Wiring a long chain of LEDs common lead

[StudentSA]

Good Day,

I am attempting to create a LED display board with 5mm LEDs and "pegboard". I have 48 LEDs in each row and 27 columns. Rows are to be wired common anode; and columns are to be wired common cathode thus creating the multiplexing grid.

Has anyone got suggestions on how to solder this setup?

I have tried running a single strand of CAT5 cable along the length of a row and "melting" the plastic shielding at the required spots but this does not work well as the plastic does not completely "evaporate" and leaves residues that make soldering a pain.

I have also tried enamel wire from a old transformer with limited success, resorting to using a metal file at the lead points to remove enough enamel to solder to.

Anyone know of an easier way? using bare wire vertically and horizontally is bound to cause issues.

Regards,
StudentSA

 

[djsfantasi]

Have you seen a construction article for an LED cube? Each layer is soldered together as your grid without insulation.

If you are still unconvinced that it can be done. On either rows or columns, after soldering each LED, slip on a piece of heat shrink tubing over the bare wire, cut to fit your spacing. Shrinking it is optional

 

[StudentSA]

I have seen and constructed a LED cube. Difference is that the LEDs for the cube are located within the lead length distance from each other.
In my present case the LEDs are spaced further than the lead length from each other and are all on the same level i.e. it is not differentiated on height.

 

[djsfantasi]

No, but only one layer of LEDs are at the same level. And you can replace the leads between LEDs with a bare wire or a straight length of copper. Insulate these connecting segments with heat shrink and Pow - you are set

 

[Ian Rogers]

A quick method would be to use foam sponge from the packaging of new equipment.... one layer down first with all the legs popping though.. solder all the rows... Then another layer then solder and then solder all the columns.. This way they will be insulated from each other..

 

[prof328]

I’m missing the point, why do you want to use one length of wire for each row and column.

As you are going to solder the joints anyway and the led legs will be bent in different directions why not just use ordinary multi strand hook up wire cut to short lengths and solder them at the legs of the leds.

Ok so you have two wire ends to solder to each leg, and with 1296 leds that’s a lot of joints, but the spacing is uniform and you could cut, strip and tin the ends of the wires beforehand, once done the attaching to the led legs would be quick and easy just tedious as there are so many.

 

[StudentSA]

Thank you Mr Rogers, I did not think of that, I could use a layer of some insulation, maybe even wax-wrap or cling-wrap.

prof328... yes I could cut all the lengths as spacing is even, that would require 1296 lengths for the vertical connects and a further 1296 for the horizontal. For me that sounds rough.

So what one length of wire would do is save on the snip,strip,tin setup time.

Here is some pictures of HALF the display.
The PegBoard:

The 2 Rows of LEDs populated:

The close up of enamel wire common anode:

 

[prprog]

StudentSA.

You can also consider using copper tape to "make" connections. You can create the trace needed.
Of course soldering is very easy. Once you have everything solder, then you can paint the copper tape.



PRPROG

 

[StudentSA]

Thank you all for the suggestions,

Just to wrap up the conversation, I ended up using bare single core wire (Ethernet wire, used a blade to shave off the plastic). Once soldered to the LEDs I used...

"Peel off nail polish" to "insulate" the sections between the LEDs. Took me only a few mins to wire, solder and paint a row of LED's.

Regards,
StudentSA