User Manual

Connecting with Jumper Wires

Ribbon cables and their corresponding headers are sometimes a topological puzzle. Here’s a trick to help keep track…

If you hold the ribbon cable flat — no folds — and with both connectors facing you, keys pointed the same direction —

now there is a 1:1 correlation between the pins. The top-right pin on one plug links to the top-right on the other plug,

and so forth. This holds true even if the cable has a doubled-over strain relief. As long as the keys point the same way

and the plugs face the same way, pins are in the same positions at both ends.

Plugged into a socket on the LED matrix, one header now faces

away

from you. If you double the cable back on itself

(not a twist, but a fold)…to access a specific pin on the socket, the left and right columns are now mirrored (rows are in

the same order — the red stripe provides a point of reference). You’re looking “up” into the plug rather than “down”

into the socket.

For example, R1 (the top-left pin on the INPUT socket) appears at the top-

right

of the exposed plug. You can jam a wire

jumper in that hole to a corresponding pin on the Arduino…