2009 RGB Pixel Project

Hard to believe that four years have passed since the first DMX RGB Pixel Project was cobbled together.

For 2009, we’re working on something completely different.  These don’t yet have a name – or even some sample photos – but here’s a sneak peak of the feature list.

  • System brightness to be halfway between the point source and a ‘classic’ big pixels.  Design uses 3 each wide-angle red, green and blue emitters.
  • Component count is *significantly* lower than any of our existing designs and 100% surface mount, which keeps the assembly robots fast & happy.
  • Boards are daisy chainable with cat5 jumpers OR hard-soldered connections, up to 255 per string, provided that +12v supply is re-injected from time to time.  Current draw remains stable at ~ 60 mA per pixel.
  • Position Agnostic!  No need to address each individual pixel.
  • Head-end controller handles all DMX massaging, addressing and color updating.
  • Working on a plastic ‘overmolded’ enclosure for a totally weatherproof system.
  • May even feature a plastic ‘jewel’ similar in size/shape to a standard C9 lamp.
  • Circuit board size is 2″ x .6″
  • Head-end controllers will be daisy-chainable using industry-standard  XLR-4 ‘Color Scroller‘ cables, which combine a shielded, twisted pair for data and a heavy gauge pair for power.  Last year’s cable harnesses (1 x cat5, 1 x 18 gauge pair) worked well but took way too long to assemble.

I’m very excited about these, actually.  The assembly shop is working on a test batch of 100 pieces, which should be delivered in a week or so.

Pictures & video clips to be posted as they’re available.  To be kept abreast of the latest developments, join the ‘Insiders Club’ at the top right corner of this screen.

DIY Pixels Rev2

This is a second revision of the DIY pixels we’ve been selling for the past year or two.

Notable changes:

  • Support for field addressing per SRM’s jumper code, which is discussed in further detail in the DIY Christmas DMX Section.
  • Nifty white soldermask.  Good for reflecting LED light back toward the eyeball.

There was some decent interest in a completely through-hole design. Some folks wanted to build their own pixels but weren’t comfortable with surface mount components.

This board receives DMX through a pair of RJ45 connectors in parallel. A SN75176 translates the differential data into a single-ended signal that the PIC can process. 5 x 2N3904 transistors drive 5 banks of LEDs.  The intention was to drive red, green, blue, amber and white LEDs.

The LEDs are arrayed as follows:

W A R G B W 

Useful PDF Files:

I currently have about 70 of these boards for sale.  $3.50 each or 10 for $28.  Send an email to John AT response-box.com if you’re interested.

Sorry, all boards have been spoken for.  We can certainly order more if there’s interest.

Field Programmable Source Code!


It used to be that we’d write the pixel’s DMX address in firmware, then compile and program each PIC.  It worked well but got tedious.

Several thousand pixels later, we’ve got field-programmable source code up and running.

Short version: the PIC listens for an alternate (non-zero, dimmer data always is zero) start code in the DMX stream.  That start code is followed by a special packet of data which contains, among other things, the new start address plus a checksum.  The chances of this particular packet occurring naturally in your lighting rig are one the order of 1 in 2^80.  That’s a 1 followed by 24 zeros.  At the time of this writing, this number is slightly higher than the new US national debt.

‘Programming’ packets can be sent at any time.

The new address is, of course, stored in the processor’s permanent memory.

The address is also displayed by the pixel on power-up. The red LED flashes once (.2 S duration) for each ‘hundred’ in the pixel’s address or once (.6 S duration) if there are no hundreds.

Likewise for green / tens and blue / ones.

Channel 1 = long | long | short

Channel 12 = long | short | short short

Channel 304 = short short short | long | short short short short


So now, all pixels can be factory programmed with the same firmware.  This saves us a tremendous amount of time.

Firmware works for point source, ‘mini’ and ‘classic’ pixels and is totally backwards-compatible with anything we’ve ever shipped.  It will also work in 3-channel mode on the through-hole DIY pixels.  Haven’t had time to mess with the 5-channel version.

Contact us for a .hex file if you want to re-burn your own pixels.  Or send ’em back and we’ll be happy to re-flash them with this new code.  Programmers are $46 and will be available soon in the online store.

Watch it work in the clip below. Click the arrows in the bottom right corner of the video frame for a full-screen version.

Setting Pixel Addresses in the Field from Engineering Solutions Inc on Vimeo.”>

Boring technical bits:

A normal DMX packet looks something like this on a ‘scope:


Where 0 is the start code, which is then followed by between 1 and 512 8-bit channel values.

Our pixel programming packets have 11 bytes and look like this:


‘P’ is the upper-case ASCII character having a hex value of 0x50. ‘I’ is 0x49, etc. HH is the high byte of the new address. LL is the low byte of the new address. CHECK is the 8-bit sum of the high and low address bytes, overflow ignored.

