Digital signage Campus USI
Addressable LED signage
Abstract
This installation consists of five identical aluminum frames with each 1740 individually addressable RGBW LEDs (reg, green, blue, and white channels) for a total of 8700 LEDs.
The installation has been commissioned by the Università della Svizzera Italiana (USI), and it has been designed and curated by Gysin & Vanetti.
My tasks consisted of engineering it both structurally and electronically.
Datas
year
2021
scope
freelance
commissioned by
client
process
Any of the 8700 LEDs can be individually controlled Front view Side view Side view Front side of one frame Back side of one frame The main structural parts consist of the laser cutter aluminum "stars" to which the aluminum profiles and the electronics boards are attached The back side of the center The central connection
Mechanical construction
The structure was based on 2x2cm aluminum profiles. The junctions were made with custom laser-cutted aluminum "star" elements with M4 threads to which the aluminum profiles were screwed.
A 3D-printed spacer printed in ABS flame retardant material at every junction allows the cables to be routed. On top of it, the four layers PCBs distribute the power and properly connect the various LED stripe's serial Data signals.
Multiple junction PCBs with castellated holes connect the LED stripes and the distribution PCBs for more straightforward soldering.
The project was parametrically designed in Fusion 360 for fast modifications and iterations.
In the following video, all the described elements are shown.
Electronics
The current required for the 1740 RGBW LEDs is quite considerable once fully lit. Four-layer PCBs were chosen to reduce the resistance for the current and were designed to connect all the LEDs stripes data lines.
Additional internal cables were added to the central PCB from the top connector for the same reason.
The main controller was a single Teensy 4.1 (incredibly fast in managing a myriad of LEDs). A Raspberry Pi provided wifi connection capabilities for remote programming for the Teensy.
A custom shield PCB was designed to connect the Raspberry Pi to the Teensy 4.1 and connect all the data lines to the LED frames via Ethernet cables (the most reliable, cheap, simple to install, and, most crucial, shielded solution).
The shield has also a buffer chip to convert the Teensy 3.3V data lines to 5V for the LEDs.
All the custom 4 layer PCBs designed for the structure A detailed look at one of the PCB; from the simple schematics, the layout is defined and routed accordingly. Vias connect the four different copper layers The Raspberry Pi and Teensy shield PCB featuring an Ethernet cable connection for each LED frame The shiled with all the soldered components The central connection The main top connection to witch the data and power cables are connected An edge connection A middle connection A side connection
skills
- 3D modeling
- Electronics
- EDA