Reports.GasSensors History

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!!!Gas Sensors
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Figaro Engineering Inc. makes a nice selection of gas sensors that detect a variety of common atmospheric gases and contaminants.
[[http://www.figaro.co.jp/en/top.html | ThisWiki:/uploads/Reports/sensor2.jpg]]
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I purchased my sensors from [[http://www.figarosensor.com/ | Figaro Engineering Inc.]]\\
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[--Picture from [[http://http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]--]\\
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I purchased my sensors from [[http://www.figarosensor.com/ | Figaro Engineering Inc.]]\\
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[--Picture from [[http://http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]--]\\
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The wiring for these sensors is incredibly simple. The value across R'_L_', the load resistor, is simply sent to one of the analog inputs on the pic. Typically this would be used to trigger an alarm in cases of danger. There are several more complicated circuits listed in the data sheets, designed to account for extreme temperatures which could be necessary in some work environments, but the basic wiring for this sensor is very direct.
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To counteract this, it is a good idea to build a pause into you program by either delaying its start or by telling the microcontroller to ignore any hits above the action level for the first minute or so.
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Some stuff I noticed:
* These sensors react very quickly to high concentrations of volatile organic chemicals in the air, but do not seem to take at least twice, or three times as long to return to 'normal'.
* They get very HOT. I called the company to find out exactly how hot and was told that the heating element can get up to 350 degrees Celcius and the housing heats up to around 50 degrees Celcius. To mitigate this problem, I used heat sinks. This seemed to keep the overall circuit from heating up too much, but the sensor itself seems to get hot regardless.
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!!!Application Notes
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!!!Application Notes
Some stuff I noticed:
* These sensors react very quickly to high concentrations of volatile organic chemicals in the air, but do not seem to take at least twice, or three times as long to return to 'normal'.
* They get very HOT. I called the company to find out exactly how hot and was told that the heating element can get up to 350 degrees Celcius and the housing heats up to around 50 degrees Celcius. To mitigate this problem, I used heat sinks. This seemed to keep the overall circuit from heating up too much, but the sensor itself seems to get hot regardless.
* The sensors need time to heat up on startup. The data sheets say to pause sampling for several seconds, but in playing with these sensors, I am finding that they require a minute or more to heat up and stabilize to the ambient air conditions. Below is a graph of the behavior of these sensors on being powered up.
[[Attach:startup.gif]]
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This simple [[Code.leds | PicBasic Pro code]] will light three LEDs when the level of air contaminants reaches a point when the serial out of the sensor exceeds 400, (about halfway through the sensor's range) in addition to giving three serial out values for three of these sensors.
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Below are some graphs showing the behavior of each of these sensors in the presence of a large quanitity of various chemicals. Notice that each of the sensors responds differently to each chemical. It is also important to note that these sensors can detect WHETHER an environmental contaminant is present and approximately HOW MUCH in ppm. They CAN NOT identify the contaminant. The sensors that I am using here have not been calibrated or properly pre-heated and are therefore not giving accurate ppm readings.
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||'''Recommended Pre-heating duration'''|| || || || ||
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||'''Recommended Pre-heating duration'''||2-7 days ||2-7 days ||2-7 days ||2 days ||
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#Sensor Electrode (output) - must be connected to load resistor (R'_L_') and ground, the value of this pin can be sent to an analog-in on a microprocessor
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#Sensor Electrode (output) - must be connected to load resistor (R'_L_') and ground, the value of this pin can be sent to an analog-in on a microprocessor, R'_L_' should be between 500 and 2K ohms, but the appropriate value for R'_L_' will change with use (without 7 days pre-heating), to compensate use a variable resistor
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* They get very HOT.
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* They get very HOT. I called the company to find out exactly how hot and was told that the heating element can get up to 350 degrees Celcius and the housing heats up to around 50 degrees Celcius. To mitigate this problem, I used heat sinks. This seemed to keep the overall circuit from heating up too much, but the sensor itself seems to get hot regardless.
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* They get very HOT.
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* They get very HOT.


!!!Application Notes
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I used a .56k ohm resistor for the load resistor on TGS 2620 and 2602, and 2600. This yeilded a 600-700 point range on each of these sensors when exposed to a very high concentration of ethanol. Each sensor differed slightly in its range. The use of a sensitve trimmer pot to calibrate the sensor before each use might solve this problem.
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I used a .56k ohm resistor for the load resistor on TGS 2620 and 2602, and 2600. This yeilded a 600-700 point range on each of these sensors when exposed to a very high concentration of ethanol. Each sensor differed slightly in its range. The use of a sensitve trimmer pot to calibrate the sensor before each use might solve this problem.

