Xmas Lights Pixel Grid

Outside my home, facing the main road i have some railings, i decided to attach LED pixels to them to form a ‘pixel grid’. Think of it as an extremely low resolution LED TV. It should allow for some fancy patterns and even scrolling text.

So as usual the first thing to do is draft up some sort of design, so i came up with this..

Pixel Grid Design

So the total Pixel dimensions is 13 High x 48 Wide Giving a total of 624 Pixels.

Each pixel requires 3 data ‘channels’ (Red,Green,Blue) meaning a total of 1872 Data channels are needed. As the maximum limit of the ESPixel controllers is 512, I’ve divided the grid into 4, meaning each controller is configured for 156 Pixels (468 Channels).

The next step was to figure out how to power the LEDs and more importantly how to overcome the Voltage drop along the cables. As the strings are only 5V voltage drop is a big issue. I didn’t do any fancy calculations at this point. It was a simple case of ‘inject’ wherever reasonably possible. This is what you can see in the bottom right of the drawing. ‘Start’ is where the controller is connected, and the ‘pwr’s are the parts of the string that are also connected to the 5V supply.

Once i had it all designed, it was a simple case of cutting the strings up and soldering them all together. I had to add lengths of wire to allow them to reach from one column to another, and also add the extra wire in to ‘inject’ the power. All the connections were covered in adhesive lined heat shrink tubing to try and keep waterproof. This was a very boring process that took many hours.

 

After finishing that and giving them a test, the next job was to actually fit them all to the railings. This was another very tedious job that took many hours. Each Pixel is held on with two cable ties giving a total of 1248 cables ties that had to be fitted and trimmed.

If i do this again next year i will defiantly be making a some sort of bracket system or some other simple quick way to attach them. I got there eventually though, and i’m pretty impressed with how it turned out.

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