Gas Sensors

Initial report by Jen 10/22/05
Gas sensors detect levels of various gases in the air.

The sensors I studied are pictured below. Model TGS 2442 (white) is pictured on the left and models TGS 2600, 2602, and 2620 are on the right (silver).


Picture from Figaro Engineering Inc.

Applications

Odor-Based Incontinence Sensor

Autonomous Feral Robotic Dogs

Electrical Characteristics

This report will cover four different models of gas sensors made by Figaro Engineering Inc.
Although there is some overlap, each sensor detects a slightly different set of gases. Listed below are the sensor model numbers and the list of gases they detect in order of priority according to their data sheets.

TGS 2442 Data Sheet - Carbon Monoxide (CO)
TGS 2600 Data Sheet - Hydrogen (H), Ethanol (C2H6O), Iso-butane (CH3CH(CH3)2), Carbon Monoxide (CO), Methane (CH4)
TGS 2602 Data Sheet - Toluene (C7H8), Hydrogen Sulfide (H2S), Ethanol (C2H6O), Ammonia (NH3), Hydrogen (H)
TGS 2620 Data Sheet - Ethanol (C2H6O), Hydrogen (H), Iso-butane (CH3CH(CH3)2), Carbon Monoxide (CO), Methane (CH4)

Put a link to the datasheet at the top. Also link any retail sources, for example if you're using a breakout board, or any other parts that making the sensor easier.

Give the voltage and amperage ranges, and any other relevant electrical data.

Describe the electrical changes when the sensor senses whatever physical changes it senses.

Pin Descriptions

Give a list of the pins, and a pin diagram as appropriate. Detail the function of each pin in a short paragraph following the list.

Microcontroller Connections

Explain how to connect the sensor to a microcontroller or computer. Include a schematic and any other necessary diagrams. Make sure to include a list of every part in the schematic.

Code Sample

Give a code sample for the microcontroller you developed the example on. Link it to the Code group of the wiki, formatting the link like this:

Code Sample

Typical Behavior

Describe the behavior of the sensor when you use it to sense something. Note any peculiarities that you had to work around, or things that might affect someone else's use. Graphs and images are useful here.

Application Notes

Describe your own application of the sensor. Link to any external documentation of your project, and discuss how you got the sensor to do what you needed it to.