!!!Microcontroller Connections
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||'''Load Resistance'''||.5k ~ 1.5k ohms||.5k ~ 1.5k ohms ||.5k ~ 1.5k ohms|| ||
||'''Recommended Pre-heating duration'''|| || || || ||

I used a .56k ohm resistor for the load resistor on TGS 2620 and 2602, and 2600. This yeilded a 600-700 point range on each of these sensors when exposed to a very high concentration of ethanol. Each sensor differed slightly in its range. The use of a sensitve trimmer pot to calibrate the sensor before each use might solve this problem.
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Here's a modified version of Tom's [[http://itp.nyu.edu/physcomp/sensors/Code/DataloggerMulti | Processing Datalogger Multi]] code that allows you to look at the [[Code.multi | output of three sensors at the same time.]]
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Here's a modified version of Tom's [[http://itp.nyu.edu/physcomp/sensors/Code/DataloggerMulti | Processing Datalogger Multi]] code that allows you to look at the [[Code.multi | output of three sensors at the same time.]]

!!!Typical Behavior
Some stuff I noticed:
* These sensors react very quickly to high concentrations of volatile organic chemicals in the air, but do not seem to take at least twice, or three times as long to return to 'normal'.
* They get very HOT.
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#Sensor Electrode (output) - must be connected to load resistor and ground. the value of this pin can be sent to an analog in on a microprocessor
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#Sensor Electrode (output) - must be connected to load resistor (R'_L_') and ground, the value of this pin can be sent to an analog-in on a microprocessor
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#Heater Ground
#Sensor Electrode (output)
#Sensor Electrode (input)
#Heater Power (+5V)
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#Heater Ground - Ground (0V)
#Sensor Electrode (output) - must be connected to load resistor and ground. the value of this pin can be sent to an analog in on a microprocessor
#Sensor Electrode (input) - (+5V)
#Heater Power -
(+5V)
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'''Pin Connections'''
#Heater Ground
#Sensor Electrode (output)
#Sensor Electrode (input)
#Heater Power (+5V)
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!!!Pins

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!!!Pin Descriptons

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!!!Code Sample
Here's a modified version of Tom's [[http://itp.nyu.edu/physcomp/sensors/Code/DataloggerMulti | Processing Datalogger Multi]] code that allows you to look at the [[Code.multi | output of three sensors at the same time.]]
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In the picture below I used a potentiometer to alter the resistance of the load resistor. Another option would be to use a trimmer pot.
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In the picture below I used a potentiometer to alter the resistance of the load resistor. Another option would be to use a trimmer pot or a fixed resistor.
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I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]].
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I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]].\\
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I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]]. They also provide [[http://www.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
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I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]].
They also provide [[http://www.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases. Gas sensors detect amounts of certain gases in parts per million or ppm, which is a unit of concentration, in the immediate surrounding area.\\
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases. Gas sensors detect amounts of certain gases in parts per million or ppm, which is a unit of concentration, in the immediate surrounding area.

