Broad coverege gas senor.

Hello.

I must say i am as new as they come to arduino. I have bought some of them for my 3d printer and cnc mill projects. But these basicly have theyr code and pinouts laid out for you. Nothing much to learn.

Well i was scrolling trough ebay for once, and found these gas sensors. Mq2-4 etc And i thought that could be a good utility to use with my multirotor. Sometimes it would be better to send in a uav to sense for hazardous materials.

My question then, wich sensors would i choose to get as broad a coverage as possible for gases and other materials. And is it even possible to hook say 3 or more sensors to one arduino?

i recomend MQ-2. i use one, it can detect LPG, propane, hydrogen and smoke (maybe more types). i use the brick version (img atached) so i’m spared of complicated circuits xD.
I can tell you this: it consumes 120mAh, so you might consider using an alternate 5V power supply for them. You can connect up to 6 (on an arduino uno).
It takes around 20 seconds to heat up and then it will be ready to sense properly. (first use takes around 2-3 minutes to heat up and show consistent data)
Goodluck!

check power of the sensors.

each sensor can detect something slightly different than the next.

if your specific gas is listed, then you are in a good place to start.

check the manufactures site for data sheet to get power these types of gas sensors use a heater so draw a lot of power.

Figaro is one manufacture Henan Hanwei Electronics is another

another sensor, not sure of the manufacturer offers for different types. http://www.winsentech.com/pmbdt/WSP2110_VOC_Gas_Sensor_27.html

thinking about air flow.
the flow of air around an quad-copter would be downward.
the air above would be what the sensor sees.

not sure of the application, but it would be worth looking into.
I would offer that you would be well served to contact the manufactures of the sensors and see what MEMS options they have. the Air Wick sensor is tiny and battery powered.

http://eu2015.memscongress.com/tech-showcase/

these are all heated sensors. metal oxide.
they are all very broad based and only detect certain elements. a carbon sensor will detect alcohol as it breaks down and releases carbon. so do all acids… you cannot easily determine an exact composition.

there is another type, chemical sensors. the chemicals are used in an enclosed evaporation chamber and the chemicals deplete over time of use. but chem sesnsors are what are used in battery devices. this is older technology, but I think offers very exact sensing of specif things.

Thank you Dave.

Yes the downwash has crossed my mind, but even so. it would be a good project for a rover uav in worst case. The plan was to go inn into uncharted locations to search for prescense of hazardous materials. therefore as wide a spektrum of possible substances as possible.

There would not ba an abundance of missions where this sensor package would be needed. But with the prices as low as they are now i dont see a reason i should not have a good array of sensor systems available.