# COMMUNITY : FORUMS : SQUARE PEGS

## LED Matrix Wall

Hey everyone!

THe artist Erwin Redl is very well known for his "LED Matrix Wall"

I went to go see it this weekend, and I wanted to know how it was done, sadly noone there knew :'(

So Im passing it on to Instructables! Help a newb create a wonder in his room!

Now i dont get how it is set up at ALL

i always thought the bottom needed to be connected to a negative...

can ANYONE help describe how this works, as you can see the bottom of the line, is a weight.

im so confused!

Im just trying to power as many LEDS as possible, and this seemed like a better way then my drawing with a white background...

justrelax7 years ago
maybe in the weight part there are soils...maybe?
Proteus7 years ago
They appear to be in a parallel configuration rather than series: something like this (picture)
7 years ago
There's no reason that the chains of parallel LEDs couldn't themselves be in series. If there were 27 chains, each chain would have over 3v (at 85vRMS of 120vAC). This should be plenty to power all the strings without any power conversion.
7 years ago
=] nice!
I didn't even think about it... Serious case of the "analog avoidance syndrome" I got from computer engineering course =D
mu0p (author)  Proteus7 years ago
i dont quite get it... :'( how many leds per each chain etc? im kinda lost
7 years ago
Well... The lenth of the chains isn't too important. Since each green LED uses about 20mA at 3.5v. That means 27 chains of 50 LEDs each would pull less than 1 Amp at 120v. Double the chains in parallel using a 1 Amp diode to each set at opposite polarities (half-wave rectifier for each set) with the other set and It'll pull less than 2 Amps at 120vac. You could reduce the number of chains to 25 to supply 3.4v ( RMS) per LED string. This would give you and array of 50x50 or 2500 LEDs pulling about 2 Amps at almost full brightness. There would likely be a bit of a flicker since you'd be sending a pulsating 60Hz supply to the LEDs.
7 years ago
Come to think of it, since each set of 1250 LEDs are using the oposite phase of the 60Hz, the entire set would only up about 1 Amp.
7 years ago
He could have disguised the resistors behind each leds by using some sort of led-casing... anyway that`s my guess...
justrelax7 years ago
LED Installation with Fiber-Optics
mu0p (author)  justrelax7 years ago
one room had fiber optics, but not like the pictured above.. these were strands of leds soldered to the 22 gauge copper wire, they went straight up to that track on the ceiling, which of course i could not see :'(
7 years ago
The lights would get dimmer towards the bottom (single strand) or the hangers thicker towards the top (multi strand).
I don't think so, and mu0p would surely have noticed this?

L
lemonie7 years ago
Well, you went to see it, you had the best opportunity to figure it out.
As Proteus I should think that both power rails are fed down from the top as he describes, but current management (e.g. resistors) can be done up top.

L
mu0p (author) 7 years ago
No, they are like my second drawing. There is nothing on the bottom connecting to the next string, its just a weight on the bottom. On the top is a track of some sort, and each line is individual. Nothing is touching the next line, the way its set up, is the track is on the top, and each row consists of (2) 22 gauge copper wire with the led in the middle of course. then at the bottom of each row is a weight to keep it staying in the same place. (SEE second picture, you can KINDA see the wire, and the weights at the bottom.) Thnx for your input!!!