just some thoughts about software and other things I like

Overview

Earlier this year (2016) while on a plane just after boarding, I noticed the ground crew all receiving their most valuable information via this massive LED matrix display. I was immediately interested in this.

Here is the awful photo I took of the LED display:

I took the photo to remind myself. I didn't need a reminder because I became immediately obsessed with the LED display technology and decided I needed to build a display of my own.

Besides the fact that it's just an awesome looking huge ass LED display, I find the display control and rendering software an exciting challenge. A kind of IoT display for mission critical data.

In terms of this specific display I thought:

  • how do they control that thing?
  • how much power does it use?
  • how do they render content to the display
  • what kind of subsystems are working together to get data like that on the display?

Why are certain display technologies suitable in particular environments? Sometimes your average LCD TV is perfect, provided you have a way to display your data. Some situations, like outside on an airport tarmac, require display technology viewable at larger distances or when visibility is low.

Some Examples

The data I'm talking about is often the answer one of these questions:

  • When is my bus arriving?
  • Did my flight leave?
  • What truck is at loading dock 5?
  • What are our portfolios stock prices?
  • What are the movie times?
  • Do we need to refuel the aircraft?

I started to see these types of displays everywhere, I walk by this one everyday in NYC:

It's nearby a bus stop, which clearly has many lines. There are typically a dozen or so people at this particular bus stop everyday. They all rely on this LED matrix display showing them when they can expect their bus to arrive.

You'll notice the LEDs appear off in a sort of diagonal pattern, this will come up later when when we work on the refresh rate and brightness of the display. Our eyes can barely detect the refresh rate, which is about 1/16th of a second. 1/16th of a second (or 16Hz) is somewhat slow when you consider the optimal 60Hz.

Why?

So why even work on something like this in the first place?!

Great question! I'm just interested in this and have been wanting to build something with these LED matrix display panels for some time. I don't have a great reason why besides my interest in hardware and writing software.


Next: Building the frame

Parts and directions for building the display frame from lengths of aluminum extrusion and M3 screws