Introduction: Simple Music Light Show (lpt Led)

Picture of Simple Music Light Show (lpt Led)
Really simple & cheap light-bar, powered and controlled from pc ( over lpt port ).

It will cost you something about $10-20 to build this
( I had the plexi and lpt cable for free, so I only paid $3 for led torch and $3 for nuts and bolts )

= killer raito fun for money

video in action

video from testing

In real world is even better looking because eyes are slower than digital camera, so it is glowing nicely.

Step 1: What We Need

Picture of What We Need

8 colorful pieces of plexi-glass ( or you can use same color, they just need to be discrete, I used 10 x 7 x 0.5 cm )
2 large pieces of transparent plexi-glass ( I used 56 x 12 x 0.3 cm )
8 leds ( I ripped them off from one $3 led torch, basically use wide angle! (with 15 or 45 degree LEDs it is looking bad, use as wide as possible ), high power, white LEDs )
bolts and nuts
black spray
parallel port connector ( I used one from old printer )
sandpapers ( 200 & 400 )

I got the small pieces actually as testing samples from a company making plexi (, they gave them to me for free. Big thanks for them :-)

Step 2: Scheme & Testing

Picture of Scheme & Testing
Electrical scheme is really trivial, just connect leds to the LPT (parallel port) of your computer. Lpt outputs about 5V so if you are using white or blue high power leds you don't need resistors for them, just add 10-100 ohm for safety. ( if you are using red, green or other colors, use proper resistors acording to desired voltage, usually 200-300 ohm ). Longer feet of the led is anode (+).

I had to test if the plexi is translucent enough and if it is even working, right?

check video from testing on my desk..

In real world is even better looking because eyes are slower than digital camera, so it is glowing nicely.

Step 3: Drilling & Sanding

Picture of Drilling & Sanding

Let's put it together, I used chewing-gum like material to fix it in place.
And drilled about 40 holes. It is better with some vertical-fixed drill for better quality. And take it slow
with plexi-glass, or train few holes on dummy piece.

Even if you did carefully drilled all holes like me, there may be not-matching edges (foto3) after putting together. It will look better if you shape them to one line. First use 180 grid sand paper if you end with big gaps like me. Then use 250 grid. Finally you can play hour or so with number 400. Until it's looking perfect.

Step 4: Paint & Wires

Picture of Paint & Wires

Clean up all the mess from sanding.
Remove protection foil from inside side of the big pieces.
Mask it properly and paint thin line to cover cables and leds.
Wire it.

Step 5: Final Foto & Software

Picture of Final Foto & Software

Put it together and we are almost done.

Connect it to pc, sometimes it flashes randomly when booting.
If you are using speedfan, uninstall it.

For programmable effects I recommend you ( first half of my final video)
LPT LED EFFECT 0.9.4.beta

there are a lot of them, this is just example, you can select another one. Just search "lpt led". It can show your cpu / memory utilization, lots of effects, etc..

For music light show, you need a winamp plugin

a simple one

Diskolitez is more customizable
and here is my settings fot diskolitez if you want to try
you can even manage up to 32 leds (or big-lights) acording to plan on

If nothing happened try if you have right parallel port adress (378) set in bios.

And if you run any OS based on the NT kernel (ie- Windows NT, 2000, or XP), you may need an additional program called Userport UserPort allows you to control hardware resources (such as a parallel port), which is normally prevented in NT except by system functions. You will need to install then run UserPort and type "0x378-0x378" in the left hand box and then click "add". Then click "start" and "update". If you get a "Driver already started!" message, just click update. Now the plugins should work.

- solution found at

Step 6: Action!

Picture of Action!
In real world is even better looking because eyes are slower than digital camera, so it is glowing nicely.

have fun, hope you like my first instructable :-]


forever_flightless (author)2013-11-23

Can you make it Bluetooth so you can connect it to a phone 

karkox (author)2012-11-25

If I use this usb converter. He will work?

guddagudda2 (author)2012-04-07

why not making it into a usb instead of the other cable because many computers don't have that connection anymore?

shawndur (author)2012-01-04

can you use an ethernet cable instead of the parallel port

N1CK4ND0 (author)2009-06-23

It would be really cool if you made it so the LED's went on when you touched the individual plates!

joudas (author)N1CK4ND02011-08-18

yeah, or make it something like this :)

brigs164 (author)2011-08-17

is there a way to use 10 leds?

jgfresh (author)2011-07-09

i made one aswell:

rens23 (author)2011-05-02

do want!

eptgrant (author)2009-08-09

Hey quick question, I believe I've set mine up correctly, but 2 of the 8 LED's are permantly lit up. Any suggestions?

e-vad (author)eptgrant2010-11-16

go to the settings for those two lights, and make sure the first slider isnt at 0. i had the same problem, and all i did was put them at 1.

joudas (author)eptgrant2009-08-09

you mean even if you start program or winamp plugin? 6 is working right and 2 are lit up all the time? actually never had that problem, there are random blinking during pc boot and after that it usually stays all lit up until I started program or plugin...

