Step 6: Wire up the 8 LED Strands

I chose wire wrap as the wiring method for this project because:
  1. it’s cheap
  2. there are no toxic fumes
  3. there is no risk of overheating and destroying LED’s
  4. it’s easy to undo, so repairs are easier
  5. it’s relatively quick to do
  6. it’s as reliable as soldering – perhaps more reliable, since there’s no risk of cold-soldered joints
  7. the wire is so thin that it can be threaded into the gaps between the foam matrix pieces
If you are not familiar with wire wrapping, Wikipedia has a detailed introduction to the technique.  I was a bit worried that the 30AWG wire would be too thin to handle the current running through the matrix.  I consulted some tables on the Internet, I found that 30AWG solid wire has a resistance of 105.2 Ω/1000 ft. I estimated an upper bound of 4 ft of wire, so that’s ~.4Ω – probably insignificant for this application. Next, I found that the current carrying ability (Ampacity) is estimated at .144A by most tables, but one actually had it listed at .86A. The LED’s I used run at a maximum of 20mA per color. In a column, a maximum of 1 LED at a time is lit, so it’s definitely in spec. On the other hand, if a whole row is driven w/ the with all 3 colors lit, we can end up with 8 x 3 x 20mA = 480mA. This is way over the .144A spec, but below the .86A spec. I decided to just try it, and if I encountered problems, I would put multiple wires in parallel for the rows.  After testing, I found that using single wires for the rows worked fine ... they did not heat up at all.

The schematic diagram for a common anode 8x8 RGB matrix is depicted above. We are going to wire our matrix, composed of 5mm LED's, in the same fashion.

We need a total of 8 strands of 8 LED's.  Each pair of LED's is connected with three 4" pieces of wire. The anode is the lead which is slightly longer.  In my photo above, the pins, from left to right, are Blue/Green/Anode/Red.

