I am planning to monitor the air quality by measuring the concentration of CO, LPG and Methane gases with MQ sensors that are linked below.
I came across the tutorial posted on Arduino website linked below.
Arduino Playground - MQGasSensors. Some parts on the tutorial are not clear, they are listed below.
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“The heater may not be connected directly to an output-pin of the Arduino, since it uses too much current for that.”
Does it mean that I should not connect it to any of the digital pins ? Can I connect it to the 5 volts from the Arduino board ? or should I use external power supply for this. -
“A time of 12 or 24 hours is usually used for the burn-in time.”
Do I need to supply 5 volts to the sensors for 12 hours? -
“In some special cases a specific burn-in is needed. See the datasheet if the sensor needs such a specific burn-in.”
Do I need the specific burn in for MQ7, MQ6 and MQ4. -
Do I need a special library for the sensor, or can I only use the analogRead