eptgrant (author)joudas2009-08-09

2 lights are lit up constantly. it would be approx. the middle 2. so weird. just wondering now if it might be windows 7...

wes115 (author)2009-06-24

has anyone made one with all one color? im interested to see if it would look good or just blenf into a big.. blob. idk, i dont want alot of colors so i was thinking red blue red blue red blue ya know. but thnx man this looks great still not sure how to use the programs tho im not to goos at this stuff

singh1234 (author)wes1152010-11-08

not red blue but this also looks good. made it yesterday. very awesome instructable. = )

Kruegem (author)2010-10-10

Is there anyway to hook this up to a mac computer?

karthikcool90 (author)2010-10-06

wt will happen when we use extra LED's instead of resistors ???
like making a series of 3 LED's and connecting it to the pin ???

comsa42 (author)2010-08-24

I like this instructable sooo much i made my own version! And Made an instructable about it! :D

Kruegem (author)2010-08-22

closed grit or open grit sand paper?

Computothought (author)2010-06-12

Think I will try that.

acepilot32 (author)2010-06-04

could you use clear acrylic sheets with different colored LED's to get the same affect?

joudas (author)acepilot322010-06-04

probably yes, but diferent colors of leds means diferent resistor for each led to make sure they shine equaly and dont get burned from overvoltage.. and that acrylic still has to be "frosted/translucent" not just clear/transparent (if you know what I mean )

acepilot32 (author)joudas2010-06-04

I know how to frost acrylic. Does it really matter if i use different resistors?

joudas (author)acepilot322010-06-05

try it and let us konw :)

acepilot32 (author)joudas2010-06-05

I actually don't have a port on my computer for the computer connection so I'm going to do a static version with rgb leds

r_barnes (author)2009-07-06

where could you buy the colored plexi glass

robot+more (author)2009-09-29

could i use an USB cord

maroja (author)2009-09-13

how to connect this to the winamp..? to show the light show music..

joudas (author)maroja2009-09-13

download winamp plugin... just read the text man

Zem (author)2009-07-27

Is the parallel port connector male or female? Thanks.

osgeld (author)Zem2009-08-02

its female on the board, so you will need a male connector

yznaction (author)2009-07-26

Would it be possible to use a usb Parallel port adapter with this setup?

fwjs28 (author)yznaction2009-07-26

a usb port would require an extra piece, like a micro-controller...a Parallel port would be possible though with a similar set up (i am no expert in electricity nor I/0 ports so don't take my word as religion )

yznaction (author)fwjs282009-07-26

alright, i just ask because i only have usb ports on my laptop and I know there are a few companies that sell usb to 25 pin dsub parallels adapters

fwjs28 (author)yznaction2009-07-26

ahh, i would try the convertor...see what you can do

huang.wencong (author)2009-06-09

It would be more fun to create your own software . . Try using Visual Basic or Delphi.

grey House (author)huang.wencong2009-07-18

If you're into python there's an extension called pyparallel that might help. There's a great example code here:

Couldn't agree more. I'd like to see it in plain old C though...

artiem85 (author)2009-07-13

This is my first project so maybe this goes without saying but I was wondering what size wire is used for the connection between the lpt cable and LEDs and how do you terminate at both the port and LED splice points?

drew.adc (author)2009-06-06

It is a good idea to put in a resistor even if the supply voltage matches the rated voltage of the LED. It is there simply to limit current, so something like a 1 Ohm resistor will protect your LED's.

scgtrp (author)drew.adc2009-07-09

The resistor is there to protect the parallel port, not the LEDs. A new motherboard is a bit more expensive than a few LEDs, and you can easily kill your parallel port (and the motherboard, if it's onboard) by drawing too much current.

joudas (author)drew.adc2009-06-07

yea, you are right, fixed

wes115 (author)2009-07-02

ok so i made mine with 4 red 4 blue and it looks great. Only problem is i got a new computer used my old graphics card and harddrive in my new computer. the led's blink when starting up but when i run the LLC or any other program it doesnt run the lights. anythoughts on what to do? thnx

origamic12 (author)2009-06-18

How many bolts and nuts? and does size of the bilts and nuts matter?

joudas (author)origamic122009-06-19

basicly I used 2 for each square on top to hold it leveled, and the same amount at the bottom to match visual, size is M4. But you can go bigger/ smaller, depends on taste :-)

Sowee (author)2009-06-14

So, with this project i can control 23 LEDs?

Vladmakesstuff (author)Sowee2009-06-18

Yes you can control 23 LED's but this will require some other special made software to use the 8 D pins on the LPT port , and also you would need some shift register chips .

matstermind (author)2009-06-17

my LEDs just stay on, the program won't work. i need some help.

ZachPosey (author)2009-06-09

i want to make one of these sooo bad but my laptop doesnt have a printer port, is there any way to make this thing controllable over usb or something like that?

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