2011-02-13

Breathalyzer #2

THE FINAL VERSION POSTING OF THIS PROJECT IS AVAILABLE


Finished the circuitry of the breathalyzer
:D
I will have to install this in a casing
I think I am just going to Burberry wallet box

Schematic Diagram
Used this wiring diagram for my MQ-3
Codes:

The coding is not perfect
took me about an hour
:(
I don't think this project deserves any more effort
since the cheap alcohol sensor is not accurate

Moreover
I can always reprogram my micro-controller
even after finishing the product.

The only thing I have to remember to do is
for the final product
install a jumper that allows me to stop feeding power to
the sensor's heater

Will be using this for the next EE drinking session

Pictures of the prototype in operation:
Sleeping Mode (This is when the system will save as much power as it can)
This is when the system waits for the sensor to "boot".
This is when the users "blow" lol BAC is calculated and shows on the LCD
This is when the device "intellectually" make a suggestion. Based on BAC and its effects

UPDATE: Fixed BAC calculation after building the enclosure. Will keep updating... after each drinking session


By Joe Kwuen

8 comments:

  1. Hello,

    We are a retailer of breathalyzers and we are in the process of designing our model of breathalyzers.

    Are you interested in assisting us? If so, please drop me an email at marketing(at)precisionbreathalyzer.com

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  2. plz provide the exact circuit useed in it n pcb daigram ...

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  3. plz send me the circuit diagram. here is my gmail id: raj.morap@gmail.com


    thanks in advance.

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  4. This comment has been removed by the author.

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  5. can you plz send the complete code with the header files.gmail:- gihan9988@gmail.com

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  6. Hey may i know what is the formula u used to convert the voltage data you are getting from the MQ-3 into Blood alcohol content value?

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    Replies
    1. ... you should forget about getting a good accuracy measurements with these sensors.

      have fun and try calibrating it yourself like I did :]
      drink a beer... measure yourself, then compare with a bac calculator online.

      I think the best measurements can be achieved by sampling multiple times over a short period of time then averaging the value.

      try plotting your measurements...

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    2. hey there and sorry for my question.I understand what you said about accuracy that the MQ3 is cheap and so the results are poor but can you explain me why you use *0.0005 ?? and no for example 0.0001 or 0.0002 or....?? Is this an experimental result??

      thank you very much

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