Current Projects:
Pinball Project
CNC Router
PIC Computer
LED Sign 2003

SigArch Sign Version 2

In 1998 or so, SigArchers decided to revive the old ACM sign that had graced the walls of our hallowed computer science building only a few years before. Instead of using a Motorola 68HC11 microcontroller, however, they would use programmable logic in the form of Xilinx FPGAs.

The completed sign had 2100 LEDs in a 100x21 grid, came with 8K of Cypress dual-ported SRAM, and two Xilinx 4005-series FPGAs. The entire circuit was wire-wrapped onto a large board and hung in the ACM office. Instead of having custom logic to render text, the new sign acts as a dumb framebuffer connected to the PC parallel port, allowing complete computer control of what's displayed. This was extended with a Java application to allow remote control of the sign via the Internet.

Sign applications have included:

• Date and Time
• Slashdot Headlines
• Conway's Game of Life
• Winamp Visualizations
• Email Display
• Power Glove-controlled Pong

An ongoing project has been to connect the sign directly to the Internet using an AMD Net186 evaluation board. This project involves writing a 16-bit, real-mode TCP/IP stack as well as a web server.