You can calculate percent from ppm by dividing the ppm by 1,000,000 and multiplying by 100. So if you can detect 300ppm of ethanol in the air, the air is 3% ethanol, and you might be at TNO.\\
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You can calculate percent from ppm by dividing the ppm by 1,000,000 and multiplying by 100. So if you can detect 300ppm of ethanol in the air, the air is 3% ethanol, and you might be at TNO.\\
\\
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases. Gas sensors detect amounts of certain gases in parts per million or ppm, which is a unit of concentration, in the immediate surrounding area.
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases. Gas sensors detect amounts of certain gases in parts per million or ppm, which is a unit of concentration, in the immediate surrounding area.\\
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You can calculate percent from ppm by dividing the ppm by 1,000,000 and multiplying by 100. So if you can detect 300ppm of ethanol in the air, the air is 3% ethanol, and you might be at TNO.
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You can calculate percent from ppm by dividing the ppm by 1,000,000 and multiplying by 100. So if you can detect 300ppm of ethanol in the air, the air is 3% ethanol, and you might be at TNO.\\
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There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.
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There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each. \\
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\\
There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.
\\
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There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.
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*Natalie Jeremijenko used them in her [[http://xdesign.ucsd.edu/feralrobots/ | Feral Robotic Dogs]] project in which she retro-fitted store bought toy dogs with these sensors and modified them to sniff out enviromental toxins.\\
*Huadong
Wu and Mel Siegel at Carnegie Mellon's Robotics Institute developed an [[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]] using these sensors. I don't really think I need to say anymore about that.\\
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*Natalie Jeremijenko used them in her [[http://xdesign.ucsd.edu/feralrobots/ | Feral Robotic Dogs]] project in which she retro-fitted store bought toy dogs with these sensors and modified them to sniff out enviromental toxins.
*Huadong
Wu and Mel Siegel at Carnegie Mellon's Robotics Institute developed an [[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]] using these sensors. I don't really think I need to say anymore about that.
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I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]] if you are planning on using these sensors. I found it very helpful. They also provide [[http://www.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
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I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]]. They also provide [[http://www.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
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\\
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases, some of which are better for us than others. Some gases are ok in small quantities, but not so good in larger quantities. Some are inert and some are flammable. Gas sensors detect amounts of certain gases in parts per million (a unit of concentration) in the immediate surrounding area. I found a pretty good explanation for parts per million (ppm) which I cut and pasted from
[[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Ppm.html | Kimball's Biology Pages:]]\\
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases. Gas sensors detect amounts of certain gases in parts per million or ppm, which is a unit of concentration, in the immediate surrounding area.
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'''Parts Per Million (PPM)'''\\
A unit of concentration often used when measuring levels of pollutants in air, water, body fluids, etc. One ppm is 1 part in 1,000,000. The common unit mg/liter is equal to ppm. Four drops of ink in a 55-gallon barrel of water would produce an "ink concentration" of 1 ppm. \\
\\
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The Occupational Safety and Health Administration, [[http://www.osha.gov/ | OSHA]], has laws about acceptable amounts of gaseous chemicals that workers can be exposed to. These 'acceptable levels' are called Permissible Exposure Limits or [[http://www.cdc.gov/niosh/pel88/npelname.html | PELs]]. Companies are legally obliged to make sure their workers' exposure to a given chemical does not exceed that chemical's [[http://www.cdc.gov/niosh/pel88/npelname.html | PEL]]. These sensors can be used to control ventilation systems, turn on air cleaners, or to trigger alarms if gaseous chemicals reach dangerous levels. The list of industries and settings where these sensors are used to maintain worker safety is very long and includes chemical plants, pharmaceutical production, fertilizer plants, automotive garages, biomedical and chemical research labs, healthcare facilities, dry cleaners, industrial kitchens, and many more.\\
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*Mainataining worker safety in industrial, biomedical, healthcare and other industries
*Controlling ventilation (HVAC) systems
*Triggering air filters and cleaners
*Natalie Jeremijenko used them in her [[http://xdesign.ucsd.edu/feralrobots/ | Feral Robotic Dogs]] project in which she retro-fitted store bought toy dogs with these sensors and modified them to sniff out enviromental toxins.\\
*Huadong Wu and Mel Siegel at Carnegie Mellon
's Robotics Institute developed an [[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]] using these sensors. I don't really think I need to say anymore about that.\\
*I plan
to use these sensors in a project for the [[http://www.jennyjeanne.com/classes/wearables/?p=6 | Wearable Technology]] class. I hope to create an accessory that responds to air quality by changing shape.

!!!Electrical Characteristics
This report will cover four different models of gas sensors made by [[http://www.figaro.co.jp/en/top.html | 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 some of the gases they detect in order of priority according to their data sheets. \\
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In addition to worker safety, I found some more creative applications for these sensors.\\
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TGS 2442 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2600 [[http://www.figarosensor.com/products/2600pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
TGS 2602 [[http://www.figarosensor.com/products/2602pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Toluene| Toluene]] (C'_7_'H'_8_'), [[http://en.wikipedia.org/wiki/Hydrogen Sulfide| Hydrogen Sulfide]] (H'_2_'S), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Ammonia | Ammonia]] (NH'_3_'), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2620 [[http://www.figarosensor.com/products/2620pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')
\\
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Natalie Jeremijenko used them in her [[http://xdesign.ucsd.edu/feralrobots/ | Feral Robotic Dogs]] project in which she retro-fitted store bought toy dogs with these sensors and modified them to sniff out enviromental toxins.\\
\\
Huadong Wu and Mel Siegel at Carnegie Mellon's Robotics Institute developed an [[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]] using these sensors. I don't really think I need to say anymore about that.\\
\\
I plan to use these sensors in a project for the [[http://www.jennyjeanne.com/classes/wearables/?p=6 | Wearable Technology]] class. I hope to create an accessory that responds to air quality by changing shape.

!!!Electrical Characteristics
This report will cover four different models of gas sensors made by [[http://www.figaro.co.jp/en/top.html | 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 some of the gases they detect in order of priority according to their data sheets. \\
\\
TGS 2442 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2600 [[http://www.figarosensor.com/products/2600pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
TGS 2602 [[http://www.figarosensor.com/products/2602pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Toluene| Toluene]] (C'_7_'H'_8_'), [[http://en.wikipedia.org/wiki/Hydrogen Sulfide| Hydrogen Sulfide]] (H'_2_'S), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Ammonia | Ammonia]] (NH'_3_'), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2620 [[http://www.figarosensor.com/products/2620pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
\\
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I purchased my sensors from [[http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]\\
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I purchased my sensors from [[http://www.figarosensor.com/ | Figaro Engineering Inc.]]\\
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!!!Pins

