Detector Monocular

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While working to create an electronic color sensor for our project, Shannon Molloy, a mechanical and electrical engineering student from Wentworth Institute of Technology, developed a convenient way to hold filters in place while blocking the surrounding light from the sensor. Her "filter monocular" is a low cost, durable, and flexible tool that may be used in classrooms and science centers.

Step 1: With a sharp knife, carefully cut an angular opening in the bottom of a plastic film canister.
Notice that the opening extends over half of the bottom.

Picture of the bottom of a film canister with an angular opening cut out

Step 2 : With a sharp knife, carefully cut a slot near the bottom of the canister that is parallel to the opening you cut on the bottom of the canister. Cut slightly past half the diameter of the cylinder.

Image of the top of the canister with a hole cut parallel to that of the bottom

Step 3 : Slide a gel filter into the slot, and you are ready.

Film canister with a gel filter in it

View from one side of the film canister

Purple gel filters that may be used for detecting plant stress:

    Medium Purple Filter by Rosco (#049) 
    Mauve Filter by Lee (#126) 
    Orchid Filter by Gam (#995) 
    Sour Grape Filter by Apollo (AP3250)

Extension Activities

    Substitute additional color filters to study the color of shadows, scattering of colors in the sky, looking at the health of skin, etc.

    Also, dark blue filters help golfers find their golf balls that are in a field of flowers (rather than paying the retail $40 for a pair of glasses).

Back to Plant Stress Detection Filters

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