The red wires connect the red channel,  the white wires the green channel, and the blue wires the blue channel.  4" may sound a bit long, since the cells are only 2" wide, but I when you account for stripping the wire on both ends, and leaving enough slack to manipulate the LED's in while assembling the grid, 4" is a good length.  You will need 49 4" pieces of wire for each color - 147 pieces total.  While working on this step, I discovered a few things which make for a quicker and cleaner job:
  1. orient the pins of your LED's the same way while wiring them (e.g. blue pin on the left, red pin on the right)
  2. connect the R/G/B wires between each pair of LED's before moving to the next LED.  At first, I was connecting all the reds, then all the blues, then all the greens.  This method was a bit messier.
  3. spread the pins apart a bit before wrapping.  Otherwise, the wrapping tool will get caught on the adjacent wraps as you try to insert it 
  4. start the first wrap about halfway into each lead
  5. when connecting the second wire on each lead, just stack the wrap against the previous wrap.
Note that the anode pin is left unconnected at this stage.  This is because the anodes form the rows, which are perpendicular to the R/G/B cathode wires, which form the columns.
Is it possible to put a 330 ohm transistor on all wires of the R/G/B pins, like you did on the 5x5 coffee table. So i dont have to worry about leds being burnt or shorting my Arduino/Colorduino. Could you also explain me how to hook up the Colorduino with a Arduino Leonardo (clone).<br><br>Thanks in advance.
<p>Iv managed to get this running fine from my MacBook, but im struggling to get RGBmtx to run on raspberry pi, using the linux version. I have tried downloading processing and running the source code through there, but I cannot get it to work. Any tips on getting the software to run on a Raspberry Pi?</p>
I haven't tried running it on anything other than Windows. If it's having trouble finding the Colorduino, have a look at Colorduino.pde. The function openPort() scans for the serial port. Perhaps you can try hardcoding the actual port name into that function and see if that works.
I cant get the software to open at all on raspbian.
<p>Try this: <a href="http://cagewebdev.com/index.php/raspberry-pi-running-processing-on-your-raspi/" rel="nofollow">http://cagewebdev.com/index.php/raspberry-pi-runni...</a></p>
Ok this step is a little bit too complicated for me... I just want to control my 8x8 RGB Matrix with this software, so which code do I upload on my arduino? And were should I put RGBmtx.pde? I'm on a mac... Please give me a detailed step by step answer so that I can comprehend the single steps.<br><br>Thanks a lot!
RGBmtx.pde runs in Processing on your Mac. You need to download and install it. Follow Step 17 to load ColorduinoSlave.pde into your Arduino.
<p>Hello,</p><p>I am using a Mac and having a hard time getting RGBmtx to see the Colorduino. I am totally new to this. I am using a USBtiny which works to upload the slave sketch. I then have a Arduino Duemilanove board with the chip removed and connections from the Arduino Reset to DTR,TX to TX, RX to RX. The Arduino was getting power from the USB so i didn't use the 5V and ground connections. RGBmtx still says No output device found, running in standalone mode., Do I need to edit the Serial speed settings? If so where can I do this on the mac. Where is the place to edit the line of code. Sorry for the basic questions. Just having trouble with RGBmtx...</p><p>Thanks!</p>
<p>dunno if you have solved this already, but I was having the same issue. The reset pin needs to be connected for programming the board, but remove it before starting up RGBmtx, then the software should see the </p><p>colorduino on startup. I Also programmed the board with Arduino IDE 022 which has the right serial buffer, to save me messing around with too much in the Arduino software. (I am still extremely new to this whole thing and really dont understand most of what I am doing) </p>
<p>It took a couple of days as am very new to programming and arduino, but finally I got it working with the RGBmtx software. Now i just gotta figure out how to make it standalone. Eventually i want to be able to DMX control it. Thanks for the tutorial, defiantly the most comprehensive I was able to find. </p><p>In order to make this work I took the ATmega chip out of the Arduino chassis, and used the chassis as a USB to serial adaptor to program the colorduino directly. Is there any way of saving completed bitmaps onto the Arduino chip and utilising this to send the data to the colorduino rather than a computer? </p>
<p>Really nice work ! Thanks for sharing, keep on going, that's great</p><p>I rarely sign in to comment stuff, but i did it just to say how i was amazed and find this creation really nice.</p>
<p>I've read &quot;Instructables&quot; for quite a long time, but I gotta say Sir, you &quot;forced&quot; me to create an account just so I could comment on your work here. It's easily the best, most thorough &quot;how to&quot; tutorial I've ever seen here. You really know what you're doing and how to explain it. Impressive.</p><p>I don't plan to make one of these but you gave me some great ideas I'd been looking for for a while for another project. So thank you. Again, impressive. :)</p>
<p>will this work going 5x13 or can it only be 8x8? </p>
5x13 is 65 LED's. The Colorduino can only handle 64.
<blockquote>You needn't be super precise</blockquote><p>Unfortunately with this material it doesn't work like that ... 2mm cutting rabbets/slits with 3mm material thickness isn't a helpful combination ;) A dremel has to be used to widen all 96 slits.</p>
<p>Since you're using dibond, won't the aluminum short out the LEDs when you press them into the slits? I guess you have to cut wider slits, insulate the wires, and then hot glue the LEDs in.</p>
<p>I'm going a different way, cause of 140&deg; angle diffuse leds... On the backside a plate will be mounted, holding all leds which are facing toward the front. Right now the soldering part has to be finished, which will take &quot;some&quot; time ;)</p><p>I will keep you informed!</p><p>Btw.: Thanks alot for this great guide, lincomatic!</p>
<p>Dibond (3mm) is used instead of foam ... more than once i was thinking about stopping and using foam like lincomatic did ... ;)</p>
<p>You, my friend, have incredible patience! Looking forward to seeing the completed build!</p>
<p>Hopefully i don't have to take it apart again, cause the connections are very tight/strong (2mm slits / 3mm material) Much ironing left to do ...</p>
<p>Nearly 20m cuttings with circular saw (cause of the dibond material used) had to be made.</p>
