Ben North's blog.

Covering various topics, usually of a vaguely nerdy nature.

08 June 2014

A Simon-playing robot

My 7-year-old daughter and I built a robot which plays the memory game 'Simon'. Servos use string to pull 'fingers' made out of Lego, pressing the game's buttons. Phototransistors sense which lights are flashing, with an Arduino controlling everything. It successfully plays a complete game of Simon!

16 May 2014

Free Software collaboration at the National Library of Ireland

RTE recently carried a news piece announcing the release of a large volume of historical digital images by the National Library of Ireland. One detail in the piece caught my eye: it quoted the library's Digitisation Programme Manager Sara Smyth as saying Since 2010, we have overhauled our digitisation workflows and put in place key […]

20 January 2014

An original escapement design?

© Trustees of the British Museum[source page] On a recent visit to the British Museum in London, I was interested to see a very curious escapement mechanism in one of the clocks, a creation of Thomas Tompion in the 1670s. I am certainly no expert on clocks, but I had never seen an escapement where […]

27 November 2013

An oscillator from a jam-jar lid

Fiddling with a jam-jar lid suggested its tamper-evident pop-up button exhibited hysteresis, and so I did some experiments on a blackcurrant jam lid to test this. Adding weight 50g at a time, the lid flexes very slightly, but stays popped up with 800g on top. It pops down when you add 50g to make 850g. […]

22 September 2013

Debugging a Hot Wires circuit

Jude was given an electronics set for her birthday, called Hot Wires. You connect components together with poppers to make circuits, and it's generally very good. One of the experiments is called 'traffic lights', and is supposed to be a circuit where you choose whether a green light or a red light shines, by pressing […]

05 September 2013

A fruitful exchange with the State Examination Commission

While looking through some past and sample papers to help with some volunteer maths tutoring I do, I came across what I was fairly convinced were errors in a question in a sample paper written by the State Examination Commission. What followed was a very positive exchange of correspondence with the examiner, and the end […]

01 July 2013

A Lego escapement (and failed slow-motion)

I recently came across a post on the Makezine blog showing a video of a very pleasing mechanism, the MacDowall single-pin escapement. Zach and I recreated it as best we could, although we didn't go as good a job as the original when it came to a rigid support structure. Nevertheless, our copy worked: [Youtube] […]

29 June 2013

Cobra: a Dragon 32 game from my past

About thirty years ago, my dad and I wrote a game for our Dragon 32 home computer. It was originally a pen and paper game for two players; in our version you played against the computer. I have tried to recreate the experience on the web. It needed a bit more room than this blog […]

11 May 2013

Snakes and ladders: end-game rules

My 5-year-old son is mysteriously keen on a Snakes And Ladders game we have, but there is often some discussion about what the ending rule should be. The winner is definitely the person who lands on square 100 first, but what to do if you roll a number which would take you past square 100? There are […]

19 April 2013

Simulating a laser-based image projector

Some experiments to explore the ideas used by an image projector using the Fourier transform as its underlying mechanism.