[[Attach:pins.jpg]]
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The sensing element is coated with a metal oxide, usually SnO'_2_' (tin oxide), which is oxidized when it is heated. From here, my comprehension of the chemistry is tenuous at best, but as I understand it, the SnO'_2_' donates electrons from itself to the O'_2_', resulting in negatively charged O'_2_' molecules and positively charged SnO'_2_' left on the surface of the sensor. The positivly charged SnO'_2_' acts as a barrier to electron flow and increases the resistance of the sensor. In the presence of a deoxidizing gas, such as ethanol fumes, the ratio of available oxygen decreases, so there is less oxygen to accept the SnO'_2_''s donor electrons, which means that the SnO'_2_' is not as positively charged and the resistance of the sensor is reduced. Gas levels are determined by measuring the voltage across a load resistor which is put between the negative pin of the sensing element and ground. The load resistor can varry between models, between sensors, and depending on conditions in which the sensor is being used.
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The sensing element is coated with a metal oxide, usually SnO'_2_' (tin oxide), which is oxidized when it is heated. From here, my comprehension of the chemistry is tenuous at best, but as I understand it, the SnO'_2_' donates electrons from itself to the O'_2_', resulting in negatively charged O'_2_' molecules and positively charged SnO'_2_' left on the surface of the sensor. The positivly charged SnO'_2_' acts as a barrier to electron flow and increases the resistance of the sensor. In the presence of a deoxidizing gas, such as ethanol fumes, the ratio of available oxygen decreases, so there is less oxygen to accept the SnO'_2_''s donor electrons, which means that the SnO'_2_' is not as positively charged and the resistance of the sensor is reduced. Gas levels are determined by measuring the voltage across a load resistor which is put between the negative pin of the sensing element and ground. This change in resistance can be sent as an analog value to a microprocessor. The load resistor can varry between models, between sensors, and depending on conditions in which the sensor is being used.
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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.myCodeSample | 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.
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These sensors use a wheatstone bridge to detect gases.
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These sensors use a [[http://itp.nyu.edu/physcomp/sensors/Schematics/WheatstoneBridge |wheatstone bridge]] to detect gases. Two of the four pins on the sensor are connected to a heater and the other two are connected to the sensing element as shown in the diagram below.\\

[[Attach:fig1.jpg]]

The sensing element is coated with a metal oxide, usually SnO'_2_' (tin oxide), which is oxidized when it is heated. From here, my comprehension of the chemistry is tenuous at best, but as I understand it, the SnO'_2_' donates electrons from itself to the O'_2_', resulting in negatively charged O'_2_' molecules and positively charged SnO'_2_' left on the surface of the sensor. The positivly charged SnO'_2_' acts as a barrier to electron flow and increases the resistance of the sensor. In the presence of a deoxidizing gas, such as ethanol fumes, the ratio of available oxygen decreases, so there is less oxygen to accept the SnO'_2_''s donor electrons, which means that the SnO'_2_' is not as positively charged and the resistance of the sensor is reduced. Gas levels are determined by measuring the voltage across a load resistor which is put between the negative pin of the sensing element and ground. The load resistor can varry between models, between sensors, and depending on conditions in which the sensor is being used.

In the picture below I used a potentiometer to alter the resistance of the load resistor. Another option would be to use a trimmer pot.

ThisWiki:/uploads/Reports/cd4.jpg\\
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There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.
to:
There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.