Programming packets which don’t precisely match this format are rejected.

The pixel firmware doesn’t currently error-check the new address, so values between 513 and 65535 are technically valid. They’ll just never light up in any production lighting rig. However, the programmer firmware is range limited to [1 510]. What good would it do to park a 3-channel pixel at 512?

Complete 2008 Point Source Pixel Rig For Sale

EDIT 3/9/09 —— The System Has Been Spoken For.  Thanks! ——–


So I’m working on some new ideas for the 2009 Christmas season.  To get everything R&D’d I need to free up some capital.  And though my wife thinks I’m crazy, I’ve decided to sell the entire rig used for the 2008 build.

At its most basic level, the system includes

  • 200 Point Source pixels, assembled and tested & guaranteed to run.

These little friends have been selling briskly in our online store at $7.50 each.  By my calculations, that prices the bare pixels – wiring, connectors and programming time excluded – at $1,500.

However, I’m reluctant to break up the system.  So to sweeten the deal, I’ve decided to add the following bits and pieces:

  • One Isolated DMX splitter with XLR-5 ‘in’ and ‘through’ jacks, plus 8 output drivers and custom wiring harness tails.  These have been selling well for about $80 each.
  • One Isolated DMX splitter with XLR-5 ‘in’ and ‘through’ jacks, plus 4 output drivers and custom wiring harness tails (my rig used two DMX universes, hence the double splitters).  Retail price is $60.
  • 6 Data /  Power cable harnesses, each measuring between 80′ and 160′ long.  I paid $0.60 per foot for the two types of wire, plus about $4 for the polarized, locking Molex connectors on either end.  Total wiring harness length is very close to 600′.
  • 6 DMX Splitter / Ribbon cable feed boards.  These convert connect the power cable harness to the ribbon cable runs and ensure that power and data are cleanly distributed.  They probably cost $15 each to build and test. 
  • 6 sets of ribbon cable with connectors mounted on 8″ centers.  Each cable contains between 10 and 42 point source pixels.
  • One +12v @ 12A switching power supply – more than beefy enough to run the entire system – with custom wiring harness pigtails.  Cost me $30 at www.weirdstuff.com a few years back.


  • I’ll re-flash each of the pixels with our brand-new firmware.  It will take about 3 hours, but I think it’s worth it.  The new firmware allows the a pixel to be re-addressed in the field – without using a computer.  It also boasts a 150 Hz refresh rate on the dimming routine.  This is 50% faster than the current firmware allows, and it makes fades and chases even more smooth.


  • I’ll throw in a brand-new hand-held pixel Programmer / Tester module.  It contains a tiny LCD plus several pushbuttons for easy navigation.  Setting and confirming a pixel’s address takes only a few seconds.  Once I get these assembled in bulk, they’ll be priced at $48 in our online store.  

So when the dust settles, this is a complete, ready-to-install RGB lighting package.  Everything is included and easy to configure.  You just provide a stable source of DMX and some imagination.

The system is guaranteed to arrive in working condition.  Your purchase also includes unlimited tech support via email, plus 5 hours of live, on-the-phone troubleshooting if you get stuck for any reason at all.

If I add up the prices of everything listed above, the total very nearly reaches $2,150.

However, I’ve decided to let it go for $1,839.  

I have to move quickly because our accountant will be very, very irked if he finds out what I’m up to.  

You should move quickly because things for sale here often don’t last long.  In fact, I’ve already emailed everyone who is a member of our exclusive ‘Insider’s Club’ (you can join at the top right corner of this page) and fully expect that one of them will swoop in and grab the gear at an incredible discount. 

So if you’re interested or have more questions, send me an email and we’ll talk.  Address is ‘john AT response-box.com’

* Note that there’s still some snow on the roof here, and I’m not going up to retrieve the high bits until everything is bare and dry.  It shouldn’t take more than another week if the current weather trends hold.

Below are a couple photos which show the wiring harness and ribbon cable adapters in more detail.  Click a photo for more.



Point Source Pixels For Sale

UPDATE 2/2/09 – The string of pixels has been sold.  Thanks!

I’m selling one  ‘test’ string of point source pixels.  These are assembled and fully functional and have otherwise never been used.

The 25 pixels are mounted on 8″ centers on 10-position ribbon cable.  Since each pixel has a 10 pin male header, the cable can be easily and inexpensively replaced if desired.  Note that this is the same pixel spacing I used on the house this year.

