These steps are only required for the “talking computer” prop; skip ahead if building the “total conversion beam.”

Install Key Caps

Fit the 9 key caps onto the mechanical key switches by press fitting them over the stems.

Get the key plate ready to install the key switches. There are 9 corresponding square holes, one per switch, with the center one at an angle.

Install Switches to Key Plate

The key plate is symmetrical and doesn't matter which side the  switches are installed. If one face looks nicer than the other, make that the top. Press fit the switches into the square holes to install them into the key plate.

Installed Switches

Double check all of the switches are fully seated into the key plate. Orientation of the pins doesn't really matter but feel free to orient them similarly. 

Ground Wires

All 9 switches will share a common ground connection. 8 short wires were measured, tips stripped and tinned (apply a thin layer of molten solder).

Ground Wire Lengths: 1.25 in

If using silicone ribbon cable, you can cut off a single chunk, then peel it apart into 10 pieces. Only 8 are needed here, but save one of the spares, you can use it for the amplifier board later.

Cable for Key Switches

A longer ribbon cable is used to connect the opposite pins of each key switch. The ribbon cable features 10 wires, 9 for the signals and 1 for the common ground connection. Splay the wires at each end about 1/2", strip just a small amount and tin the ends.

10-wire ribbon cable length: 8 inches

If you already have a healthy assortment of wire and didn’t get the ribbon cable, that’s fine, you can do this with individual 8-inch wires. Bundle them up with some tape, a zip-tie or heat-shrink tube to reduce chaos.

Shared Common Ground

One short wire and one wire from the longer ribbon cable is soldered to a pin on one of the key switches. 

The pins on the switches have no specific polarity; it doesn't matter which pin these ground wires go to, as long as they reach.

Solder Grounds

Proceed to solder all of the short wires to the ground pins on each of the 9 key switches.

Solder Signal Wires

Proceed to solder all of the signal wires to the opposite (non-ground) pin on each of the 9 key switches, peeling apart a little more of the ribbon cable to make each wire reach.

This guide was first published on Nov 09, 2021. It was last updated on Apr 22, 2024.

This page (Keypad Assembly) was last updated on Mar 08, 2024.

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