These sensors use a wheatstone bridge to detect gases.
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||'''! Electrical Requirements and Characteristics !'''||
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||! ''' Electrical Requirements and Characteristics ''' !||
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Give the voltage and amperage ranges, and any other relevant electrical data.
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||! Electrical Requirements and Characteristics !||
|| ||'''TGS 2600'''||'''TGS 2602'''||'''TGS 2620'''||'''TGS 2442'''||
to:
||'''! Electrical Requirements and Characteristics !'''||
|| || '''TGS 2600''' || '''TGS 2602''' || '''TGS 2620''' || '''TGS 2442''' ||
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|| || '''TGS 2600''' || '''TGS 2602''' || '''TGS 2620''' ||'''TGS 2442''' ||
|| '''Voltage''' || 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
|| '''Current'''
|| 42mA || 56mA || 42mA || 203mA ||
|| '''Sensor Resistance'''
||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
to:
|| ||'''TGS 2600'''||'''TGS 2602'''||'''TGS 2620'''||'''TGS 2442'''||
||'''Voltage'''|| 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
||'''Current'''|| 42mA || 56mA || 42mA || 203mA ||
||'''Sensor Resistance'''||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
Changed lines 51-55 from:
|| || !TGS 2600 || !TGS 2602 || !TGS 2620 || !TGS 2442 ||
|| !Voltage || 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
|| !Current || 42mA || 56mA || 42mA || 203mA ||
|| !Sensor Resistance
||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
to:
|| || '''TGS 2600''' || '''TGS 2602''' || '''TGS 2620''' ||'''TGS 2442''' ||
|| '''Voltage'''
|| 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
|| '''Current'''
|| 42mA || 56mA || 42mA || 203mA ||
|| '''Sensor Resistance'''
||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
Changed lines 51-55 from:
|| || ! TGS 2600 || ! TGS 2602 || ! TGS 2620 || ! TGS 2442 ||
|| Voltage || 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
|| Current || 42mA || 56mA || 42mA || 203mA ||
|| Sensor Resistance ||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
to:
|| || !TGS 2600 || !TGS 2602 || !TGS 2620 || !TGS 2442 ||
|| !Voltage || 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
|| !Current || 42mA || 56mA || 42mA || 203mA ||
|| !Sensor Resistance ||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
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|| border=1
||! Electrical Requirements and Characteristics !||
|| || ! TGS 2600 || ! TGS 2602 || ! TGS 2620 || ! TGS 2442 ||
|| Voltage || 5.0V DC || 5.0V DC || 5.0V DC || 5.0V DC ||
|| Current || 42mA || 56mA || 42mA || 203mA ||
|| Sensor Resistance ||10k ~ 90k ohms||10k ~ 10k ohms ||1k ~ 5k ohms||6.81k ~ 68.1 k ohms ||
Changed lines 49-79 from:
<table width="583" height="248" border="0">
<tr>
<td width="101">&nbsp;</td>
<td width="105"><strong>TGS 2600</strong></td>
<td width="110"><strong>TGS 2602 </strong></td>
<td width="103"><strong>TGS 2620</strong></td>
<td width="142"><strong>TGS 2442 </strong></td>
</tr>
<tr>
<td><strong>Voltage</strong></td>
<td>5.0V DC </td>
<td>5.0V DC </td>
<td>5.0V DC </td>
<td>5.0V DC </td>
</tr>
<tr>
<td><strong>Current</strong></td>
<td>42 mA </td>
<td>56 mA</td>
<td>42mA</td>
<td>203mA</td>
</tr>
<tr>
<td><strong>Sensor Resistance</strong></td>
<td>10k ~ 90k ohms </td>
<td>10k ~ 10k ohms </td>
<td>1k ~ 5k ohms </td>
<td> 6.81k ~ 68.1 k ohms </td>
</tr>
</table>
to:
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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.
to:
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<table width="583" height="248" border="0">
<tr>
<td width="101">&nbsp;</td>
<td width="105"><strong>TGS 2600</strong></td>
<td width="110"><strong>TGS 2602 </strong></td>
<td width="103"><strong>TGS 2620</strong></td>
<td width="142"><strong>TGS 2442 </strong></td>
</tr>
<tr>
<td><strong>Voltage</strong></td>
<td>5.0V DC </td>
<td>5.0V DC </td>
<td>5.0V DC </td>
<td>5.0V DC </td>
</tr>
<tr>
<td><strong>Current</strong></td>
<td>42 mA </td>
<td>56 mA</td>
<td>42mA</td>
<td>203mA</td>
</tr>
<tr>
<td><strong>Sensor Resistance</strong></td>
<td>10k ~ 90k ohms </td>
<td>10k ~ 10k ohms </td>
<td>1k ~ 5k ohms </td>
<td> 6.81k ~ 68.1 k ohms </td>
</tr>
</table>
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TGS 2600, 2602, and 2620 operate on 5.0V(+ or - 0.2V)DC/AC.
TGS 2442 operates on a heater voltage cycle of 4.8V(+ or - 0.2V)DC to 0V and a circuit voltage of 0V to 5.0V(+ or - 0.2V)DC.

TGS 2600 and 2620
TGS 2602
TGS 2442
to:
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There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tac on a sur-charge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.
to:
There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tack on a surcharge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.
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The MMA7260Q operates on 2.2-3.6VDC, and uses very little current (500uA). It has three analog outputs, one for each axis. Acceleration on each axis generates a voltage from 0 to approximately 3.3V.
to:
TGS 2600, 2602, and 2620 operate on 5.0V(+ or - 0.2V)DC/AC.
TGS 2442 operates on a heater voltage cycle of 4.8V(+ or - 0.2V)DC to 0V and a circuit voltage of 0V to 5.0V(+ or -
0.2V)DC.

TGS 2600 and 2620
TGS 2602
TGS 2442
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to:
There is no way to order online from Figaro. You have to write to the company, ask for a pricelist, and then email them to order. They require payment in advance for delivering to a residence, and tac on a sur-charge for orders under $50. The sensors that are being discussed here are the cheapest and run about 15$ each.

