### International Object Sizing Tool

I often take pictures of objects for this blog when I'm making stuff (such as the Cansole or Home-made 7x7 display) and one constant problem is scale. It's hard for people to know what size the objects are. For example, here's a small HD video camera that I'm planning to use on GAGA-2. This shot shows the camera with its insides out:

Tiny, but how small?

To solve the problem I've created the International Object Sizing Tool that can be photographed alongside an object to give an idea of scale. It has five different ways of showing the size of the object: three common coins, a credit card and centimeter and inch scales. Here it is:

The entire thing is credit card sized (itself an international standard) and I've included the Visa logo and a fake card number and name so that you can recognize it as a credit card sized object.

There's an inches scale on the left, a centimeters scale on the top and three correctly scaled coins: a one Euro, a US quarter and a British Pound.

I made the image in OmniGraffle and printed it out and then stuck it to the back of an old credit card (actually an old airline mileage card since it wasn't embossed) that I'd sanded down.

So, how small is that HD video camera?

If you want to make your own one of these, the PDF is here.

Anonymous said…
Useful. I like giving an indication of the size in the text as well, but you need to take care with the units. I once submitted a paper with a photo caption along the lines of " is 70cm along each edge, with a Euro coin shown for scale." Unfortunately, I meant 70 millimetres, and one of the reviewers came back with the comment "No wonder the British rejected the Euro - the change wouldn't fit in their pockets."
Pantaz said…
Nice. Thanks for sharing this.

I typically just use a ruler, or machinist's scale alongside what I'm photographing. Your card is probably better for quick visual impact.

One odd thing -- why is the 3cm hash mark bent/angled?

### Your last name contains invalid characters

My last name is "Graham-Cumming". But here's a typical form response when I enter it:

Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not. What they actually meant is: our web site will not accept that hyphen in your last name. But do they say that? No, of course not. They decide to shove in my face the claim that there's something wrong with my name.

There's nothing wrong with my name, just as there's nothing wrong with someone whose first name is Jean-Marie, or someone whose last name is O'Reilly.

What is wrong is that way this is being handled. If the system can't cope with non-letters and spaces it needs to say that. How about the following error message:

Our system is unable to process last names that contain non-letters, please replace them with spaces.

Don't blame me for having a last name that your system doesn't like, whose fault is that? Saying "Your last name …

### Importing an existing SSL key/certificate pair into a Java keystore

I'm writing this blog post in case anyone else has to Google that. In Java 6 keytool has been improved so that it now becomes possible to import an existing key and certificate (say one you generated outside of the Java world) into a keystore.

You need: Java 6 and openssl.

1. Suppose you have a certificate and key in PEM format. The key is named host.key and the certificate host.crt.

2. The first step is to convert them into a single PKCS12 file using the command: openssl pkcs12 -export -in host.crt -inkey host.key > host.p12. You will be asked for various passwords (the password to access the key (if set) and then the password for the PKCS12 file being created).

3. Then import the PKCS12 file into a keystore using the command: keytool -importkeystore -srckeystore host.p12 -destkeystore host.jks -srcstoretype pkcs12. You now have a keystore named host.jks containing the certificate/key you need.

For the sake of completeness here's the output of a full session I performe…

### More fun with toys: the Ikea LILLABO Train Set

As further proof of my unsuitability to be a child minder (see previous post) I found myself playing with an Ikea LILLABO 20-piece basic set train.

The train set has 16 pieces of track (12 curves, two straight pieces and a two part bridge) and 4 pieces of train. What I wondered was... how many possible looping train tracks can be made using all 16 pieces?

The answer is... 9. Here's a picture of the 9 different layouts.

The picture was generated using a little program written in Processing. The bridge is red, the straight pieces are green and the curves are blue or magenta depending on whether they are oriented clockwise or anticlockwise. The curved pieces can be oriented in either way.

To generate those layouts I wrote a small program which runs through all the possible layouts and determines which form a loop. The program eliminates duplicate layouts (such as those that are mirror images of each other).

It outputs a list of instructions for building loops. These instructions con…