A DIY Vacuum Pickup Tool

A cheap DIY vacuum pickup tool, helpful for SMD assembly.

Martin Oldfield, 24 Jun 2013

ADT74x0 temperature sensing

Analog Devices make some nice I²C temperature sensors, including the ADT7420 which is accurate to 0.25̣̣°C. Here’s a user space client for them.

Martin Oldfield, 10 Jun 2013

Watchdog

Watchdog: automatically do things when files change.

Martin Oldfield, 05 Jun 2013

Etch to lenny upgrades on Xen

I have a bunch of virtual Debian machines on a Xen box. When they were installed I used etch, but I've just moved one domU to lenny: here's my crib sheet. I suspect it won't be generally useful.

Martin Oldfield, 05 Jun 2013

Faking geocaches in Garmin GPX files

Garmin GPS receivers have a special mode to handle geocaches, but it's not been clear to me how the gadget decides which waypoints are geocaches. These brief notes describe something which works for me.

Martin Oldfield, 05 Jun 2013

A Turning Tetrahedron

The tetrahedron's a simple solid, but its moment of inertia isn't in the usual tables, so I thought I'd calculate it. There are two calculations here: one's straightforward but long, the other's short and cunning.

Martin Oldfield, 05 Jun 2013

Haskell qua calculator

Although Haskell is a fine language for hard-core programming, it’s increasing my tool of choice for trivial arithmetic too.

Martin Oldfield, 05 Jun 2013

Raspberry Pi GPIO cable

A useful cable to connect the GPIO port to a breadboard.

Martin Oldfield, 05 Jun 2013

The Bus Pirate on MacOS

Self-help notes on using the bus pirate on MacOS—mainly links to other documentation.

Martin Oldfield, 05 Jun 2013

Church Numerals

Fun and games with Church numerals in Haskell.

Martin Oldfield, 05 Jun 2013

Moments of Inertia

Some basic facts about the moment of inertia

Martin Oldfield, 05 Jun 2013

Places to eat in the Lake District

Some brief notes on places to eat in the Lake District taken on a trip in September 2008.

Martin Oldfield, 05 Jun 2013

Filtering GPS tracks

In practice I find that the tracklogs stored by my Garmin GPS receiver are quite noisy. gpsbabel easily filters the data, but having forgotten the relevant rules once, I thought I'd document them here.

Martin Oldfield, 05 Jun 2013

Time Machine hassles

One of my Macs recently died and I wanted to recover data from a Time Machine. Sadly this wasn't entirely trivial.

Martin Oldfield, 05 Jun 2013

TCP-IP v4.16 and Olimex flash

An easy way to patch recent versions (e.g. 4.16) of the Microchip PIC TCP-IP stack to work with the Atmel flash EEPROMs on Olimex boards.

Martin Oldfield, 05 Jun 2013

A Coordinate Decoder

A simple PIC-based coordinate decoder for geocache puzzles.

Martin Oldfield, 05 Jun 2013

The TTi TF930 and MacOS

Brief notes on reading data from a TTi TF930 3GHz counter from MacOS.

Martin Oldfield, 05 Jun 2013

The AArduino

Although the Arduino is very convenient, I wanted to build my own from parts you can buy from RS or Farnell. Rather than cloning the Arduino, I took the opportunity to make some changes: I removed the USB/Serial interface because I've got a ICSP programmer, but added crude support for dual AA battery support. The AA cells suggest a good name: the AArduino!

Martin Oldfield, 05 Jun 2013

Linux WiFi configuration

Aidés-memoires for configuring WiFi on a Raspberry Pi.

Martin Oldfield, 05 Jun 2013

Replacing a Logitech Mouse Button

How to fix a dodgy button on a Logitech mouse: the key was finding a replacement for the Omron D2FC-F-7N.

Martin Oldfield, 05 Jun 2013

Unicode games with perl, MySQL, and XML

Not for the first time I wasted a few hours getting Unicode things to 'just work' in a Perl project which mixed XML and MySQL. Hopefully these notes will prevent another repetition.

Martin Oldfield, 05 Jun 2013

Post the First

The first article

Martin Oldfield, 05 Jun 2013

Time-lapse photography

Brief notes on making time-lapse movies with a DSLR camera.

Martin Oldfield, 05 Jun 2013

ADSL modem rebooting

Controlling things over Ethernet, here a hung ADSL modem, with the PIC Mini Web from Olimex. This is more of a brief sketch, to test the blogging software, than anything too deep or insightful.

Martin Oldfield, 05 Jun 2013

A Toy Language Model

I wanted a toy language model so that I could write software which would identify the language of text.

The motivation for this is simple: given a list of geocaches, which ones have descriptions which I can understand!

Martin Oldfield, 05 Jun 2013

Finding Geocaches in English

A short program to find caches which are described in English. Very handy when caching abroad!

Martin Oldfield, 05 Jun 2013

A Spinning Sphere

Calculating the moment of inertia of sphere. Overlong in itself, but hopefully a fine preliminary to the related calculation for a tetrahedron.

Martin Oldfield, 05 Jun 2013

MacOS X and the Olimex AVR-ISP500

How to make the Olimex AVR-ISP500 work on MacOS 10.5.6: install version 1.005 of the firmware.

Martin Oldfield, 05 Jun 2013

Apple Cake

A recipe for apple cake.

Martin Oldfield, 05 Jun 2013

Perl tools for MPFS2

Recent versions of Microchip's TCP/IP stack (after version 4.11) use a new filing system and web server: MPFS2 and HTTP2. Microchip supply a Windows program, MPFS2.exe to manage things, but this is quite inconvenient for people on Linux or OS X. These Perl programs try to help.

Martin Oldfield, 05 Jun 2013

Starch Free Tiramisu

At a recent dinner party, one of my guests couldn't eat starch. This didn't seem compatible with my desire to serve tiramisu, but happily the lure of creamy coffee proved enough of an inspiration to find a solution: instead of coffee soaked sponge use coffee jelly.

Martin Oldfield, 05 Jun 2013

Perl and Xcode 4

I just bought a new Mac and installed Xcode 4 on it. However, I couldn't build any Perl modules with XS (bits of C) in them. Here's a solution!

Martin Oldfield, 05 Jun 2013

Places to eat and drink in Copenhagen

Some brief notes on places to eat and drink in Copenhagen.

Martin Oldfield, 05 Jun 2013

Stripboard Templates

A simple Perl script to generate blank stripboard templates.

Martin Oldfield, 05 Jun 2013

Getting an ARM toolchain on MacOS 10.6

I'm starting to play with ARM microcontrollers, and building a toolchain is a necessary step. Here's a log of my experiences.

Martin Oldfield, 05 Jun 2013