Cordwood Puzzle 1

Cordwood Puzzle 1


Attention ;)
This project is now available at Pimoroni! Click
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A modern take on an old assembly method

In the 1950s and 1960s inventive engineers saved space by using the 'cordwood' assembly, where components were sandwiched in between two circuits boards. This construction became less useful with reduced component sizes, PCB manufacturing advancements, more compact integration, and surface mount technology, but is still a lovely piece of history. Combining both old and new, the Cordwood Puzzle is a tribute to this construction and to the engineers who came up with it.

The puzzle is to correctly assemble the circuit with the components at hand. Once completed, all LEDs light up when power is applied. When connected to a controller board each LED can be individually controlled.

Unfortunately(!), all the comprehensive assembly guides were mysteriously missing from the kits.

Cordwood Puzzle 1 was project #3 of the Boldport Club.

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What’s included

  • 2x red 10mm LEDs 1168543

  • 2x green 10mm LEDs 1142474

  • 2x yellow 10mm LEDs 1168543

  • 6x nMOS FET, Fairchild, 2N7000

  • 1x 2-pin SMD 2.54mm pitch header

  • 1x 6-pin SMD 2.54mm pitch header

  • 6x 10KΩ 2W resistors, 1602193

  • 6x 150Ω 2W resistors, 9338101

  • 1x 1uF capacitor, 1547799

  • 2x 24.5 mm M3 standoffs

  • 4x 8mm long M3 screws

  • A bit of 0.84mm diameter 20AWG hookup wire

  • 2x identical PCBs (96.6x16.6 mm each)

Saving space back in the day | source


Challenge yourself by assembling the kit without further instruction. Before you do that, however, note the following: When connecting to a board, make sure that the I/Os can tolerate the voltage levels that are applied to the Cordwood! Also, make sure that you do not short power and ground!

Additional information

Community contributions for this project

Open source circuit board design files