As a mechanical engineer, I typically fill a 192-page notebook every six months with words and sketches. Just ink on dead trees. No easy way to digitize, backup, or search all that content. Numerous notetaking apps for the iPad attempt to provide me the solution for this, but none quite get there for one main reason: you can’t create precision sketches or tight handwriting with your finger or any of the iPad styli available. Your finger is too stubby to see exactly where a line will begin, and the stylus offerings have been almost exclusively fingertip shaped. The only stylus I have seen that is any different is the DAGi Stylus, which has a clear tip with a small dot that ostensibly shows the exact placement of the line. Reviews of that device indicate that the small dot doesn’t always match up with where the iPad thinks it is.
The iPen from Cregle, Inc. is a Kickstarter project that offers an alternative solution. Unlike the more common passive styli described above, this is an active stylus that uses a combination of data scanned by a receiver on the edge of the writing surface and the input of the tip on the touchscreen, it is able not only to provide output that is more reminiscent of a ball point pen, but also generates a handy (optional) cursor to show you where your tip will begin its stroke. The result is a drawing experience that can produce useful detailed sketches.
The other major problem with using a passive stylus is that resting the palm or heel of the hand on the touch screen registers touches that affect the input. The combination of infrared and ultrasonic signals from the iPen to the receiver locates the stylus tip while ignoring the capacitive reaction from incidental hand contact. If you prefer not to wear gloves when sketching, this is a pretty significant advantage.
There are devices that behave somewhat similar to this. I have tried the Wacom Inkling device, which uses a receiver at the edge of the paper to capture sketches drawn by a digital pen. It does a pretty nice job of re-creating all the details of the artwork. The iPen does not yet have pressure sensitivity like the Inkling, but that is a feature they claim will be incorporated in the next version. The Livescribe pen also captures handwriting and images, but only on specially marked paper. The magic bullet for Cregle would be to get their iPen refined enough to turn the iPad into a tablet as elegant and powerful at sketch capture as the Wacom Cintiq. I will be watching with hopeful anticipation.
As of this post, the only apps that currently support the iPen are Ghostwriter Notes, My Notebook!, iWriteWords, and GoodNotes, but several others are in development and should be ready by February of 2012, according to Cregle.