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The room has 10,000 red/green/blue LEDs in a 4" grid covering
approximately 1000 square feet. They are on 1" x 20" pcb boards
("strips") that are mounted into wood slats that have perspex (acrylic)
openings for the LEDs to shine through. Each LED has 255 levels
of brightness for the red, green, and blue, which smoothly mix so each
LED is separately controlled to create millions of possible
colors. Besides the excellent color control, this installation
and overall project had to:
Work with the remarkable Madrix
software to create a wide variety of sound-synchronized effects
Be modular and have easily swappable electronics, so any
failures can be quickly
Have straightforward wiring and powering, since it is in the
UK and I'm in Oakland so all the installation needed to happen without
me being around
Have test modes at multiple points to diagnose every
conceivable problem from a bad LED to a bad Ethernet cable to a loose
connector to a firmware bug
Work with standardized lighting protocols (DMX and ArtNet),
Work the first time, with parts available in large quantity
immediately - no waiting more than 1 week for anything. From initial
proposal to the prototype design to production manufacturing to
LED boards + custom cabling + control system hardware with completed
ArtNet firmware was 7 weeks. Which is crazy. While also
doing other client work.
I'm happy to say my hardware design achieves all this and is
There are two main parts of the installation: the LED "strip" boards,
and the control boards. The overall flow is the Madrix program sends out the
complete lighting data for all the LEDs (10,000 * 3 colors = 30,000
bytes of data) at 30-ish frames per second. This goes from a
Ethernet port on the computer to an Ethernet switch, which routes it to
15 different control boards, each of which runs up to 7 sets of 17
pairs of LED "strip" boards. This means commodity (i.e. cheap)
computer networking hardware and cables are used to get this data
distributed in a (relatively) easy, reliable manner.
The LED strip board design:
In order to keep costs as low as possible, but also use standard
lighting protocols (in case the control board couldn't be created fast
enough), the LED strip boards use DMX. There are actually two
designs, the "Left" (with electronics and LEDs) and the "Right" with
just LEDs. They plug together. By having all the
electronics on just the Left, several $thousand was saved. Most
of the area to cover is done by having 17 of the Left+Right pairs
connected with 26-conductor ribbon cable, forming a single DMX universe
(510 of 512 possible channels), and runs at 5V @ 11amps peak.
Video of the prototype is here. This
proved the "basic DMX universe unit" would work, and manufacturing
started immediately. In order to have these "DMX universes" fit
in the actual space, the design is such that the Left board can be run
without a Right, and also either Left or Right can be cut with tin snips to fit exactly in
the area needed. Nifty!
A single Left+Right strip-pair:
Close-up of the electronics, which are on the backside. The LEDs
are on the front of the board, facing the room.
Electronics are: Microchip PIC18F24K20 @ 64Mhz, receiving DMX from ST
Microelectronics ST3485ECDR 3.3V RS485 RX/TX and running 30 channels of
8-bit, 220Hz PWM dimming with 2 ON Semiconductor CAT4016VSR-T2
16-channel constant-current LED driver chips. Electronics runs at
3.3V from the very noisy 5V power via a diode and bulk filter
cap to a 3.3V regulator. Boards are standard 1Oz copper 10 mil
trace/space with black
soldermask, because black always looks good on long, thin circuit
boards hanging out in a club.
The LEDs. (amazing pretty little white squares that
cost 78c each if you buy 3000 at a time. Osram LRTB G6TG)
So that's the Left+Right LED "strips". Each has 5 LEDs,
electronics on the Left one, plugged together they make a 1" x 40"
strip with 10 LEDs at a 4" spacing, and each strip-pair has uses 30 DMX
channels (which 30 of the 512 in a DMX universe selected by DIPswitch),
runs at 5V @ 0.65amps peak, has 3 built-in test modes, and is
impervious by design to power supply noise and voltage dips, to work
perfectly even 100 feet from the power supply with a multitude of
cables carrying hundreds of amps pulsing all around. No
problem! 17 of these strip-pairs have their power and DMX signal
connected together by custom-made ribbon cable with connectors at 4.5"
spacing (4" between each strip-pair to maintain the overall 4" grid,
and 0.5" of extra cable for slack).
But the installation requires nearly 60 of these DMX universes!
How to get +5V @ 11 amps and all the DMX data to 60 of them?
Let's talk about DMX distribution first.
