NerdKit LED Array Build

With the forums at the NK site having the problems, it has made me realize that it would be good to have the projects I built available in another outlet… One that I can control.  So the next few posts will be essentially old projects I did a few years ago.

The 1st is my build of the Nerdkit LED Array project:

In case anyone is interested, I thought I’d post the progress start to finish of my marquee.
I built mine from scratch using the following. Materials:

(1) Piece of laminate flooring cut to 5″ x 19-3/4″
(2) 60 light strands blue LED Christmas lights (Purchased mine at Wal-Mart)

alt Blue LED Lights

Black spray paint
About 2Ft of ribbon cable (old floppy cable split to 17 conductors)


23/64″ drill bit (Size may vary based on lights purchased)
Center punch
Cordless drill
Soldering iron
Wire cutters
Wire strippers
Heat shrink tubing (various sizes)
Wire ties

The construction began by laying out a 3/4″ x 3/4″ grid on the back side of the laminate.  I then center punched and drilled all the holes with the 23/64″ drill.  Try to keep the drill as straight as possible when drilling.  I then cleaned the back side of the board and spray painted it black. (sorry I don’t have any photos of the layout and drilling process)

Once finished, the board looked like this.

alt Board top alt Board bottom

I then cut the light strands apart.  When cutting the strands apart, unwind the wires as you go.  The LED’s are run in series so there are some long continuous lengths of wire that can be used later for the marquee assembly.  After the LED’s and sockets were separated from the strands, these were the bonus pieces left over.

alt Blue LED's after cutting them apart alt Bonus bits

Notice I got 3 long wire sections, 2 resistors (in the green tube shaped pieces) a plug and socket from each strand.

After I had all the lights separated, I looked them over.  On the strands I purchased, there was a mark on one side of the socket.

alt Socket mark

On all but a few of the lights, this side represented the anode of the LED.  There were a few that were backward though.  I did go through all of them to make sure they were all set anode to striped side.

I then began the process of installing the LED’s in the board keeping the stripe on the socket facing the same direction on all of them.  This configured them anode to cathode as needed for the column wiring.

alt Installation progression alt Installation progression alt Installation progression alt Installation progression alt Installation progression alt Alignment

Once the LED’s were all in place, I began the daunting task of soldering all the wires.  I first soldered each of the rows skipping each column pair as I went.  I then soldered the column wires.

alt Beginning Column soldering alt Almost done alt Finally done

At this point, I was ready to test.  To do this, I connected all the row wires together and hooked an alligator clip jumper wire to it.  Then one at a time, I connected a column wire to another jumper.  I then connected the jumpers to 5vdc with a 1k resistor in series.  At this point, one column lit.  I would then swap the polarity of my jumpers to see the other column fed by that wire light.  I did this for all column wires.  Not only did this confirm all the connections were good, It allowed me to double check that each LED was installed correctly in it’s socket.  Here’s a couple of photo’s showing the test setup and a column lit during a test.

alt Test setup alt Column lit during test

I then separated the 17 conductors in the ribbon cable on each end, stripped and tinned the wires and attached them to the marquee wires starting with row zero thru 4 then column 0 thru 11.  I then wire tied everything in place.

alt Finished Marquee

Then came the moment of truth…   SUCCESS!!!

alt Success!

Even setup python on the pc so I could send my own messages…

alt Time sent from python

I hope this has been helpful to anyone attempting this project on your own.

I will warn you, this is a very time consuming project.  Be prepared to spend several hours soldering.  However, the reward seeing it running is worth the effort!!


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