running the readings still fluctuate wildly.

The adjustable trimmer doesn't seem to make any difference.

I tried connecting Aout to GND with a 2K resistor but no change

Anyone had experience of these sensors?


The sensors are marked ICSG017A ( 4 pin (Vcc, Aout, Dout, GND) I don't use the DOUT pin


Robert Wall's picture

Re: MQ-2 smoke sensors

Is your power supply sufficient? The sensor spec. sheet says power consumption is not greater than 800 mW.

Can you look at the output with an oscilloscope or even a multimeter to see what you're actually getting?

dominator99's picture

Re: MQ-2 smoke sensors

Found the problem; a 'dodgy' GND cable connection to Uno board.

Just missed your reply Robert; my psu is 5.16V (measured on multimeter) rated at 2A so well in excess of 800mA of sensor but thanks for the feed back

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