David Johnstone

Things I've made


Occasionally I create a single page to try something new and be creative. Sometimes they're even useful.

Tweet wall visualisation

Here's a visualisation for Twitter. Give it something to search for and it will show those tweets. It's very pretty.

Barnsley's fern on a HTML5 canvas

Barnsley's Fern on a HTML5 canvas. It's 180,000 green dots drawn using a simple formula, and it ends up looking quite nice.

Hash collision calculator

A tool to calculate the probability of a hash collision. It was meant to be a simple bit of code with lots of CSS to make it pretty, but that was before I started looking at JavaScript big number libraries…


David Johnstone's website


This is the website that you're looking at now. As you might be able to tell, this is where I keep a blog, make the occasional fancy web page, and might someday do a bit more.

Cycling performance analysis

Cycling Analytics

This is a website I'm building for serious cyclists to track their riding. It's the ideal intersection of web development, cycling and analytical goodness for me to be working on.

A searchable directory of Presbyterian churches in Australia

Find a Presbyterian Church

A directory of Presbyterian churches in Australia. Like most things I make, I can think of plenty of ways to improve this.

Note taking website


This is a note taking website that I created because I wanted to use it. I think it's really useful.

Hawthorn Presbyterian Church

Hawthorn Presbyterian Church

The website for my church.