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Controlling a 7-color blinking led with BS2 through LED's control pin - question — Parallax Forums

Controlling a 7-color blinking led with BS2 through LED's control pin - question

IceFireProIceFirePro Posts: 86
edited 2010-06-20 15:45 in BASIC Stamp
Ok,

I am getting further. I have connected my 7 color blinking led's anode and cathode to Vin (9V) and Vss.

What I want to learn is this: It also has a third, control pin (the led). In order to switch modes on the LED you need to briefly connect the control pin to VSS.

What wold be the way to control this via BS2? I tried to connect a transistor that would connect the control pin to Vss, but nothing happens.

Can i discharge the control pin into Vss directly in an IO pin ?

Comments

  • FranklinFranklin Posts: 4,747
    edited 2010-06-20 05:16
    Which 7 color blinking LED are you talking about? Do you have a datasheet we could look at? As long as you don't exceed the max current or voltage you can always pull a pin LOW which is pulling it to ground.

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    - Stephen
  • IceFireProIceFirePro Posts: 86
    edited 2010-06-20 05:37
    This is the RadioShack's 7 Color Blinking LED. Actually it has no data sheet, which everyone complains about on the radio shack's webpage! But this is what it does:

    It has anode and cathode and : a third "control" pin. When you run the diode, it goes through one cycle ob blinking and changing colors and stops - then you can switch through the different modes by shortly (via pushbutton) connecting the control pin to Vss (ground).

    I now want to do this with a remote control; which I have set up (IR receiver and code); but I need to be actually able to "push" this pushbutton with the basic stamp. So the ways to do this will either be to connect the LED's control pin through a transistor to ground; or to connect it to an IO pin. But for the second idea, I am not sure - the led runs now on 9V battery, so I am not sure what would be the electricity discharged into the IO pin. Also, if I do that, how can I control it : IO pins have two states "HIGH" and "LOW", but they have no "NO CONNECTION" state, right? Meaning, I can't briefly connect the LED's control pin to Vss and then connect it to nothing via an IO pin, right?
  • FranklinFranklin Posts: 4,747
    edited 2010-06-20 05:42
    Somebody said...
    Also, if I do that, how can I control it : IO pins have two states "HIGH" and "LOW", but they have no "NO CONNECTION" state, right? Meaning, I can't briefly connect the LED's control pin to Vss and then connect it to nothing via an IO pin, right?
    Wrong, read the help files in the editor for more info on pins.

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    - Stephen
  • ercoerco Posts: 20,256
    edited 2010-06-20 06:19
    If you·need help with a particular item, you·should always·help the helpers. Attach a link the item you're talking about.

    In this case it's··http://www.radioshack.com/product/index.jsp?productId=3060680

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    ·"If you build it, they will come."
  • Ron CzapalaRon Czapala Posts: 2,418
    edited 2010-06-20 14:13
    I bought one of those a while back and found this useful info:

    http://www.buzzillions.com/reviews/radio-shack-high-brightness-7-color-5mm-blinking-led-reviews?prRo=5#bz-model-review-tabs-list

    "With proper voltage adjustments I've achieved true 7 colors, yellow and white modes to adjust by till true hues are obtained. Lack of simple schematics is a bad thing for this L.E.D. but a little on-line research can go along way. The internal I.C. appears to be a 16 bit!! shift register with the letters *IWO240* on the bottom left corner. A "one shot power-on test cycle" that goes through single then multi colors and finally flashing through the two combos. But it wont flash automatically after that sequence is completed because it's ONLY a test. With a simple momentary N.O. push button wired from signal lead "looks like a /", to negative "Or the lead closest to the flat spot on the diode" you'll be in business.

    I used a 4066 quad switch and a 555 timer to "flash" the diode using the signal input when I want it to, the fastest you will get is about 14-16 hertz before the diode stumbles. And if you use more then one diode you will see that the continuous colorfade will NOT stay in sequence with each othor. Maybe 5 secs. and that's it due to each chip is as independant as the diode itself.

    This little jewel is pretty tough but dont overdrive it or you will heat up the I.C.s internal resistors. And I zapped one with almost painfull static discharge by accident and it still worked, assuredly now I'm more cautious ^,^

    Voltage wise I have had it up to 7 volts D.C. in off mode with 4 diodes in parallel with the voltage dropping to 3.2-3.7 in on modes, so voltage wise it likes what the package says pretty much. And YES you can hook it straight to 2 AA batts in series without a resistor if you like, 4.5 volts tops for a single diode BUT, Check to see if it runs cool or warm, then it's OK, IF you notice the temperature steadily rising for more then 30 seconds or it's hot to the touch...cut the power quick and add resistors or drop the voltage.

    My Electronics Learning Lab, Catalog #: 28-280, and a digital multimeter was used to investigate the possibilities, not to mention a good wealth of Parts, I.C. chips, and circuits written by electronics author Forrest Mimms III. And it's not limited by the parts it has either which is KEY! Good Stuff.

    Also I noticed an interesting thing when I used a power adapter for this project....but I will leave it at that."
  • IceFireProIceFirePro Posts: 86
    edited 2010-06-20 15:45
    Good stuff.

    Got it to work for me using a transistor connected to P8.
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