Next years Xmas Display - Page 1
Forum section: electronics / projects

author: Distinctly Average
author_rank: Contributor
timestamp: December 14, 2020, 12:56:53 am
content: This year to appease my daughter I built a window LED display. This was supposed to be able to display text and some basic animation but I screwed up. How? Well I ordered some WS2811 LED strips (30 LEDs/M from the bay of fleas and while they worked, they only had one chip per three LEDs instead of 1 per LED that were advertised. Wile the display works (a grid 30 LEDs/M of 18 wide * 24 LEDs controlled by a K-1000C) it is effectively 18*8 due to the way the LEDs are configured. It still looks good for some effects but not ideal.So the plan for next year is to use some WS2812b LEDs that are 150 LEDs/M. I reckon I will have enough to do 36 * 100 LEDs all individually addressable using a 2 port controller. No worries there.Wiring the firs lot up was a challenge. I stuck the strips to some square conduit, 1 at the top and on at the bottom. Along the top linked all the 12v inputs and all the GND inputs with loops of wire. Then wired the data line in a snake route top-bottom-bottom-top...... This took ages and isn't too tidy.So next year I was thinking of getting a couple of PCBs made up and sticking them to the conduit for strength. Would it be a bit insane to make a PCB 1240mm long by 15mm high for this project then soldering the strips top and bottom to that? I've never used or even seen PCBs of that kind of dimension? Of can you think of a better way of achieving this other than me going the whole lots of bits of wire route?

author: phil from seattle
author_rank: Super Contributor
timestamp: December 14, 2020, 01:41:15 am
content: Not sure you will find an inexpensive PCB house that has 1.2 m panels. Shipping might be tricky as well.But even if available, I would look to build modular panels that can be connected to form any length.Or, you could just use LED tape like NeoPixels. Their 60 pixels/meter tape might be close. There are tapes with more LEDs than that out there. It might even be possible to do for this XMas.

author: Distinctly Average
author_rank: Contributor
timestamp: December 14, 2020, 01:59:00 am
content: I am using tape but it is still a lot of soldering and looks untidy. Basically I have 18 strips of 24 leds. I plan to upgrade that to 32 strips of 100 LEDs. You have to join all the 12v/GND contacts at the top, and all the data lines top and bottom. That is quite a lot of solder joints and bits of link wire. It looks very messy.You are probably right on the size. Probably get away with a number of shorter PCBs. If I made them modular with connectors each end that would make them nice and flexible design wise.

author: phil from seattle
author_rank: Super Contributor
timestamp: December 14, 2020, 02:15:12 am
content: I was referring to the 3 leds joined together issue when talking about tape.If you have a router (manual, not CNC), you could make a tray to hold the tape with maybe 2 to 3mm deep dadoes. That would tidy the tape up quite a bit.

author: Distinctly Average
author_rank: Contributor
timestamp: December 14, 2020, 03:25:33 am
content: Turns out there are actually dedicated connectors for these that clip on. Still means lots of wire but at least they are clipped on so no soldering. I could possibly put the ends inside conduit to hide all the wiring.Good thought on the actual tape part, Making some dado as you suggest might work. This hangs in a window though so may eat up too much light.Maybe next year I could build it as a panel and fix it to an external wall. If I used two sheets of Perspex, the front one being opaque, I could then fit it to an external wall and the light would be diffused rather than points.