Hi! I'm trying to configure the MQ-5 module so as to meassure GLP gas. The values I measured in PPM are about 0,002 when no gas is in free air. By defalut, RL is 1 kohm but test in datasheet uses RL= 20 kohm. Maybe I have to change RL but I'm not sure... I also calibrated by heating up for 24 hours as the datasheet recommends.
Hi, it seems that no one has answered yet. It is a strange question.
The MQ-5 sensor is not very accurate and it is not possible to determine which gas it senses.
There are sketches that try to calculate the PPM with a certain curve. But that is just to play with, it is not a serious number.
The datasheet shows RL = 20kΩ, then you should start with 20kΩ. After that you can adjust the sketch.
After the 24 hours, you still have to heat up the sensor before taking a measurement. That might take a few minutes.
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