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This is the A-head

Part II: More Hacking Techniques

Repeat this for each of the 144 LEDs. After soldering each LED and before
sealing it, you may want to test your handiwork. Use a multi-meter to
measure either resistance, or set it to the diode test position. Touch the red
probe to the wire connected to the long LED leg and the black probe to the
wire mesh. If everything is soldered correctly, the LED should light up a
little when the meter is set to the Diode measurement mode.

5. Install a light diffuser over the LEDs

The LEDs are very strong point light sources. Since the LEDs are spaced
out on the wire mesh, it may be hard to see a clear image of the animation
being displayed. To overcome this, you may want to install some sort of
light diffuser in front of the LEDs.

One way to do this is to place a white cloth sheet or frosted plastic shower
curtain in front of the LEDs. The sheet will need to be spaced away from the
LEDs if you want to make the light from the LEDs look like large pixels. This
can be accomplished by building a frame out of PVC pipe to hold the sheet
and wire mesh in place, as shown in

Figure 8-7

. I will leave it to you to design

this simple assembly if you decide you need it.

Alternatively, you can add a small light diffuser on each LED. Low-cost Ping-
Pong balls are an option. Cut a small hole in the back of each ball and mount
them over each LED.

You can also omit the diffuser altogether and just show the bare LEDs.

PVC pipe frame

Frosted light diffuser

LEDs on wire mesh

Figure 8-7: LED diffuser