I have an MQ-4 sensor connected to a Beetle Bluno BLE that seems to work fine, however, when I change the board to an Arduino Nano 33 BLE, the sensor doesn't seem to work well (I get an arbitrary oscillation in values coming from the sensor but these don't increase or decrease with the presence of gas).

Beetle Bluno BLE setup:

  • MQ-4:GND -> Beetle:GND
  • MQ-4:VCC -> Beetle:5v
  • MQ-4:AO -> Beetle:A1

Arduino Nano 33 BLE setup:

  • MQ-4:GND -> Arduino:GND
  • MQ-4:VCC -> Arduino:3.3v
  • MQ-4:AO -> Arduino:A1

enter image description here (image slightly missleading because VCD is actually not connected to 5V but to 3.3V)

The only difference is the 5v instead of 3.3v, however, I also tried powering the sensor externally with 5v and it makes no difference.

  • A schematic might be helpful, particularly for the Arduino, along with "not working well" actually means. Commented Jul 1, 2021 at 22:05
  • Description updated with a schematic and a definition
    – human
    Commented Jul 1, 2021 at 22:25
  • You fixed the 5V jumper and verified it's putting out 5V? Commented Jul 1, 2021 at 22:26
  • No, I am not using the 5v but the 3.3v pin instead
    – human
    Commented Jul 1, 2021 at 22:29
  • AFAIK that sensor requires 5V according to sources like the SparkFun. Commented Jul 1, 2021 at 22:31


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