The Cordwood Puzzle returns! Boldport Club Project #13, May 2017
The original Cordwood Puzzle became an instant classic with club members, and the concept returns this year with a brand new puzzle. The cordwoods evoke an era of stuffing massive components into small spaces. This is real hardware!
As before, it really is a puzzle, so if you don’t want any spoilers - read no further.
Unboxing and Parts Count
|R2,4,6,8,10,12,14,16||10KΩ 2W resistor, Multicomp MCMF02WJJ103A10||8|
|R1,3,5,7,9,11,13,15||220Ω 2W resistor, Multicomp MCF 2W 220R||8|
|C1||1uF ceramic capacitor, AVX SA305E105MAR||1|
|Q1-8||n-channel MOSFET transistor, Fairchild 2N7000||8|
|10-pin through-hole header, Multicomp MC34739||1|
|10mm yellow LED, Kingbright L-813YD||4|
|10mm green LED, Kingbright L-813GD||4|
|25mm M3 standoff, ETTINGER 05.03.251||1|
|Piece of 0.84mm diameter 20AWG hookup wire||1|
The LEDs are rated for 20 mA with forward voltage of 2.V (yellow) and 2.2V (green). Therefore, with the current-limiting resistor of 220Ω, the maximum supply voltage is around 6.5V.
How It Works
Each LED is switched by a corresponding MOSFET. The MOSFET gate is pulled high by default with a 10kΩ resistor, so the defualt LED state is ON.
Each gate is also connected to a pin. If these are pulled to ground, the corresponding LED turns off.
With it’s twin, the original Cordwood..