<p>I finalllly finished wiring and building everything and testing my LEDs and power supply today. I was planning to power the array from the screw terminals, but when I went to attach the power supply I realized the colorduino I was sent did not have a switch to slide between &quot;header&quot; and 'terminal&quot; power sources. I was able to find a picture of both (so clearly they manufacture it both ways?) and have included it below. The one on the left is what every tutorial seems to depict and somehow I ended up with one like the righthand picture. I was curious what to do in this situation- will powering it through the terminals without the switch in place cause a problem to my the Colorduino or my LEDs?</p>
<p>I heard back from iTead and their reply is below: </p><p>&quot;We <br>have soldered 0R resistors on that position of the switch. You can add 9V <br>or other power supply on VIN pin.&quot; </p><p>I powered my array with 6V 1A through the screw terminals and it works perfectly.</p>
<p>The image quality on this is miserable (sorry!) but since this was a gift for someone, I don't have it around to take a better picture of. I'm happy with how it turned out. Used a Lexan enclosure for the array, with black foam board instead of white, and vellum sheets inside to diffuse the light I used black glossy spray paint on the bottom 2.5&quot; to hide the wires/colorduino/usbtinyisp programmer.</p>
<p>just FYI, the itead product links no longer work</p>
I can load the colorduino slave sketch to the colorduino, but rgbmtx says that there is no device found. <br> <br>Any suggestions?
I discovered the source of my communications error! When RGBmtx is launched it was resetting the serial port connection to the Colorduino, causing it to not see the Colorduino. <br> <br>Instead of plugging my programmer directly into the Colorduino, I used female to female cables and connected GND, VCC, RXD, and TXD. I did NOT connect DTR. By not connecting DTR, I prevented the serial port reset from affecting the Colorduino, and RGBmtx was able to see it!
<p>Thanks! That fixed my problem, too! :)</p>
<p>Glad to help!</p>
<p>Still new to the whole Arduino, Colorduino thingy, but thanks to you, I am able to use the RGBmtx to create some animations that work on the Colorduino! I used the animation code from Adafruit to do another Space Invader animation, but I don't know where to send it to you. Thanks!!!</p>
cool! send me a pm and i'll tell you where to send it.
Hey, Congrats for the great idea!<br>I&acute;m building mine and would like to know if there are any changes if I use a 24awg wire instead of the 30awg one...<br>Thanks!
Will this work with an arduino UNO rather than Duemilanove?
I have a problem with rgbmtx. I connected Colorduino, and the matrix of LEDs, to the PC via Arduino Duemilanove (without microcontroller). However, when using rgbmtx, there is a random delay in the display of frames. it is as if some frames were skipped, as during the animation LEDs rx-tx arduino blink correctly but the frame does not show all on the matrix. anyone have any ideas as to the reason for this? thanks
I just love this project and I really want to make one as a coffee table like in the picure I found on google. But there is one problem i would like to solve. In you instructions you said that if its not connected to the computer it can only display the plasma program because the memory is to small to hold other sketches. Now is my question if there is any way to increase the memory ? A external memory I can connect to it or something like that ? I've been searching on google without succes. It would be a shame if I had to connect my coffee table to my pc just to put something else on there then the plasma or to make it react to music. Thanks
I was wondering, did you take that picture or did you get from google?
Did you read my post ? Apparently not. It is in the first sentence.
I sort of skimmed through it I wasn't really awake yet
Would the microSD breakout board be an option ? How would I connect this and program it to make it work ?
Yes, you need to store the animations in files on the SD card, instead of feeding them via the serial link
oke thansk I'll give that a try
really cool lincomatic
I'm having some trouble getting RGBMtx to recognize the device. I have the Colorduino connected via USBTinyISP and the ColorduinoSlave sketch is uploaded (the plasma works, but only if the USB is plugged in as well). Any tips to get RGBMtx to recognize?
What resistor did you use? It looks like you have a large one hooked up to your Colorduino.
I didn't use any large resistors. The current limiting is all done on the board.
me podr&iacute;as ayudar como hacer un texto en colorduino hasta ahora solo he logrado poner letra por letra pero es mucho el espacio entre ellas, es asi. <br> for(j = -7;j &lt; 7;j++) <br> { <br> DispShowChar('u',255,255,255,j); <br> delay(i); <br> } <br> for(j = -7;j &lt; 7;j++) <br> { <br> DispShowChar('d',255,255,255,j); <br> delay(i); <br> } <br> for(j = -7;j &lt; 7;j++) <br> { <br> DispShowChar('i',255,255,255,j); <br> delay(i); <br> } <br> asi se pone letra por letra pero quisiera meter una palabra completa como hacerle te lo agradecer&iacute;a mucho.
Also, what USB adapter/parts do I need in order to connect to my computer?
What parts did you use to power the Colorduino? Can you post a link to the power supply and power adapter you used? I am buying all the parts for this project
Hey Lincomatic, thanks a lot for this tutorial. I followed all the construction aspects, but for software I designed all of my own. I used the Rainbowduino V3 which has a built in USB and I feel is much easier to work with, and I didn't have any kind of programmer. Since I wanted it to play frames even when it's not connected to a computer, I designed my own GUI kind of like RGBmtx (Mine has some better features: play mode, ability to have any color, etc). I also hooked up an SD card reader to my Arduino, and I'm sending all the info over i2c. It's all really straightforward, I am a total amateur at electronics and programming and this is my first project I've spent any significant amount of time on and I'd like to share it with people. I'd be happy to make an Instructable showing people how to do all this but I want to make sure you're okay with that first. I would give you credit and direct people to your tutorial for steps 1-14, and then I'd walk them through the connections and how to setup the software for my method. Let me know if that's okay, thanks. <br> <br>Here's a picture of the GUI by the way: http://imgur.com/syhIxqs <br>(you can tell where by the scroll bar is at in the Processing window that I put a lot of time into this ;D)

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Bio: For more information on my projects as they develop, visit my blog: http://blog.lincomatic.com
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