The MMA7260Q operates on 2.2-3.6VDC, and uses very little current (500uA). It has three analog outputs, one for each axis. Acceleration on each axis generates a voltage from 0 to approximately 3.3V.
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I had to write to the company to get extended data sheets for TGS 2600 and TGS 2602. I put links to the pdf files here:
[[Reports.TGS 2600 | TGS 2600]]
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I had to write to the company to get extended data sheets for TGS 2600 and TGS 2602. I put links to the pdf files here: \\
[[Reports.TGS 2600 | TGS 2600]] \\
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There are also links for an extended data sheet for [[http://www.figarosensor.com/products/2620Dtl.pdf | TGS 2620]], an extended data sheet for [[http://www.figarosensor.com/products/2442Dtl.pdf | TGS 2442]], and [[http://www.figarosensor.com/products/signal.pdf | signal processingand calibration notes for TGS 2442]].
to:
There are also links for an extended data sheet for [[http://www.figarosensor.com/products/2620Dtl.pdf | TGS 2620]], an extended data sheet for [[http://www.figarosensor.com/products/2442Dtl.pdf | TGS 2442]], and [[http://www.figarosensor.com/products/signal.pdf | signal processing and calibration notes for TGS 2442]].
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[[Reports.TGS 2600 | TGS 2600]] -[[Jen]]
[[
Reports.TGS 2602 | TGS 2602]] -[[Jen]]
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[[Reports.TGS 2600 | TGS 2600]]
[[Reports.TGS 2602 | TGS 2602]]
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There are also links for an extended data sheet for [[http://www.figarosensor.com/products/2620Dtl.pdf | TGS 2620]], an extended data sheet for [[http://www.figarosensor.com/products/2442Dtl.pdf | TGS 2442]], and [[http://www.figarosensor.com/products/signal.pdf | signal processing]] and calibration notes for TGS 2442.
In addition, Figaro also provides useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information]] documentation and [[http://www
.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
to:
There are also links for an extended data sheet for [[http://www.figarosensor.com/products/2620Dtl.pdf | TGS 2620]], an extended data sheet for [[http://www.figarosensor.com/products/2442Dtl.pdf | TGS 2442]], and [[http://www.figarosensor.com/products/signal.pdf | signal processingand calibration notes for TGS 2442]].

I had to write to the company to get extended data sheets for TGS 2600 and TGS 2602
. I put links to the pdf files here:
[[Reports.TGS 2600 | TGS 2600]] -[[Jen]]
[[Reports.TGS 2602 | TGS 2602]] -[[Jen]]

I also '''highly recommend''' reading Figaro's useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information documentation]] if you are planning on using these sensors. I found it very helpful. They also provide [[http://www.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
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There are also links for an extended data sheet for [[http://www.figarosensor.com/products/2620Dtl.pdf | TGS 2620]], an extended data sheet for [[http://www.figarosensor.com/products/2442Dtl.pdf | TGS 2442]], and [[http://www.figarosensor.com/products/signal.pdf | signal processing]] and calibration notes for TGS 2442.
In addition, Figaro also provides useful [[http://www.figarosensor.com/products/common%281104%29.pdf | general information]] documentation and [[http://www.figarosensor.com/products/solder.pdf | soldering instructions]] on their website.
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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. \\
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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 some of the gases they detect in order of priority according to their data sheets. \\
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TGS 2442 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO)\\
to:
TGS 2442 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
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[+!!!Gas Sensors+]
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!!!Gas Sensors
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[+!!!Applications+]
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!!!Applications
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[+!!!Electrical Characteristics+]
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!!!Electrical Characteristics
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!!!Gas Sensors
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[+!!!Gas Sensors+]
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!!!Applications
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[+!!!Applications+]
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!!!Electrical Characteristics
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[+!!!Electrical Characteristics+]
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The Occupational Safety and Health Administration, [[http://www.osha.gov/ | OSHA]], has laws about acceptable amounts of gaseous chemicals that workers can be exposed to. These 'acceptable levels' are called Permissible Exposure Limits or [[http://www.cdc.gov/niosh/pel88/npelname.html | PELs]]. Companies are legally obliged to make sure their workers' exposure to a given chemical does not exceed that chemical's [[http://www.cdc.gov/niosh/pel88/npelname.html | PEL]]. The list of industries and settings where these sensors are used to maintain worker safety is very long and includes chemical plants, pharmaceutical production, fertilizer plants, automotive garages, biomedical and chemical research labs, healthcare facilities, dry cleaners, industrial kitchens, and many more.


[[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]]

[[http://64.233.187.104/search?q=cache:SE1glBo4BfQJ:ceeserver.cee.cornell.edu/esw/project_pages/documents/FeralDogs.doc+figaro+sensors+Natalie+Jeremijenko&hl=en&client=firefox-a| Autonomous Feral Robotic Dogs]]

