Hackaday links: June 13, 2010

Painting with light

[Jo0ngle] wanted a fun toy and an easy conversation piece. He painted a square on the back of his door with some glow-in-the-dark paint. Now he can draw on it using a blu-ray laser or a UV flashlight. Either way, the effect is quite pleasing. [Thanks Justin]

Resistor decoder rings

This resistor reference card allows you to spin a wheel and dial in the resistor color code for easy reading. We know, you have the simple act of reading resistor code down cold by now. This is still a fun idea that you might use if you’re ever helping someone get into electronics. [Thanks Osgeld]

Resistor bending template

Speaking of resistors, [Jerome] helped us out by designing a resistor bending template. He’s actually marketing himself at the same time. His bending template is folded from one of his business cards, which he came up with after being inspired by some of the unique business cards we’ve covered in the past.

Fake stained glass using old PCBs

[Agg] floated some old PCBs to his friend [Dan] the mason. [Dan] proceeded to turn out an amazing looking stained glass window unit using the colorful leftovers. The picture above doesn’t do it justice, you have to click through to see the real art.

Monovelo monowheel

[Ernst] asked if we’d heard of the Monovelo monowheel. Well we hadn’t. It’s a human-powered vehicle where you sit inside of one large wheel. We don’t see ourselves building one or riding one, but we enjoyed watching someone else do so. We’d like to catch somebody commuting to work with one of these. Seeing this in the bike lane will brighten up anyone’s day.

23 thoughts on “Hackaday links: June 13, 2010

  1. wbeaty — January 22, 2007 — Got glow-in-dark paint? UV keychain flashlight? Combine the two.

    I’d also like to say that the UV LEDs are in fact dangerous. Most of the emission is not viewable by people so it’s brighter than it looks. Be careful.

    You could use a blue LED instead of a UV one. That will excite most glow in the dark stuff too.

  2. wbeaty – Don’t worry. The commercially available UV-Leds are totally safe! I know this, because I’ve tested them. In fact – I’ve been hunting the so-called dangerous ones to use them for erasing UV-Eproms. Unfortunately (and fortunately for people in general) UV-Leds are as safe as normal UV-Disco lights, the same kind you use for checking upon false bills etc.

    I also have UV-measuring equipment, and my tester says 0,01 uv on the UV-leds, and 4-5 uv on direct sunlight. So the sun is more damaging than a single UV led – hence – totally harmless.

  3. the resistor bending card is pretty cool, been thinking about making one out of a old AAA card or something to accommodate other hole jump spacing (not like that hasnt been done a dozen times already)

    right now I just use the “heel” of my thumb to bend the leads right at the entry point, which gives you the hole spacing of whatever sized resistor your using, but not always convenient when using perfboard prototyping

  4. >I also have UV-measuring equipment, and my tester says 0,01 uv on the UV-leds, and 4-5 uv on direct sunlight.

    You are measuring both wavelength and intensity? What units of measurement are you using?

    Unlike “black light” UV tubes that have a broad range of wavelengths, UV LEDs have a narrow notch of emissions. You may not be measuring peek output.

    Just because that one UV wavelength does a crappy job at erasing your eprom does not mean it won’t fry your rods and cones over-easy.

  5. @JoOngle
    Ok, so you’ve got about 404nm of wavelength.
    But a normal bluray laser diode has 100mW of Power.
    It’s a class 3B laser !! (read the safety instuctions for that)
    A laser is safe up to 40 µW of power.
    1 mW is safe for about 0.25 seconds.
    a 100mW direct hit into the eye is damaging the eye permanently and instantly.
    and now think about reflections, the laser is 10000 times more powerfull than the safe class 1 laser. that means, a 10% reflection of that would still be a class 2 laser, and by that, still be harmfull when exposed longer than 0.25 seconds.

  6. I love resistor value cards! I collected them for a short while.
    A sad and somewhat embarrassing fact: resistance bands were one of the last things I learned (memorized) in electronics. I guess not having EE exams and a card in my pocket made me lazy, OR it pushed other memorized info out finally lol.
    Who DOESN’T cringe when you bump the resistor container. That multi-colored spaghetti is gonna take some time to get back to normal lol.

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