Update on LiveScribe Pen
I spent 2 hours tonight reading the press releases for LiveScribe, a pen that writes on plain paper, but also can record your pen movements and audio in realtime, allowing you to playback meeting notes. I read tech reviews, press documents, a new york times review, and 20 odd support forum posts. Here are my impressions:

First of all, this is not the first time this idea has come around. There are already plenty of "digital ink" pens on the market. You can classify these pens into two major categories: echo-location based and microdot based.

Echo-location based pens require a small piece of hardware placed at the top of your writing surface. As your pen-tip rolls across the page, this hardware senses those vibrations and uses the time difference to calculate where you're writing on the page. These pens can store a digital representation of your writing on any surface, but they require the extra echo-locator to be placed at the top of your surface. Theoretically, if you're writing on a surface with a different speed of sound, these pens will also have problems tracking your position.

Micro-dot based pens use a small camera to track your pen's position as it types. The camera is usually located underneath the pen tip, and it reads microscopic dots printed on special pieces of paper. From what I've been able to read, these pens offer better resolution than echo-location pens, but they require special paper that is usually quite pricey.

The LiveScribe is a microdot pen with some interesting twists: it embeds an LED screen, a processor, a speaker, and a microphone into the pen's body, all under half an inch diameter. The microphone in particular makes it possible to record audio while you are taking notes and revisit those notes later. The processor and the LED screen allow you to use portions of the paper as "applications." For example, all their notebooks come with a printed out "scientific calculator", which allows you to type in numbers with the pen tip and display the answer on the LED screen. Another example application is a photo-printout of a piano keyboard which allows you to play music through the pen's speaker. They've also released an alpha SDK for writing new applications for the pen, based on Eclipse and Java.

Unfortunately, the pen has many downsides right now:
- The company is brand new. The pen only started shipping one month ago in June, Investing in a pen now incurs all the early adopter risks. In particular, the company seems to keep delaying their release dates for new features. There was much grumbling about this in the forum, though lately the company has belatedly been coming through on it's promises.
- The micro-dot paper is expensive, and some of the notebooks are low quality. They have been promising since before April 2008 that users would be able to print their own paper "soon." The latest estimate I was able to find for this feature was the end of 2008. If you can't print your own paper, your pen becomes a $200 Bic if the company goes out of business.
- The pen isn't the best pen for writing. I've seen posts requesting gel-tip pen refills, posts about what foamy tubes make the pen easier to hold, and complaints from customers that the pen is too large for them to hold. The pen comes with no cap, so people recommend getting a big sharpie marker cap and stretching it out.
- Right now, the software only runs on Windows, though they promise that a Mac port is coming shortly. Linux kernel hackers have been posting to the forums asking for technical details, but they've been ignored by the support team.

I have to say that I find this pen very attractive. Right now I carry around the following with me at all times--
- wallet
- keys, complete with usb key and leatherman scissors on a keychain
- my phone
- A pad of paper and a pencil, perfect for temporary notes.
- A digital voice recorder ($50)
- Occasionally an ipod

This pen would allow me to get rid of the voice recorder and free up pocket space.

Furthermore, I'm really intrigued by the capability of a "pencast". Most mathematicians learn math from whiteboards and frenzied explanations. In fact, I have learned more by watching a mathematician puzzle something out on a whiteboard than from any mathematical paper. The best math is always done on whiteboards with frenzied explanations, and I think a "pencast" has a much better chance of capturing these explanations than a stately LaTeX document.

Three things are keeping me from purchasing this pen right out:
- Finances are a bit tight with Dani and I right now. We aren't using our savings, but we aren't putting anything away either. Things will get better in a couple of months when both Dani and Kaylie have jobs and can help with the rent. Until that time comes, I can't justify a $200 toy.
- Before I buy this pen, I want to be able to produce my own microdot paper.
- Furthermore, the last thing I really need from a pen like this is the ability to print out pdfs, mark them up, and save my markup digitally. When reading math papers I often do the extra math the authors skip in the margins of the paper. Eventually I loose that markup and have to re-derive it. The whole process infuriates me, but the best way to do math is on a sheet of loose-leaf. Several other people have asked for this feature, so once they allow people to print their own paper I think this feature will shortly follow. 0