!!!Electrical Characteristics
This report will cover four different models of gas sensors made by [[http://www
.figaro.co.jp/en/top.html | 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.
\\
to:
The Occupational Safety and Health Administration, [[http://www.osha.gov/ | OSHA]], has laws about acceptable amounts of gaseous chemicals that workers can be exposed to. These 'acceptable levels' are called Permissible Exposure Limits or [[http://www.cdc.gov/niosh/pel88/npelname.html | PELs]]. Companies are legally obliged to make sure their workers' exposure to a given chemical does not exceed that chemical's [[http://www.cdc.gov/niosh/pel88/npelname.html | PEL]]. These sensors can be used to control ventilation systems, turn on air cleaners, or to trigger alarms if gaseous chemicals reach dangerous levels. The list of industries and settings where these sensors are used to maintain worker safety is very long and includes chemical plants, pharmaceutical production, fertilizer plants, automotive garages, biomedical and chemical research labs, healthcare facilities, dry cleaners, industrial kitchens, and many more.\\
Changed lines 22-25 from:
TGS 2442 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO)\\
TGS 2600 [[http://www.figarosensor.com/products/2600pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
TGS 2602 [[http://www.figarosensor.com/products/2602pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Toluene| Toluene]] (C'_7_'H'_8_'), [[http://en.wikipedia.org/wiki/Hydrogen Sulfide| Hydrogen Sulfide]] (H'_2_'S), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Ammonia | Ammonia]] (NH'_3_'), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2620 [[http://www.figarosensor.com/products/2620pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')
\\
to:
In addition to worker safety, I found some more creative applications for these sensors.\\
Added lines 24-38:
Natalie Jeremijenko used them in her [[http://xdesign.ucsd.edu/feralrobots/ | Feral Robotic Dogs]] project in which she retro-fitted store bought toy dogs with these sensors and modified them to sniff out enviromental toxins.\\
\\
Huadong Wu and Mel Siegel at Carnegie Mellon's Robotics Institute developed an [[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]] using these sensors. I don't really think I need to say anymore about that.\\
\\
I plan to use these sensors in a project for the [[http://www.jennyjeanne.com/classes/wearables/?p=6 | Wearable Technology]] class. I hope to create an accessory that responds to air quality by changing shape.

!!!Electrical Characteristics
This report will cover four different models of gas sensors made by [[http://www.figaro.co.jp/en/top.html | 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 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO)\\
TGS 2600 [[http://www.figarosensor.com/products/2600pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
TGS 2602 [[http://www.figarosensor.com/products/2602pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Toluene| Toluene]] (C'_7_'H'_8_'), [[http://en.wikipedia.org/wiki/Hydrogen Sulfide| Hydrogen Sulfide]] (H'_2_'S), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Ammonia | Ammonia]] (NH'_3_'), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2620 [[http://www.figarosensor.com/products/2620pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
\\
Changed lines 5-6 from:
I purchased my sensors from [[http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]\\ Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
to:
I purchased my sensors from [[http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]\\
Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
Changed line 5 from:
Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
to:
I purchased my sensors from [[http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]\\ Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
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This report will cover four different models of gas sensors made by [[http://www.figarosensor.com/index.html | Figaro Engineering Inc.]]\\
to:
This report will cover four different models of gas sensors made by [[http://www.figaro.co.jp/en/top.html | Figaro Engineering Inc.]]\\
Changed line 10 from:
The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozen of different gases, some of which are better for us than others. Some are ok in small quantities, but not so good in larger quantities. Some are inert and some are flammable. Gas sensors detect amounts of certain gases in parts per million (a unit of concentration) in the immediate surrounding area. I found a pretty good explanation for parts per million (ppm) which I cut and pasted from
to:
The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozens of different gases, some of which are better for us than others. Some gases are ok in small quantities, but not so good in larger quantities. Some are inert and some are flammable. Gas sensors detect amounts of certain gases in parts per million (a unit of concentration) in the immediate surrounding area. I found a pretty good explanation for parts per million (ppm) which I cut and pasted from
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\\
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http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9993
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The Occupational Safety and Health Administration, [[http://www.osha.gov/ | OSHA]], has laws about acceptable amounts of gaseous chemicals that workers can be exposed to. These 'acceptable levels' are called Permissible Exposure Limits or [[http://www.cdc.gov/niosh/pel88/npelname.html | PELs]]. Companies are legally obliged to make sure their workers' exposure to a given chemical does not exceed that chemical's [[http://www.cdc.gov/niosh/pel88/npelname.html | PEL]]. The list of industries and settings where these sensors are used to maintain worker safety is very long and includes chemical plants, pharmaceutical production, fertilizer plants, automotive garages, biomedical and chemical research labs, healthcare facilities, dry cleaners, industrial kitchens, and many more.
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozen of different gases, some of which are better for us than others. Some are ok in small quantities, but not so good in larger quantities. Some are inert and some are flammable. Gas sensors detect the amount of a certain gas in parts per million (ppm) in the immediate surrounding area to the sensor. Parts per million is a unit of concentration. I really like this explanation that I cut and pasted from
[[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Ppm.html | Kimball's Biology Pages:]]
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to:
Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
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[[http://www.figarosensor.com/index.html | ThisWiki:/uploads/Reports/sensors.jpg]]\\
[--Picture from [[http://www.figarosensor.com/index.html | Figaro Engineering Inc.]]--]\\
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozen of different gases, some of which are better for us than others. Some are ok in small quantities, but not so good in larger quantities. Some are inert and some are flammable. Gas sensors detect amounts of certain gases in parts per million (a unit of concentration) in the immediate surrounding area. I found a pretty good explanation for parts per million (ppm) which I cut and pasted from
[[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Ppm.html | Kimball's Biology Pages:]]\\
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A unit of concentration often used when measuring levels of pollutants in air, water, body fluids, etc. One ppm is 1 part in 1,000,000. The common unit mg/liter is equal to ppm. Four drops of ink in a 55-gallon barrel of water would produce an "ink concentration" of 1 ppm.


