#411 cordwood-three

Custom build of the Boldport Club Cordwood Puzzle III, Project #25, May 2018, with an archway layout and a spring-loaded LED trigger machanism.

Build

Here’s a quick demo of the build on a custom test jig “LED Blinky Machine”..

Notes

This is the third Boldport Club project in the Cordwood series. See my build of the first and second. Here they are all together:

cordwood_series

The Kit

The kit arrrived in the familar brown paper

kit_arrival

kit_parts

If you want to build this kit, the easiest way is to join the club and order the BoldportClub kit. But you could do it without the kit: the PCB design is open source so it is relatively easy to make an identical (or similar) set of boards, and the parts are relatively easy to obtain:

Qty	Original Part	Mouser Equivalent
x6	220Ω 2W resistor, Multicomp MCF 2W 220R	603-RSF2WSJR-52-220R
x6	10KΩ 2W resistor, Multicomp MCF 2W 10K	588-OY-10K-E
x6	MOSFET n-channel transistor, Fairchild 2N7000_D26Z	512-2N7000
x1	1µF ceramic capacitor, AVX SA305E105MARC	80-C440C105Z5U-TR
x6	10mm green LEDs, Kingbright L-813GD	696-SSLLX100133SGD
x1	25mm M3 female-female standoff, ETTINGER 05.03.251	761-M1272-3005-SS
x1	25mm M3 female-male standoff, ETTINGER 05.13.251	761-M2120-3005-SS
x2	M3 screws, DURATOOL M38 CSSTMCZ100-
x1	10-pin 2.54mm header, Multicomp MC34739	710-61301011121
x5	6cm of 20AWG wire

Schematic

The circuit is similar to the other cordword projects: essentially an array of LEDs with low-side NFET switches. By default, the LEDs are on with a pull-up resistor on the MOSFET gates. The gate is exposed via pin header so it can be pulled low (turning off the LED).

Schematic

Construction

The conventional construction is a vertical stack. The Boldport guide outlines the construction:

I played around for a bit looking for alternatives, and settled upon an archway style which I found quite appealing;-)

build-side

So that’s working fine - I can toggle the LEDs by pulling any of the 6 gate pins low.

build-powered

Here are my working notes for re-arranging the connections…

custom_layout

A Custom Test Jig - LED Trigger Machine

So without getting too fancy, I wanted a nicer way of mounting and testing the project. One thing lead to another, and soon I had a completely pointless LED blinking machine: