Simple Lighting Effect With Led Panels

The simple, humble LED panes scattered around our house tell us the time, the weather, the train schedules, and when to expect the kids back from school. However, they help transform our house into something sinister for a couple of days every October.

The typical LED panel we use for displays is 32 rows of 64 columns. On average, we use two to four panels for a display. So:

32 X 64 = 2048 LEDs,

2048 X 2 = 4096 LEDs

2048 X 4 = 8192 leds.

That is EIGHT THOUSAND ONE HUNDRED NINETY TWO LEDs. That is a lot of light. Because we can control the color of each LED, we can match the color to almost any condition. The displays can talk to each other because we have a microcontroller or a microprocessor (Raspberry Pi, in this case).

This instructable describes two effects out of a dozen we have tried. In addition to what is described here, they can simulate the flashes of a lightning storm, the light of a genital fireplace light, or the light of a TV in a dark room. We hope you will find some inspiration for your ideas here.

A Raspberry Pi. We have used Pi3 and Pi4 for this project.

An Adafrut RGB Matrix bonnet or Adafruit RGB Matrix Hat

A power supply adequately sized for the number of panels used.

A frame such as found in one of our earlier instructables.

Years ago, I saw the film Heavy Metal for the first time. The film used the metaphor of a room glowing green to tie its various vignettes together and track progress through the story. ( Can you say Loc-Nar?) Okay, it was an animated feature ( cartoon ), but it was still an excellent effect.

Over the years, several attempts have been made to create the effect. Light bulbs could never quite get the color right. Early LED experiments using discreet components were expensive. Neopixels were very close, but the strips were hard to work with. Enter the LED panel.

The first time I visited Disneyland, I was eleven. I was fascinated with the rides and their effects, so I spent a lot of time in the library reading about them. One thing that struck me was the simplicity of some of them. I was fascinated by how they did the burning village scene in Pirates of the Caribbean.

https://www.instructables.com/Flaming-Windows/

To set up the effect, you need:

1. The LED panel
2. A white backdrop. This can be a white sheet, a white tarp, a white tablecloth, etc. It should be larger than the window or whatever area you are trying to use as a frame.
3. A fan. We have had the best luck with a box fan but have also used muffin fans or circular oscillating fans.
4. A method to support the backdrop

Look at the window you are going to use for the effect. Does it have a curtain rod? Will the rod support your backdrop while the backdrop is billowing?

Adding a fan to a Raspberry Pi or Arduino is easy. Adafruit sells a Controllable Four Outlet Power Relay Module, or you can read our instructions on making your own.

The brackets used can be found:

8020 series ten 45-degree offset beam for fan mount Thingiverse Printables

8020 Fan Mount for 120 mm Standard width Thingiverse Printables

The code used in this project is dependent on Henner Zeller's rpi-rgb-led-matrix library. Some samples of our code are provided below.

Okay, we are going to call this a little bonus content. Every single reviewer asked about it. ( Yes, I am using old video. )

The effect is super simple. It is based on an old Adafruit project. Animated Snake Eyes Bonnet for Raspberry Pi

I used it modified for https://www.thingiverse.com/thing:3177147, but looking at notes on using the software gave us an idea.

The big window eyes are done by taking the output from the HDMI port on the Raspberry Pi and running it to an HDMI splitter. Each output is run to a TV monitor placed in the windows. The black levels of the monitors are turned down so that the monitors become invisible in a dark room. Set the monitors back from the window to prevent reflections on the glass. We also use two slightly different-sized monitors placed at different distances from the window to give forced perspective depth to the eyes.

When we talk about using LED panels, the discussion of correctly powering the panels comes up. You can read about it and find some references in one of our older instructables: Simple-Extruded-Aluminum-Frame-for-LED-Panels or at /hzeller/rpi-rgb-led-matrix/blob/master/wiring.md

If you want to waste a minute and forty-two seconds of your life, watch the video. It shows the worst-case current draw on a single P3 32x64 panel. The data sheet recommends 5A for a reason. A number of our projects use four or more panels.

All of the examples in this instructable use a Raspberry Pi and an Adafruit Pi-hat or bonnet or an Adafruit MatrixPortal.

Full disclosure: This was originally written a couple of years ago. While the setup for the effects is the same, today, we use a series of Adafruit Matrix portals to accomplish the same effects. They do not require knowledge of UNIX to set up and operate the system.