[Micah Elizabeth Scott], aka [scanlime], has been playing around with USB drawing tablets, and got to the point that she wanted with the firmware — to reverse engineer, see what’s going on, and who knows what else. Wacom didn’t design the devices to be user-updateable, so there aren’t copies of the ROMs floating around the web, and the tablet’s microcontroller seems to be locked down to boot.
With the easy avenues turning up dead ends, that means building some custom hardware to get it done and making a very detailed video documenting the project (embedded below). If you’re interested in chip power glitching attacks, and if you don’t suffer from short attention span, watch it, it’s a phenomenal introduction.
Continue reading “Glitching USB Firmware for Fun”
A few years ago, Wacom, the company behind all those cool graphics tablets, teamed up with Samsung to create the S Pen, a rebirth of that weird pen computing thing that happened in the 90s and a very interesting peripheral if only someone would write some software for it. [Kerry D. Wong] was wondering how the S Pen worked and wired up some hardware to take a look at how the pen communicates with the phone.
It was already known that the S Pen was powered by an RF field, and works somewhat like RFID. Listening in on the communication would require a coil of some type, so [Kerry] disassembled a small speaker and connected it to a scope.
A look at the captured waveforms from the S Pen reveled the carrier frequency appears to be in the range of 550 to 560kHz, outside the range of standard RFID. He doesn’t have the equipment to decode the complete protocol, but a few things can be deduced – the screen senses the location of the pen by detecting a dip in the RF field strength. The only information that is transferred between the pen and phone is the 11-bit pressure sensitivity and a 1-bit value that signals the button is on or off.
[Kerry] put the waveform data up on his site should anyone want to make an attempt at decoding the protocol.
Years ago, [Greg] got a Wacom Artpad II graphics tablet through Freecycle. What’s the catch, you ask? The stylus was long gone. When he found out how expensive a direct replacement would be, the tablet was laid to rest in his spare parts box. Fast forward a few years to the era of the phone-tablet hybrid and [Greg]’s subsequent realization that some of them use Wacom stylii. Eight bucks later, he’s in business, except that the tablet is serial. Wacom no longer supports serial tablets, so he had to convert it to USB.
With the help of the WaxBee project and a Teensy 2.0, he would be able to emulate an Intuous2 tablet by sniffing and re-encoding the packets. Things got a little hairy when he went under the hood to remove the ADM202 TTL-to-RS232 chip with a Dremel—he accidentally gouged some of the pads it sat on as well as a few of the traces. Feeling frustrated, [Greg] took some high-res pictures of the board and posted them to a message board. As it turns out, those pictures helped him recreate the traces and get the tablet running. A little big of glue and tape later, he was in business. [Greg] even gave himself access to reprogram the Teensy.
Wacom, purveyors of fine pen tablets for digital artists, basically have two product lines of pen tablets. The first, Intuos, is a great pen tablet that give an artist the ability to turn a computer into a virtual dead tree notebook. The second product line, the Cintiq, takes the same technology and adds an LCD to the mix, effectively turning a drawing tablet into a second display. [Bumhee] wanted a Cintiq, but didn’t want to pay the Cintiq price, leading him to install a display in his old Intuos tablet. It’s an amazingly simple build, making us think we’ll be seeing a few derivatives of his work in the future.
The display [Bumhee] used for this modification is a Retina display from an iPad. With the right adapter, you can easily connect one of these displays to a computer, giving you a very thin 2048×1536 9.7″ display. The initial tests to see if this mod would work on his tablet – removing the metal shield on the display, placing it on the tablet, and drawing – were a success, giving [Bumhee] the confidence to irreparably modify his tablet.
From there, the modification was a simple matter of cutting up the enclosure of the tablet, installing the display with a few screws, and installing a piece of glass over the display. Very easy, and it’s just about the only way you’re going to get a pen tablet with a small, high-resolution display for less than a thousand dollars.
Thanks [David] for sending this one in.
[David Revoy] recently picked up a brand new Cintiq 21UX, and while he liked the drawing pad overall, he was less than impressed with the tablet’s buttons. He says that most 2D linux apps require a good bit of keyboard interaction, and the built-in buttons just were not cutting it.
After seeing a fellow artist use a joypad to augment his tablet, [David] thought that he might be able to do something similar, but he wanted to add a lot more buttons. He dug out an old Logitech game pad that was collecting dust, and disassembled it, rearranging some buttons in the process. Once he was happy with the layout, he built a cardboard enclosure for the PCB and hooked it up to the Wacom via USB.
He spent a few minutes mapping buttons to key presses using Qjoypad, and was up and running with an additional 14 buttons in short order. He says that the extra buttons make his job a ton easier, and add a little bit of comfort to his long drawing sessions. We like the fact that it is a non-permanent fixture, and that he was able to repurpose an old game pad in the process.
Check out the video below for a quick demonstration of his drawing pad hack.
[via Adafruit blog]
Continue reading “Adding extra buttons to a Cintiq drawing pad”
[Lesa Wright] just started selling enclosure kits used to convert a Wacom tabet into a Cintiq clone. You need to start with your own Wacom tablet, there are kits for four different models. You’ll also need to track down some other parts: a compatible laptop LCD screen, controller kit, and some cable extenders. From there, the kit takes over, with several pieces of laser-cut acrylic needing to be glued together properly, then a surprising number of spacers need to be cut from foam board in order to mount everything..
The kits come in at around $225. That might seem a bit steep since you need to bring your own electronics to the party, but have you checked out the price of the original Cintiq? You can expect to drop about twelve-hundred bones on a ready-to-use model. Before you take the dive, you should watch their collection of assembly videos, it’s quite a process.
Reader [Chad Essley] asked us:
“I’m wondering if the vast knowledge base of HackADay’ers out there might know of some way to turn almost any laptop into a touch screen of some kind. Actually, any surface.”
He has an older Wacom Tablet, and would like to be able to add resistive touch screen capabilities so that he isn’t forced to use the Wacom pen. Being an artist and part time hacker, he even summed up the question in a comic-style post.
Continue reading “Ask Hack a Day: Touch Screen Hack”