Included in this package are the following:

  • 25 x 10mm Point Source Pixels
  • Ribbon cable with female headers on 8″ centers
  • Ultra-tiny DMX splitter and power combiner module
  • 5 pin male XLR connector for DMX input
  • 2 wire leads for power input.  Power supply is +12V, tightly regulated.  For full brightness, plan on ~ 70 mA per pixel total.  NO power supply is provided.
  • System guaranteed to arrive in working order.
  • BONUS: Unlimited tech support via email
  • BONUS: Up to 1 hour free tech support via telephone

Note that presently only 1 system is available for sale.

Pixels are programmed to DMX addresses [76,77,78], [79,80,81], … [145,146,147] respectively.  I’ll reprogram them to any other range for an additional $15.

Price is $179 + freight.  First come, first serve.  Send an email to john AT response-box.com with ‘I want the Pixel String’ in the subject line.  All major credit cards are accepted, and international shipping is no problem.


Point Source Pixels – Fully Installed!

What a day!  This morning I drove downtown to get another 200′ of power and data cable.  I’d previously used 400′ of each for the two lower rooflines, the arch and the garden lanterns.

I finished and tested a second 8-way DMX splitter, because the upper and lower runs are assigned to separate universes.  Then, I weathersealed the remaining 100 or so pixels for the three upper runs.  

We started installing at 5:30 and were finished a few hours later.

The test pattern we ran during installation – and which is shown below – toggles between green with red sparkles, red with green sparkles and blue with white sparkles.

All told there are about 200 point source pixels and 19 ‘classic’ pixels mounted in the garden lanterns.

Click a photo once for medium size, then a second time to see in a larger size.

Will post video clips once I’ve found a 3-CCD camera that has decent dynamic range.

Point Source Pixels – Halfway Installed

Here are some pictures I grabbed halfway through the installation.  

The low parts of the house are done.  The high parts of the house are terrifyingly out of reach.  Will work on those later this week.

There are 100 point source and 19 standard pixels in the garden lanterns installed so far.  That makes 357 channels of DMX-512.

Click a photo one for medium size enlargement, then a second time to see it full size.

Point Source Pixel – First Run


[click to enlarge]


Point Source pixel. Based on the original RGB design but with a 10mm RGB LED.

I’m really happy with this design. Adding some 1″ clear heat shrink tubing will make the design waterproof and safe to use outside. Of course, it’s meant to be driven by a DMX Offset Machine, described elsewhere on this site.

The YouTube clip below is characteristsicly choppy, but in real life the colors are crisp and clear. The transitions are very smooth and the white light ‘strobe’ effect is very convincing.

To get a decent video exposure, I placed a 100W desk lamp directly above the pixel while shooting. This way, there was a reasonable balance between the LED light and the ambient light.

All current used by this device comes through the 78L05 regulator, making the system much less sensitive to voltage drops in the cable. Power supply of 7-12V DC, 70 mA per pixel, will work wonderfully.

The LED throws a neat shadow 10′ across the workshop onto the opposite wall.

Buy bare circuit boards for $3 each if you’re interested.
3/28/08 Further Experimentation 

I chained 8 of the pixels together, just to see what would happen.

Wiring is more arduous than soldering the components in place! Each pixel has two sets of terminals in parallel with each other. This makes daisy chaining relatively simple.

I used 22 gauge shielded cable with 5 conductors: DMX ground, D+, D-, Pixel Power, Pixel Ground. Wires connected to the top and bottom of the circuit board. Then, the board lays flat.

Finally, I put a piece of 3/4″ clear heat shrink tube over the entire assembly. A small hole was punched in the center to let the LED peek through.

The ends aren’t completely sealed, but adding a few small pieces of 3/8″ heat shrink would close them up nicely. Waterproofiness is very desirable.

Coming soon: Video clips & photos of the chain in action.


Bill of Materials:

  • C1   .1 uF 10v 0805 ceramic
  • C4   10 uF 25v 0805 ceramic
  • C5   1 uf 10v 0805 ceramic
  • JP1  5 pin .1″ header, or leave blank                
  • JP2  5 pin .1″ header, or leave blank                
  • LED  RGB LED, 4 pin, common cathode                   
  • PGM  5 pin .1″ programming header, optional          
  • R1   80 0805 package        
  • R2   80 0805 package    
  • R4   1000 0805 package    
  • U$1  78L05 SOT-89 package                               
  • U1   PIC 16F688 SOIC-14 package                          
  • U2   MAX485/SN75176 RS485 transceiver, SOIC-8 package
Buy bare boards for $3 in the online store.
Find a PDF copy of the schematic here.





Pixel Installations in the Field

Here’s a small (but growing) collection of projects which include our DMX pixels.

mrpackethead from New Zealand sends this photo and video clip.  Pictured are 160 of the ‘classic’ RGB Pixels, based on daisy-chaining cat5 network cable.

If you’ve used pixels in a creative or exciting way, we’d love to hear about it.  Send your pictures, links or video clips.