November
2005, Issue 184
Large-Scale
Electronic Display
GOING
WIRELESS
I
used point-to-point wiring to build the motherboard
on veroboard. Each digit has a small board attached
to its back that carries the diodes and two RJ-45 (eight-pin)
female sockets. Seven segment signals (A through G)
and the Reset signal are brought in and daisy chained
out to the next digit via these sockets.
I
should have used a sturdier cable and socket combination
because RJ-45 and the matching cable aren’t designed
for these power levels. So far, however, they’ve held
up.
The
digit select signals are carried to each digit via hook-up
wire (see Figure 5). Because I mounted the motherboard
in a central position behind the scoreboard, the longest
run is approximately 5".
|
|
| Figure
5—Study the connections between the motherboard
and digets. Commands are sent from a laptop via
the serial port. |
I
also built a larger scoreboard containing 35 12' digits
that has worked well for the past two years. That board
is now mounted on the roof of an outdoor cricket stadium.
I encourage you to build your own system. Depending
on your needs, you may be able to use smaller, more
affordable digits. Incorporating a wireless connection
would enable the scorekeeper to sit even farther away
from your scoreboard. Next in the pipeline for me is
a wireless modular LED version of this system.
