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Alcohol Gas Sensor MQ-3


Vendor's Description: 

Description: This alcohol sensor is suitable for detecting alcohol concentration on your breath, just like your common breathalyzer. It has a high sensitivity and fast response time. Sensor provides an analog resistive output based on alcohol concentration. The drive circuit is very simple, all it needs is one resistor. A simple interface could be a 0-3.3V ADC.

Please review the datasheet for conversions to ppm then Wikipedia.org for BAC.

Features:

  • 5V DC or AC circuit
  • Requires heater voltage
  • Operation Temperature: -10 to 70 degrees C
  • Heater consumption: less than 750mW

08880-03-L_i_ma.jpg 

Description: This alcohol sensor is suitable for detecting alcohol concentration on your breath, just like your common breathalyzer. It has a high sensitivity and fast response time. Sensor provides an analog resistive output based on alcohol concentration. The drive circuit is very simple, all it needs is one resistor. A simple interface could be a 0-3.3V ADC.

Please review the datasheet for conversions to ppm then Wikipedia.org for BAC.

Features:

  • 5V DC or AC circuit

  • Requires heater voltage

  • Operation Temperature: -10 to 70 degrees C

  • Heater consumption: less than 750mW

Make your own breathalyzer! This could be fun to use with a robot. You have to be drunk (or sober I guess) to play with a remote control car, robot, etc. I hope to eventually make a robot that can make mixed drinks. I could use this sensor to see if the user is drunk. If so, it pours water. If not, it pours the drink HEAVY.

 

http://www.sparkfun.com/commerce/product_info.php?products_id=8880

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whats a heater voltage?

They call it heater voltage because its the voltage that supplies the heater.  The heater dries the sensor element and gets it to its optimum temperature.  If you look at the curves in the datasheet you will see that it is most susceptable to relative humidity (moisture) and temperature.  So this attempts to dry it out and keep it at a constant temperature.  It also says to preheat it for over 24 hours to make sure its the most accurate it can be, which probaby won't happen on a battery powered device.

that is likely for extremely precise measurements. Most breathalizers take 1 minute from when you turn them on until you are supposed to blow. This allows the heater to warm up and dry the sensor off. A moisture sensor added to measure moisture and alert the user when the unit is dry enough would help ensure readings were accurate.
i still don't get it...why do they call it heater voltage and not, say, voltage needed to operate?
engrish translation...
I am assuming the sensor heats itself to operate. Maybe it has to be warm to detect the alcohol level.

Perhaps OddBot could use one of these on his BoozeBot.

http://letsmakerobots.com/node/2641

I've seen these at the local electronics store, there are also carbon dioxide (CO2), carbon monoxide (CO) and hydrocarbon (HC) sensors but some are expensive. I was thinking you could make a sort of electronic nose with these. At this point though, BoozeBot will have to wait, he's a long term project anyway.