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Cool CCFL Voltage Bargraph — Parallax Forums

Cool CCFL Voltage Bargraph

ercoerco Posts: 20,260
edited 2010-01-23 21:40 in General Discussion
Just got my Parallax CCFLs and they're amazing even in their intended 12-volt function. But check the effect when you vary the voltage (into the Parallax inverter) from 4-8 volts: you get a fairly linear voltage indicator!
http://www.youtube.com/watch?v=1LkNmuupsvo·

Anybody think this is harmful to the inverter or lamp? No magic smoke released yet. Here, the inverter is hooked up to a power supply and I'm manually adjusting the voltage.

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·"If you build it, they will come."

Post Edited (erco) : 1/20/2010 12:43:34 AM GMT

Comments

  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-01-20 00:52
    Brill! I love it ..I might just have to get those CCFLs now .

    Peter KG6LSE.

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    "Carpe Ducktum" "seize the tape!!"
    peterthethinker.com/tesla/Venom/Venom.html
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    LOL
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-01-20 03:04
    You can also drive them from a Propeller DUTY mode output, using the circuit I posted here (or something similar):

    ····http://forums.parallax.com/showthread.php?p=851938.

    Think light sabers, volume level meters, equalizers, etc.

    I haven't detected any harm to the inverter from driving them this way. I think the reason this works is due to the wire that runs alongside the tube to feed the other end. This sets up a field that favors the wired end and excites the gas there before the rest of it can ionize.

    -Phil
  • ercoerco Posts: 20,260
    edited 2010-01-20 04:02
    Phil, you're always one (actually many) step(s) ahead of me. I never checked that thread, it sounded like that low-glow flexy Califor-Neon EL tubing. Pity your cool discovery (from last October!) got buried inside that thread. Well it's out in the open now, Pal, and I give you full credit !

    I like the 3-color units. I want to use a Stamp to switch it exactly to the 3 voltage steps where the colors change.

    Unless you've done that already, too???!!! [noparse]:)[/noparse]

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    ·"If you build it, they will come."
  • ercoerco Posts: 20,260
    edited 2010-01-22 06:04
    Video: BS2 Homework board switches voltages into 3-color CCFLs for a light show. Mucho fun to play around with.

    http://www.youtube.com/watch?v=7EOrtHYsgAE

    Fun fact: I'm using 3 of my my favorite little Aromat TF2-5V relays here to switch voltages. These 5V, 17 mA relays are being driven directly by the HW board's output pins, each which has an inline·220-ohm resistor, so the relays are operating off of 3 volts or less, and·~ 10 mA. Not all of these type relays will·work properly at this low voltage, these were hand-picked. Pretty sensitive stuff.

    CCFLs: http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/ccfl/List/0/SortField/4/ProductID/629/Default.aspx

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    ·"If you build it, they will come."
  • ercoerco Posts: 20,260
    edited 2010-01-23 05:19
    3 month-old Lindsey was diggin' the CCFL light show tonight, as sequenced by the Stamp homework board. She's a Parallax girl already! The pic shows her literally·unable to take her eyes off the light. A baby calming device, perhaps?

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    ·"If you build it, they will come."
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  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2010-01-23 21:40
    Sweet, I found the same thing when Ken gave me a set to try. Check out the series of pics at different voltages:

    http://forums.parallax.com/showthread.php?p=852508

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