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contesting in the dark with LED light

Discussion in 'Computers, Hardware, and Operating Systems' started by K8MCN, Apr 20, 2012.

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  1. K8MCN

    K8MCN XML Subscriber QRZ Page

    here is a neat way to make a little LED light out of one of your old USB cables, an LED and a resistor--great for lighting up the keyboard when logging/contesting in the dark

    i am not connected with the web site--just found it while searching for LED projects
  2. KK4AMP

    KK4AMP Ham Member QRZ Page

    Or you can pick up a similar rig at Dollar Tree if one is close by. :) The one I grabbed there is on about a 10" gooseneck, so it can be positioned to light the keyboard up pretty well, but only from the side that is closest to the notebook USB ports.

    Yours is a neat quick project if someone has the stuff laying around though! I definitely like your light placement better.
  3. K2NCC

    K2NCC Premium Subscriber QRZ Page

    Or you could just learn to type!

    ...better yet, just get a real light that doesn't require a computer to be on to use it.
  4. K8ERV

    K8ERV Ham Member QRZ Page

    I checked my box and only found dark leds. Bummer.

    TOM K8ERV Montrose Colo
  5. KF5FEI

    KF5FEI Ham Member QRZ Page

    Someone sells a War of the Worlds looking USB light that does a great job of illuminating the keyboard -- it has more than one LED and a diffuser to spread the light.
  6. W5ETT

    W5ETT Ham Member QRZ Page

    Actually that would be a ded.
    Kent W5ETT
  7. KF5FEI

    KF5FEI Ham Member QRZ Page

    Darkon emitter.


    I've been working on a project that requires controlling 32 LEDs, (A binary clock/calendar). So I checked out the shift out tutorial on
    I could not easily locate a 74HC595, but a bit of reserch shows that Jaycar has the Texas Instuments 74HC164
    A bit of poking round and checking the Datasheet, and messing with the shiftout tutorial, I've finally got it working LED Bulbs Wholesaleblue led strip
    led tube lights

    These chips do not appear to need a latch signal, I've used the shiftout tutorial code, with the latching deleted. It appears that by having the Clear pin permanently on HIGH, the clock signal is all that is required.

    Attach the Clock signal to Pin 8, Data signal to pin 2, attach Pin 9 (VCC) and 14 (CLR) to +5V, do not connect the latch, and the single chip Shiftout code will function. (you can delete the Latchpin lines in the code)
    Other chips in series are connected the same way, except for the data line, which is daisy chained from pin 13 to pin 2 (Yes, both the LED and the Serial in Pin are connected to Pin 13), and again the shiftout two chip code will work (again you can delete the latching lines). I've currently got 4 of these chips working in Series, giving me my 32 LEDs to play with.

    You can perhaps set up one serial array for each channel, and drive 30+ 3 channel LEDs from only 6 pins on the Arduino.


    First off I'm not really sure how "holographic" this is going to be.

    Is a 2x2 matrix just 4 LEDs? That is 8+ pins for dual color? This sort of depends on the device you choose.

    I think you need a stepper motor (probably bipolar) to control a mirror, not an "optical sensor." Alternatively you can use a motor that steps back and forth at a known frequency (or write a program to do this).

    The key to this is probably going to be persistance of vision (POV), that is that you don't need to leave the LEDs "on" all the time, but rather turned on/off quicky to give the impression that multiple LEDs are on. To do this with an LED matrix you'll need a Johnson counter (CD4017 can be used for this). The counter "enables" one of the rows of the matrix and then you output what LEDs you want on. So you need somethign like 6 data lines for a 5x7 matrix (not bad for 35 leds). 1 counter trigger and 5 LED controls. I have some code for it lying around that I can post if you're interested. LED Bulbs Wholesaleblue led strip
    led tube lights

    You can control multiple arduinos with SPI or some other kind of inter-IC protocol or even just simple 1/0 on the digital lines to trigger an action on another arduino (say....move motor x degrees).

    Read up on optics and POV (look at barcode scanners), and draw up some kind of design.


    If I can someday grow a plant using let's say 10 watts instead of say 50watts, wouldn't that be a good thing?

    Or are you saying that because my plants are adapting to different light (like not having green) that this is bad too because it's different than the sun? I've read lots of books that say green is not used. The number of biological study end-results is like flipping a coin. Keep reading articles until you find one that agrees with your view. This is why I'm actually trying it and not just talking and reading about it. All indoor lights are different than the sun...I think.

    I know it's early in the LED technology stage for them to replace conventional grow lighting, especially in large growing and commercial situations. For smalltime hobbyists like myself, I believe it is feasible for a few plants and I'm trying to see if what I believe is so, not just reading about other people saying it isn't.
    LED Flood Light Supplier
    flexible led strip lighting
    LED fluorescent lighting
    Also there's a little environmental side note to LEDs. They don't pollute the earth with heavy metals and other chemicals like the millions of other bulbs we are disposing of everyday. I think LEDs are a step in the 'keeping it green' direction.
  11. WA9SVD

    WA9SVD Ham Member QRZ Page

    A local hardware store had "desk lamps (small. to be sure") for $1.00 also (apparently, subsidized by the local Electric Co.) Goose neck, but came with an AC adapter, and could also operate off 3 AAA batteries. It contained a strip of six "white" LEDs. They later came out with the same deal, but "soft white" color LEDs, which weren't quite as harsh on the eyes. I couldn't buy the parts for three or four times the price! (And my IBM laptop HAS an LED light built into the display to illuminate the keyboard.) If I have the time, I can build a small voltage regulator circuit to power the "desk lamp" from 12 Volts, and even include a dimmer function, as the LED's tend to be quite bright. Perfect for Field Day.
  12. WA9SVD

    WA9SVD Ham Member QRZ Page

    Those LEDs are valuable. Don't they prove the speed of dark is faster than the speed of light?
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