I don’t care how great your touch typing skills are, when you’ve been drinking beer and jumping around on stage for an hour you’re going to need some light to help you trigger that next sample. Fortunately for laptop performers an increasing number of current machines are coming with integrated lighting solutions. Whether it’s the Macbook Pro’s backlit keyboard or the Thinkpad Thinklight these gadgets are a boon for electronic musicians.

My primary VJ machine is a Thinkpad so I’ve got no lighting issues there, but I also have a second Asus laptop for running Live or generating visuals. It has no keyboard light and I haven’t picked up a commerical LED lamp, so at the moment my keyboard technique is to feel for the f bump or to bend down and squint wildly. I did have a bunch of LEDs and USB cables waiting around for the right project, but it seems the project may have been waiting for me.

Australia’s Silicon Chip magazine published these cheap and cheerful instructions (via Make) in 2002. My electronics knowledge is minimal but perhaps a couple of LEDs could be chained to obviate the need for complicated things like resistors.

Alternatively: a bunch of LED throwies could be attached to nearby ferrous gear and angled to provide an audience of helpful fireflies.

  • Neat. Will have to investigate. if you used a few leds and run them through a gooseneck mic holder, you could have a pretty bright anglepoise!

  • Chaining multiple LED will increase current use (each draws about 20 mA). Most USB ports are only spec'd to deliver 100 mA.

    Resistors are used to reduce the 5V power supply down to the 2.5 to 3V requirments of an LED, so connecting a 3V LED to 5V power without a proper resistor in place will probably just destroy it.

    That said, quite a few companies produce LEDs with built-in resistors, although the price is higher.

  • Eric

    James –

    Jaymis is right: you can put a few LEDs in series to eliminate the ballast resistor without increasing the current draw. If you put too many in series though, none of them will turn on very brightly. I'd limit it to 3 at most, and it would be best to experiment to find what works best for the LEDs you have on hand – they're all going to have unique current/voltage requirements.

    You are right that putting a couple of LEDs in parallel without the resistor would just increase the current drawn and probably burn out both LEDs.

    Using a ballast resistor is the safest and most repeatable way to control the LED brightness while ensuring that you don't overload anything.

    Trust me – I R an electrical engineer. 🙂

  • enjoi

    Just to clarify,

    the resistor is actually used to limit the current. with no resitor the current will not be limited and the LED will blow quite quickly. Putting a number of LEDs in series increases the voltage required to power them (~2V each), but they still need a current limiting resistor

  • ToS

    There is a problem with this design, there is nothing that will hold the led light in place. There should be one thick wire runing along other that will hold the light the way you position it.