Power save MQ Sensors or alternatives

I've been testing some of this sensors, and all of them have the same "problem".Les talk about MQ2, reading the datasheet it say the heating consumption is less than 800 mW. Measuring the sensor, the consumption is around 114 mA, and the preheat time is over 24 hours!. So you can't use any kind of batteries, a 2000mA battery would last only 12 hours (without counting arduino consumption)

So I've to assume this kind of sensor have not designed to be handled with any kind battery. It could be better if the preheating time was less but I don't see any possibility to work with this sensors in a 24/7 project.
There is any alternative to this kind of sensors, with a lower consumption or lower preheating time?


The MQ sensors are the cheapest sensors that require the most current. Other sensors use less current.
The preheat time should be done just once. After the preheat is done, it takes about 2 minutes to 5 minutes to warm up the sensor to get a reasonable accurate value from the sensor.

These are other kind of sensors : http://www.winsen-sensor.com/products/4-series-electrochemical-toxic-gas-sensor/
I can't find what current they need.

Click on the tab "All Gas Sensors & Modules" : http://www.figarosensor.com/products/sensor/
There are a few of about 50mW or less.

There are many more. There are maybe 30 manufacturers of gas sensors.

Thanks Koepel,

I didn’t found too, even in the datasheet.

I coinued look the datasheet of the others MQ sensors, seems like every sensor has different heat time the MQ-7 says 60 seconds, the others hasn’t this information in the datasheet maybe I have to calculate this time by my selft It could be lower that I think.

Perhaps. I have tested the MQ-2 and a heating time of 2 minutes was good enough although after 5 minutes the output was stable.
The MQ-2 does get warm/hot because of the heater, so it takes some time until everything has settled. But if the environment is always the same (room)temperature and the 2 minutes is always exactly 2 minutes, then it has the same conditions every time and the output value can be used.

Professional test equipment can often not use a sensor with such a heater when working with combustable gasses. But the price jumps to hundreds of dollars, while some MQ gas sensors cost only 1 dollar on Ebay.

This one : http://us.msasafety.com/Portable-Gas-Detection/Multi-Gas/ALTAIR%26reg%3B-5X-Multigas-Detector/p/000080001600001023
can detect most gasses in a few seconds. It uses MSA XCell sensors and IR sensors. The MSA XCell sensors are those hatbox model sensors. Some cost 200 dollars, but I can not find the power requirements. I'm guessing that they still have a small heater inside, and the mechanical construction of the sensor makes it safe with combustable gasses.

My first question is how the most smoke and gas detectors can offer 2 years working with two AA batteries or 1 9v battery. I know one of the thing to get that consumption is to work with sleep times, but I'm trying to figure out, how to do it when a sensor has that time of heating time.

The thing is to get a good mix between the cost of the sensor and the consumption/heat time.

Meanwhile I keep googling others companies with better solutions and reasonable prices.

I am wondering that as well for some time. Buy one on Ebay and open it :wink:

Luckily for us, someone already did it. Reading I found the important info, they use a photoelectric smoke sensor, I assume this is only for smoke, I've to read more about gas detection, but now I've this page with some information:

And this with other information

I'll try a test with a common LDR to see if it works.