soft-led-curtain-video-wall-for-stage-backdrop-at-special-events-stage-lighting-marketing-tours-entertainment-exhibits-corporate-events-live-show-fashion-show-nightclub-and-trade-show-12966

LED Walls, Cubes and Curtains

Preamble

A good friend of mine from the Riddim Shack, Koh Chang was after an eye-catching display for his mobile tuk-tuk bar now based in Sihanoukville, Cambodia. He wanted it to stand out from the crowd and be noticeable from a distance. I immediately proposed an LED wall, or curtain, that could be controlled by an Arduino based controller. This would open up a range of possibilities, rather than just a static display of lights. For example, in-bar advertising, an LED spectrum analyser display in beat with the music, videos, images, not to mention just random visual effects. The resolution does not have to be excessive, as it is surprising how forgiving the eye is on moving images, the ear is a much more strict master. Glitches in audio tracks make one wince, but video corruption is not a biggy. In fact, this is why in the olden days, when System 7 was cutting edge, Apple’s QuickTime gave priority to the audio track, and let drop outs occur on the video, if processing power was momentarily outstripped.

The visual side of things

In order to illustrate, I found some examples on the youtube web thing: LED Curtain is being used as DJ BOOTH ,which is very popular .By E-mail:marketing@huasun-tech.com

3D LED RGB Cube Laying Screen Display H48 Dance

Designs and calculations

Some very rough brainstorms, designs, and ramblings, can be found on github.

Other points of note

LED Labs

An interesting, and certainly eye catching, LED prototype board produced by LED Labs.

LED Lab

LED Lab Introduction and Tutorials

Using the versatile iOS app, L.E.D. Lab, one can create custom effects to run on RGB LED strip display. Most impressive.

Pin reduction via CharliePlexing

Reducing the number of pins required can be achieved using a form of multiplexing known as CharliePlexing. The following video from EEEnthusiast explains the concept

The wikipedia page explains more. Basically the number of LEDs that you can control increases exponentially as you throw in extra pins.

CharliePlexing table
CharliePlexing table

So, n(n-1) LEDs can be controller using n pins. In addition up to n − 1 LEDs sharing a common positive or negative path can be lit in parallel.

In these configurations, the relocated resistors make it possible to light multiple LEDs at the same time row-by-row, instead of requiring that they be lit individually. The row current capacity could be boosted by an NPN emitter follower instead of the typically much weaker I/O pin.

It should be noted that in the case of LED failure, then the effect on the rest of the LEDs in the matrix could be catastrophic.

Costs per type

Strip 5m/3cm at £8.08 or 50m for £70.44 = 166 LEDs (£2.40 for 50), or 1660 LEDs (£2.12 for 50) => 48.67, or £42.43 for 1000 LEDs => 6400 (80 x 80) LEDs @ £42.43 (50m) = £271.55, 4096 (64 x 64) LEDs = £173.79

Matrix = £2.60 each / (8 x 8) = £0.04 each LED => £40.62 for 1000 LEDs => £26 for 10 matrices wide, £260 for 80×80 display, £166.40 for 64 x 64.

Single 1.68 for 50 LEDs  => £33.60 for 1000 => 6400 (80 x 80) LEDs = £215.04, 4096 (64 x 64) LEDs = £137.62

Cheapest RGB Matrix Controller: RGB Matrix LED Screen Module Driver Board Full-color 8×8 Arduino(No Dot Matrix), for £7.07. Well pricey, costing more than the LED matrix itself.

RGB LED Matrix Controller
RGB LED Matrix Controller

LED Cube does the Harlem Shake!

 

Of interest

From Multiple rgb leds

If your RGB LEDs are WS2812-style, 5050-size units, it is no problem to control dozens of them using an Arduino Uno or several other models of Arduinos. [For ATtiny systems, other libraries than Adafruit’s NeoPixel may be needed; the NeoPixel library keeps several bytes of state data per pixel, which some other libs don’t.]

WS2812-style LEDs typically are arranged in serial strings, driven by a single IO pin from an Arduino.

If you have more than half a dozen WS2812s in the string, power for them should come from an external power supply, rather than via an Arduino’s built-in 5V regulator.

For more information, see related questions like Arduino with WS2812 using Adafruit NeoPixel library fade in/out different patterns, and Arduino and WS2812 RGB LED Strip “freezing”, andfading colors on a ws2812 strip; also see Google search Arduino Stackexchange for WS2812.

 

If all you want is some lighting effects, then I’d suggest some LED strips with controller and remote control from one of the well-known e-stores. You can get a power-supply, remote control and RGB LEDs at a reasonable cost. For 24 LEDs, you’ll need a separate power supply anyway; the Arduino isn’t enough. If what you want to do is learn about Arduino, I’d recommend jwpat7’s advice. Try to get some Ws2812b RGB LEDs on a strip, and a power supply, and experiment with Adafruit’s NeoPixel library

 

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