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tcs230-db respons — Parallax Forums

tcs230-db respons

ricki_kurniawanricki_kurniawan Posts: 2
edited 2009-03-23 03:18 in Accessories
hi there,

i want to ask every one that familiar with tcs230-db. I want to make color detection with tcs230-db. i use colour print paper for sample. I have connected tcs230-db with atmel micrcontroller atmega 8. i use pulse count to measure the respons of tcs230-db. I change the filter setting every some sampling periode. There is some weird respons. I see every about 10 to 20 sampling data with 1 second sampling periode the value is change. can you suggest me, what must i do?

Comments

  • Craig EidCraig Eid Posts: 106
    edited 2009-03-16 07:37
    Have you tried posting a query on the AVR freaks website (avrfreaks.net)? They have a wealth of knowledge and may provide some specific information to your AVR problem.

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  • ricki_kurniawanricki_kurniawan Posts: 2
    edited 2009-03-23 02:23
    Thank's for your comment and your advice i will ask them.

    How about the respons of tcs230-db. is it have a good repeatibilty for long time measure? or i must measuring the colour at short of time.

    example i measure color that value is 423, i continue to measure it for 50 times sampling and it take 1 minutes. Is the value constant 423 or it will be change.

    Thank's for your kind'nes to answer.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-03-23 03:18
    The TCS230-DB should be stable, assuming a stable ambient envronment. The sensor chip itself has good long-term characteristics, and the LEDs are current-regulated to provide a constant light output over varying supply voltages. However, if the LEDs get moved, or the ambient lighting conditions change, you may, of course, get readings that vary a bit.

    Here are some things you can do to minimize variances:

    1. When first powered on (and occasionally during use, if necessary), do a white balance using a standard reference. For the ultimate accuracy and repeatability, consider a mechanism that will enable a white balance to be taken automatically before each reading.

    2. When taking a reading, include a reading for each color with the LED off, which can be subtracted from the corresponding LED-on reading. This will help to cancel any effects of ambient lighting.

    3. If the LEDs are subject to varying mechanical stress, anchor them in place, so the leads don't flex. This may be as simple as applying small beads of hot-melt glue between LED and lens holder, or as complicated as making a fixture cut out from a piece of fiberglass laminate. I've done the latter, and it works well.

    -Phil
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