The sensors I am reporting on are pictured below. Model [[http://www
.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
\\
[[http://www.figarosensor.com/index.html | ThisWiki:/uploads/Reports/sensors.jpg]]\\
[--Picture from [[http://www.figarosensor.com/index.html | Figaro Engineering Inc.]]--]\\
to:
A unit of concentration often used when measuring levels of pollutants in air, water, body fluids, etc. One ppm is 1 part in 1,000,000. The common unit mg/liter is equal to ppm. Four drops of ink in a 55-gallon barrel of water would produce an "ink concentration" of 1 ppm. \\
You can calculate percent from ppm by dividing the ppm by 1,000,000 and multiplying by 100
. So if you can detect 300ppm of ethanol in the air, the air is 3% ethanol, and you might be at TNO.
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http://www.simetric.co.uk/si_ppm.htm
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Gas sensors detect levels of various gases in the air.

The sensors I studied are pictured below. Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
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The air we breathe is made up of approximately 78% nitrogen, 21% oxygen. The remaining 1% is a mixture of dozen of different gases, some of which are better for us than others. Some are ok in small quantities, but not so good in larger quantities. Some are inert and some are flammable. Gas sensors detect the amount of a certain gas in parts per million (ppm) in the immediate surrounding area to the sensor. Parts per million is a unit of concentration. I really like this explanation that I cut and pasted from
[[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Ppm.html | Kimball's Biology Pages:]]\\
\\
'''Parts Per Million (PPM)'''\\
A unit of concentration often used when measuring levels of pollutants in air, water, body fluids, etc. One ppm is 1 part in 1,000,000. The common unit mg/liter is equal to ppm. Four drops of ink in a 55-gallon barrel of water would produce an "ink concentration" of 1 ppm.


The sensors I am reporting on are pictured below. Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
\\
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[--Picture from [[http://www.figarosensor.com/index.html | Figaro Engineering Inc.]]--]
to:
[--Picture from [[http://www.figarosensor.com/index.html | Figaro Engineering Inc.]]--]\\


http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9993

http://www.simetric.co.uk/si_ppm.htm
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!!!Gas Sensors

Initial report by [[~jk1667 | Jen]] 10/22/05 \\
Gas sensors detect levels of various gases in the air.

The sensors I studied are pictured below. Model [[http://www.figarosensor.com/products/2442pdf.pdf | TGS 2442]] (white) is pictured on the left and models [[http://www.figarosensor.com/products/2600pdf.pdf | TGS 2600]], [[http://www.figarosensor.com/products/2602pdf.pdf | 2602]], and [[http://www.figarosensor.com/products/2620pdf.pdf | 2620]] are on the right (silver).\\
\\
[[http://www.figarosensor.com/index.html | ThisWiki:/uploads/Reports/sensors.jpg]]\\
[--Picture from [[http://www.figarosensor.com/index.html | Figaro Engineering Inc.]]--]

!!!Applications

[[http://www.cs.cmu.edu/~whd/publications/imtc00.pdf | Odor-Based Incontinence Sensor]]

[[http://64.233.187.104/search?q=cache:SE1glBo4BfQJ:ceeserver.cee.cornell.edu/esw/project_pages/documents/FeralDogs.doc+figaro+sensors+Natalie+Jeremijenko&hl=en&client=firefox-a| Autonomous Feral Robotic Dogs]]

!!!Electrical Characteristics
This report will cover four different models of gas sensors made by [[http://www.figarosensor.com/index.html | 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 [[http://www.figarosensor.com/products/2442pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO)\\
TGS 2600 [[http://www.figarosensor.com/products/2600pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
TGS 2602 [[http://www.figarosensor.com/products/2602pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Toluene| Toluene]] (C'_7_'H'_8_'), [[http://en.wikipedia.org/wiki/Hydrogen Sulfide| Hydrogen Sulfide]] (H'_2_'S), [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Ammonia | Ammonia]] (NH'_3_'), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H)\\
TGS 2620 [[http://www.figarosensor.com/products/2620pdf.pdf | Data Sheet]] - [[http://en.wikipedia.org/wiki/Ethanol| Ethanol ]] (C'_2_'H'_6_'O), [[http://en.wikipedia.org/wiki/Hydrogen| Hydrogen ]] (H), [[http://en.wikipedia.org/wiki/Isobutane| Iso-butane]] (CH'_3_'CH(CH'_3_')'_2_'), [[http://en.wikipedia.org/wiki/Carbon_monoxide| Carbon Monoxide ]] (CO), [[http://en.wikipedia.org/wiki/Methane| Methane ]] (CH'_4_')\\
\\
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.myCodeSample | 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.