Control hardware devices with a Wacom Intuos4 and WaxBee

[roipoussiere]

Hello everybody,

For an artistic project I want to connect a Wacom tablet (I bought an Intuos4 for this purpose), to an Teensy (or Arduino or everything similar).

The goal is to control hardware devices (such as motors, etc) with the tablet.

So I would like to read from the tablet:
- pen position (X and Y);
- pen depth level;
- pen orientation;
- tablets buttons events;

I don't want to make a bridge to a computer through USB, which is the original purpose of the WaxBee project as I understand it.

Is this possible with the WaxBee project and can you give me a starting point or an appropriate documentation?

Thank you!

Roipoussiere

[Ertew]

1. What type of interface have Your tablet? After quick research I found that the most popular version of Intuos4 have USB interface, which is almost useless for You.
If You have tablet with RS232 or ADB interface You're fine.

2. https://github.com/popbee/waxbee
- Here are files for WaxBee converter. You need it for play with ADB interface. For RS232 interface You can build all You need using only information from below link, depend what 'language' speak Your tablet.
http://linuxwacom.sourceforge.net/wiki/index.php/Wacom_Protocol_Overview

[roipoussiere]

Thank you.

It's mini USB, like this: http://www.adventure-spec.com/media/catalog/product/cache/1/image/1800x/040ec09b1e35df139433887a97daa66f/m/i/mini-usb-connector_copy.jpg
And the model number is PTK-440.

Why is it almost useless?

Oh and I read the USB HID specifications and I found all parameters I need (position, pressure, orientation, etc.)
This means I can get them with for example the Arduino HID library (https://www.arduino.cc/en/Reference/HID)?

[Ertew]

In RS world exist only 2 lines. RX (listen) and TX (speak). You can connect any two devices and they will talk to each other. Devices may use different languages and understand only certain interface but at least they can notice 'hey, somebody talking to me'.

In USBw world You have host (master), device (slave) and single channel (bidirectional twisted pair). Host can command (transmission to device) or ask every 1ms (device reply - transmission to host). The problem is that You cannot connect two hosts or two devices together.

PC, RaspberryPI, some mobile devices and few development boards have USB host. Your tablet, Arduino, Teensy and a lot of other stuff have USB device.
The WaxBee converter read data from serial/ADB tablet and emulate USB tablet.
Yes, You can buy add-on board for Arduino that have USB host, but it's very expensive and complicated. So I never play with it.

Apart from that, there are at least two more solutions.
1. Get computer (rPi should do it).
2. Buy tablet with serial interface, like this one:
http://www.ebay.co.uk/itm/Wacom-Digitizer-II-UD-1212-R-12-RS-232-Serial-Interface-tablet-only-/201725222515?hash=item2ef7c29e73:g:e0IAAOSwj0NUcObw
or spare screen with digitizer from almost any tablet-PC like this one:
http://www.ebay.co.uk/itm/Fujitsu-T-lifebook-Wacom-Digitizer-drawing-Tablet-12-inch-Art-digital-paint-/252207720461?hash=item3ab8c0680d:m:mwTI6iHyrV5-V1R8vVPU5tg

[roipoussiere]

Thank you for your good explanation.

I think I prefer the USB shield solution:
- it's not so expensive (around $30 http://boutique.semageek.com/en/391-arduino-usb-host-shield-7640152110634.html) comparing tout a raspberry pi or a new tablet;
- and I want to control devices such as motors in real time, which is far easier with an Arduino than a computer (you need a realtime kernel for instance).

Now my main question is: in what language "speak" my tablet through USB? HID?

Is it the same language that speak the WaxBee converter ? (it's an important point, because in this case I am sure to be able to replace/upgrade my tablet by any tablet supported by WaxBee, with the converter )
In this case, where can I find the language specifications?

I found these intersting Arduino libraries:
- USB Host Shield library
- HID library

[Ertew]

Unfortunately each tablet may have different byte order in the USB frame. Plus Wacom tablets does not have any documentation, all knowledge comes from reverse-engineering.
WaBee is also build based on known devices. WaxBee can emulate any tablet, but out of the box have config files to emulate Intuos2 and Intuos5s. Your Intuos4 definitely have different ID and few extra bytes (buttons, etc) but main parts or communication frame should be the same for a lot of tablet models.

You should search for Linux tablet drivers. Source codes must contain information how to decode frames from many Wacom tablet. Arduino just need to mimic this.

[roipoussiere]

Ok, thank you, I will take a look on Linux drivers.

Just a last question, because I want to understand this black magic : in what language speak Waxbee to the computer?

[Ertew]

Wacom serial tablet get X, Y and pressure information, let say 14b resolution. Next, split that bits into few bytes and send to computer as complete frame.
Wacom USB tablet do almost the same things, just pack similar frame into USB frame with it's header, packet-length and checksum.

WaxBee try to speak exactly the same language as original USB tablet. The goal is to use the same Wacom drivers for USB tablets and for WaxBee.

[bernard]

Waxbee is the reverse of what you need. 

The easiest and more promising I think would be to get a linux-based system, run the standard wacom drivers and interface that with, say "Python" to do whatever pleases you. (no need to buy a costly Rasberry PI, there are other alternatives like the 9$ "C.H.I.P.")

https://www.nextthing.co/

Before buying check if you can find a solution to talk to your "motors" or other hardware devices.  These boards typically come with lots of GPIOs.