This is the A-head
161
Chapter 8, How to Hack a Building-Size Display
The 50-pin connector labeled J2 in
Exhibit D
connects to one of the 50-pin
connectors on the ISA card. The wires from J2 are in turn connected to P1,
a common DB25 connector. This cable from J2 to P1 should be kept short.
It is intended to bring the relay drive signals from the connectors inside the
PC to just outside the PC. P1 is in turn plugged into P2, which splits the
drive signals. All six of these cables are shown in
Figure 8-13
.
Solder groups of three relay driver boards together, as shown in
Figure 8-
14
. You will notice that each relay board and individual driver is labeled
and that the wire bundle is held firmly in place with hot-melt glue and tie
wraps. This makes the wiring easier to manage and incorrect wiring easier
to troubleshoot.
After connecting each group of three relay driver boards to the control PC
either using the interface board or by soldering the relay drivers directly to
the PC control signals, it should look something like
Figure 8-15
.
P1
J2
25 connec
tor cable
P2
J3
J4
J5
J2
J2
J2
J1
J1
J1
P1
J2
25 connec
tor cable
P2
J3
J4
J5
J2
J2
J2
J1
J1
J1
P1
J2
25 connec
tor cable
P2
J3
J4
J5
J2
J2
J2
J1
J1
J1
P1
J2
25 connec
tor cable
P2
J3
J4
J5
J2
J2
J2
J1
J1
J1
P1
J2
25 connec
tor cable
P2
J3
J4
J5
J2
J2
J2
J1
J1
J1
P1
J2
25 connec
tor cable
P2
J3
J4
J5
J2
J2
J2
J1
J1
J1
ISA parallel card inside PC
Exhibit
D
Exhibit
C
Figure 8-13: ***NEED CAPTION****
Figure 8-14:
Three relay driver boards
New figure and paragraph added.
Figure 8-15:
Complete system setup