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
(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.