Pupil Geometry

I’ve been trying to reduce the number of free variables in the mapping between the position of the pupil in a eye-camera image and the point of gaze on a screen, given the head location of a person. Previously I was just fitting an ellipse to the pupil and using the location of its centre. This method did not use all of the information I’d just obtained about the ellipse. In this post I explore one theoretical method of using the ellipse parameters.

Continue reading

Eye Tracking – The Eye Camera

Photo of a camera lens in an eye

In this post I’ll be describing how I made a head mounted IR camera for tracking where a person is looking. I’ve been working on getting low-cost home brew eye tracking running on my Mac. I want the computer to know where I’m looking on the screen and to be able to interact with my gaze. My first attempt uses a head mounted IR camera to determine the pupil position and a second remote camera to detect the head position relative to the screen.

Picture Rachel Chapman.
Continue reading

How to switch tablet input between multiple monitors on a Mac

A Wacom Bamboo tabletQuickly switch your tablet input between multiple monitors using some simple Applescript – no programming required. All you need to do is download the free app bundle below and then assign them to the hardware keys on your tablet. This quick switching allows you to use your full tablet for each of your monitors rather than dividing your tablet space between displays.

Read on to make the most of your tablet in a multi-monitor set up.

Continue reading

How to join loc-line modular adjustable hose without a special tool

Loc-line segmented adjustable hose

In this post I describe a simple way to join sections of loc-line hose with just a bit of wire. Loc-line make an amazing product. It is a hose composed of short sections connecting with ball and socket joints. The hose can be bent into the shape you need and it will stay there. It is great for making your own gorillapod for example. Connecting the sections with your bare hands is very hard so Loc-line sell a special tool for joining the sections. But you don’t need to buy that – read on and use my easy wire method instead.

Continue reading

Linking a domain to a website – Part 2 Finding the DNS

In part 1 of this guide I described what a DNS was and how to set it up for GoDaddy hosting. In this part, I’ll show you how to check that you have the right DNS names and how to set them with your domain registrar.

Finding and checking the names of the name servers

Getting the name of the name server right is important. If you choose the wrong name servers no-one will be able to see your site. Changing name servers takes some time to process, during which time your site may be inaccessible.  If you are transferring a live site you probably want to minimise down time and can’t afford to make a mistake or find the right name servers by trial and error.

Continue reading

Linking a domain to a website – Part 1 Setting up the DNS

Linking a domain registered with one company to a website hosted by a different company can seem complicated. There are several options to consider – frame forwarding, transferring the domain and changing the DNS servers. I think that changing the DNS is often the best option, but it can seem complicated.

In this post I introduce the domain name server (DNS) and what you need to set up. In the next part I’ll describe how to check that you know the address for the right DNS before you make the switch.

Continue reading

Kiva Wedding Gifts

I am not a big fan of having too much stuff. So when I got married earlier this year we decided that we did not want to ask our friends and family for gifts. However, it turned out that people felt very strongly that they wanted to give us stuff. My wife found a great compromise which allowed us to help entrepreneurs in the developing world grow their businesses and achieve economic stability by providing micro-loans.

Continue reading