MQ2 - floating Voltage output on PCB

Projects General Guidance
1

Hi,

I'm trying to make a sensor to my 3D printer chamber.

After testing on breadboard my MQ2 sensor works fine. I've used a voltage divider and my output from MQ2 are quite low (260-360 - depends on the burning time), but after detecting some smoke it's growing to some values (like 900, 1200, even 2k). But when i moved it to PCB and connecting everything the same as on the breadboard - voltage from A0 are floating like crazy. It's from 600 to 800 and even 1200 mV. (i measured the voltage between A0 and GND)

I'm using ESP32 Wroom32. I've got two separate modules one on the breadboard and one on the PCB. After switching MQ2 sensor or microcontroller between PCB and breadboard, output from PCB always floating. Dunno why. I've got connection to GND on the ESP32.

I also checked voltage regulator, all GND, VIN, VOUT. There is no short circuit at all.

Here is some pics: MQ2 Sensor Connection - Album on Imgur

Could someone help me? I'm probably doing something wrong but i cannot find what.

2

Sounds like an open circuit somewhere. Check for continuity on all wiring and PCB traces.

3

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