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Help with 2 electrode chemirestive film sensor

Discussion in 'Sensors and Actuators' started by Tammy, Dec 6, 2016.

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  1. Tammy

    Tammy

    2
    0
    Dec 6, 2016
    I am no electronics student. So pardon me if i asking a lame question.

    For a science fair project, I am trying to build a simple two electrode sensor with a chemiresistive film connecting the electrodes which will absorb volatile organic compounds in the human breath.

    The goal is to measure resistance change before and after exhaling breath on different subjects and draw a conclusion.

    To make chemiresistive film, we will using carbon and tetracosane hydrocarbon powder and bake in the 100 c baking oven for 30 seconds to make a thin film connecting the electrodes.

    Also we will need to make lot of sensors (atleast 100) for testing on different subjects.

    So we got this weird idea to use baking cups instead of PCB to perform our test. So the idea is we poke two copper wires into a baking cups (non-conductive and can withstand 100c for 30 seconds and cheap) with 2 electrodes 3 mm apart and make chemiresistive film about 10mm x 6 mm joining those electrodes and connect multimeter to the ends of the copper wire and measure resistance before and after blowing air on to it.

    Please let me know if this would work as an alternative to a PCB.
     
  2. Tammy

    Tammy

    2
    0
    Dec 6, 2016
    By the way, I am planning to put the sensor under bottom opening 125 ml bottle and blow air from mouth using a straw on the top opening of the bottle.

    The bottom of the bottle is going to have 2 holes for the 2 copper electrodes so i can connect digital multimeter to both ends to check resistance change while blowing air and still keep airtight.

    This way i can prepare multiple home based sensors for my high school science fair project.
     
  3. 73's de Edd

    73's de Edd

    2,848
    1,209
    Aug 21, 2015
    baking cups . . . . of paper . . .and interfacing a wire to it and then that wire, of which, a slightest flex would fracture and break the electro-continuity bond with the electroresistive blob.
    Cant see it . . . . just keep with the electromechanically stable PCB to wire connection with the THIN UNIFORM overdeposited chemical " film " (layer).

    HINT:
    Use single or double thickness BLUE masking tape tabs at each opposite side of the pcb
    for establishing height spacing references off the board.
    Place a drop of mix just short of the desired deposition area and then use a glass rod (glass eyedropper less its bulb) or HDPE rod (round orange peeler or plastic eyedropper (HDPE) to be used as a " rolling pin" rolling upon the spacer tabs, to uniformly deposit the mix.
    Special way to do that also . . . . as you are rolling , you are continually making a corrective lateral side shift to mimimize adhesion of the mix to the " rolling pin".

    Thasssssit . . .

    REF:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5107496/

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5107496/


    73' s de Edd

     
    Last edited: Dec 6, 2016
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