|
Size Power (mA) Indep. heater power Enable control Digital output Pre-heat (seconds) Burn-in time (hours) Board Cost (USD) |
Adafruit MiCS-5524 13x20 mm 32 No Yes No ~60 24 14.95 |
MQ-3 Module 20x32 mm 129 No No Yes ~170 24 6.99 |
The pre-heat time was measured from graphs from sensor power on to when the first reading was within +/- 5% of the steady state value. The MiCS-5524 undershoots initially and then quickly recovers ahead of the MQ-3.
The lower power of the Adafruit MiCS-5524 makes it easier to use and less taxing on power supply/batteries. The enable feature could also be useful for power saving if continuous measurement is not required.
The MiCS-5524 is roughly twice as sensitive in terms of Ro/Rs compared to the MQ-3 for alcohol and gasoline (petrol) but care needs to be taken with very high ppm samples as output will fluctuate.
The SGX MiCS FAQ and SGX General FAQs have entries on airflow:
Yes. Direct airflow on the sensor surface will change the conductivity of the sensor by altering the heated layer temperature. That is why SGX Sensortech recommends placing the sensor behind a Teflon membrane in most applications. The Teflon membrane allows diffusion of the gases, while reducing the influence of the air speed.
