Modding the stylus on a tc1100 tablet PC

May 8, 2006 5:42 AM

I have a HP Compaq Tablet PC TC1100 that I have bought for work purposes, I would like to hack the pen, so I can make it smaller, and mountable on a Bluetooth wireless scanner that is used in conjunction with the tablet.

How does this magic pen work? Its pressure sensitive, but you don't have to be touching the screen, so just any stylus won't work. I have spare tips for the stylus, but they are no good without whatever is in the barrel of the pen.
I plan on buying a spare pen and taking it apart, but I am hoping to go into this armed with any information I can get for you guys on here first.
Is it even likely that there is enough wasted space in the barrel that I will be able to get its sized down enough to do what I want?

posted by JonnyRotten to computers & internet (6 comments total)

Typically, battery-free pens like the one you have contain a coil and a small printed circuit board (PCB). The coil is excited (powered on) by the radio field emitted from the screen of your device. At least, this is how it works with Wacom tablets.

My guess is that you'll be able to make it marginally smaller, but you'll have to deal with the PCB, which is going to be flat, probably run the length of the barrel, and be rather delicate. So you might be able to shrink it in one axis and end up with an oval instead of a circle shape.

Also keep in mind, unless you want to lose pressure sensitivity, you'll need to support the mechanical part of that system- all the little springs and such that operate the pen nib.
posted by fake at 6:05 AM on May 8, 2006

The tc1100 is indeed based upon the Wacom system.

Their press release is here



With this being stated as how they work.

How Penabled pens work

A Wacom Penabled pen operates without batteries or wires by taking advantage of patented technology developed by Wacom in which an electromagnetic signal is sent from a sensor board to a pen and returned for position analysis, pressure sensitivity and other information. The Penabled pen therefore needs no batteries. It also has the ability to ’hover,’ allowing the pen to move the cursor without actually touching the LCD screen.
posted by Ostrich at 7:13 AM on May 8, 2006

fwiw, I've taken a look inside the one we have for the TC1000 and there's not a whole lot of room in there. (that said, the stylus for that machine requires a battery. but the circuit board spanned the diameter of the stylus so there's not a whole lot you can cut out of it.)
posted by mrg at 7:35 AM on May 8, 2006

I was planning to mod my own tablet-PC pen (for an M275), so I bought spares and took one apart. Here is a photo of the insides. This pen has no eraser on the back end, is one-button, and is for tablet-PCs based on a Wacom digitiser. I didn't find the time to build a new exterior for it, but hopefully the pic will be helpful.

My pen exterior is close to as narrow as could fit the guts, but longer. So if your guts are the same, you could easily make the pen shorter, but not all that much room left for making it thinner.
posted by -harlequin- at 9:48 AM on May 8, 2006

I'd also add that you could probably pretty easily shorten it further by snapping that circuit board in half, just above the switch button, and putting the halves side by side, then soldering wires to reconnect the traces. (Some circuits this would not work, due to multi-layer circuit boards, or low tolerance for trace capacitance, but I doubt any of those issues would crop up here).
posted by -harlequin- at 9:51 AM on May 8, 2006

You know, because this board is a sensitive radio circuit, snapping the board in half and resoldering may cause it to cease functioning properly. But if you have a sacrificial pen it might be worth trying.
posted by fake at 11:07 AM on May 8, 2006