DMX has been around a long time, and it works great. But there is a
scalability problem. Most clubs and theaters need one or maybe
two DMX universes for all
their lights and lasers and fog machines and whatnot, because a single
multicolor, spinning light needs just a couple of DMX channels to
control it. At 512 channels per DMX universe, you can run a lot
of whizzy stuff on a single universe. However, if you want to run
10,000 3-color (R/G/B) "lights", you need 30,000 channels. 60 DMX
universes. The normal way to get DMX lighting data out of a
computer is a little USB box that gives you 1 DMX output. I don't
know if plugging 60 of them into one computer would work, and even
if it did initially, that's a lot of things to fail and cables to come
loose and mysterious Windows problems to fix and settings to configure
and yuck. Not acceptable.
This scalability problem of DMX is completely solved by sending the DMX
lighting data over Ethernet in a format called ArtNet,
now gotta get your lighting data out of Ethernet and output as
standard DMX, and you need 60 outputs. No problem... if you're rich. Ethernet to 12
outputs: $2500! Want to buy 5 to run all this? Or
Ethernet to 8
outputs: $1200, and we need 8 of them. There's no way to
get from Madrix (or anything that outputs ArtNet) to 30,000 DMX
channels for less than $8500 - ish.
Money like this is crazy talk, because ArtNet to DMX isn't hard.
And that $8500 was just not going to happen with the budget.
That's more than the LEDs cost! So I did what any self-respecting
solopreneur electronics designer would do of course - I designed and
made 15 of my own in 2 weeks:
This thing is the evaluation board (the nice looking rounded corner
green board) for a newish chip I've been wanting to design with (the
LM3S6965) literally and figuratively bolted onto a board I made that
has 7 DMX output connectors and power coming in. As labeled
above, you connect the Ethernet (back to that Ethernet switch the
computer running Madrix is wired to), and then plug in up to 7 DMX
universes, which run on cat5 cabling because it is almost ideal
electrically and dirt cheap. Then spend 5 long rushed days
getting up to speed with a new chip, with a new toolchain, creating 7
serial ports in firmware ("bit-banged" 250kbaud), significantly
tweaking an opensource
including a workaround for its
legacy 4 DMX universes per IP address
limitation (by adding multi-homing to uIP, i.e. 2 IP addresses with one
MAC), and voila. For less than $2K we have 30,000 DMX
channels going to around 60 universes over commodity Ethernet switches
and cabling. They could have run an installation twice this
The last big aspect to the design...powering everything:
each of the 60 DMX universes needs +5V @ 11amps when it is on
full. This is a lot of power. There is the significant
problem that 11 amps of current down a wire of any appreciable length
causes the voltage to drop... fast. So the design was done with
an eye on wire lengths and thickness (thicker = less voltage drop, but
more expensive, sometimes much more). The alternative would be to
use a higher voltage (say, 12V) but then each LED strip-pair would need
more electronics to work, which is more cost/complexity/potential
failure, but thinner wire and less of it could be used (lowering wire
cost and making installation simpler). Electronics design is all
about tradeoffs, with a dozen ways to do anything beyond the trivial,
and the right answer is the one that balances the relative importance
of many often competing goals. Without painting yourself into the
corner if something unexpected goes awry with your best-laid plans.
The right answer here was: simpler electronics, straightforward but
more and slightly spendier wiring, lower overall risk, everything
available off the
shelf. So each DMX universe of 17 strip-pairs has its own pair of
thick-ish wires to a +5V power supply, and each power supply runs 5 DMX
universes, and each feed out of the power supply has a separate 13-amp
circuit breaker for the 11-amp (peak) feed. There is an ArtNet to
DMX control board with each power supply, and it sends the DMX signal
to each of the connected LED universes.
What it looks like - here's about half the ArtNet to DMX boards (in a
column on the left) and power supplies (silvery boxes in the center
column) and circuit breakers (in vending machine esque enclosure), in a
next-door side room/closet that has (a)
sweaty partiers spilling their red bull with vodkas into 220Vac power
And there you have it! Add ever more sophisticated swirly visuals
and have thousands and thousands of people dig it for 20 years to come!
Many thanks (I wanna give a shoutout
Lenore @ EvilMadScience
for the project referral Erupting
Volcanoes that gave me 2 more days to finish (I'm not kidding! no
flights = no international air shipping = a bit more time)
Tam @ Meritronics where all
the LED strips were made in a big rush due to crazy schedule,
compounded by 4-day USA customs delays
My brother Chris(website) for programming
and bubble-wrapping something like 1500 of the LED boards in a big big
Stacey Rolland for making 70 pieces of ribbon cable with 17 connectors
Steve & Steve @
the club for their patience
and wiring me many $thousands and believing me that it was all gonna
and especially my sweetie Laura
for putting up with the scramble and the work and me sweating it all
for weeks on end!
Thanks for reading!
I design stuff like this all the time, if you have a project you need
custom work for, drop me a line.
Also see DMX LED drivers for sale.