Research and Development

Promethean on Linux - Test Results

Promethean is traditional wallmounted interactive whiteboard. The model in our tests was pen controlled Activboard ABV378S300. Touch is recognised when the pen touches the board physically. The tested whiteboard didn't have loudspeakers, so we couldn't test how well they work with linux, but in our understanding there are such models available. The whiteboard looks nice and robust, the canvas feels also durable.

Promethean's pen resembles a normal ballpoint pen that has a single button attached. When the pen is moved within a couple of millimeters from the whiteboard, it is possible to move mouse cursor without pressing the left button. Other tested models didn't have this feature. Left mouse button is pressed when the pen touches the board. Tested model had two identical pens with it. In theory there is support for multitouch, but the tested whiteboard would need an update for it to work. So whether it works with linux couldn't be tested this time.

Promethean and Linux

We had tested Promethean some time ago and linux support has improved noticeably. Software packages for Ubuntu are distributed through an apt repository which makes installation and updates easy. Other vendors don't have their software available this way. For normal users this makes installation painfree. Software was translated in both Finnish and Swedish.

After installation Promethean ActivInspire works nicely and calibration can be started by pressing Promethean's logo on the whiteboard with the pen. This makes it easy to use the whiteboard without having to use mouse or keyboard. Also dualhead support works and calibration is easy to use in dualhead setup.

Latency is sometimes noticeable, but overall speed is good. The most annoying feature is the random cuts in touch recognition. Solid lines look often dashed lines if one doesn't really concentrate on pressing the pen properly. This might not be a big issue when one gets used to the whiteboard and pen. If one presses the pen wrongly it creates annoying sounds. We couldn't figure out if the sensitivity can be adjusted.

Even if installation is painfree in single computer installation, centrally managed environments cause various problems. Promethean requires a custom kernel module to work. When installed in LTSP fat client chroot, the running kernel is different from the kernel used in the fat clients. This makes the kernel modules installation to fail.

Other technical problems are file permissions and security problems caused by too relaxed permissions. There are more details in the end of the article. We have reported the finding to the developers, but we haven't yet heard back from them.

Overview

+ Pen can be used to move mouse cursor without simulating left mouse button at the same time
+ Packaging and apt repository
+ Easy to do tasks needing good precision
+ Dualhead support works nicely

- Requires a closed source kernel module to work
- Pen touch recognition cuts off randomly

Bugs

Here are technical problems found in the Promethean software:

  1. Activdriver package gives normal users a chance to become root while the package is being installed
  2. /etc/xdg/Promethean is globally writeable and license code and user settings are placed there. Some of the information should be put under user's home directory instead and /etc should be write protected.
  3. meta packages conflict each other, e.g. activ-meta-fi and activ-meta-sv cannot be installed at the same time, but still the language support can be used for multiple languages
  4. Could the software be made to work without a kernel module? Installing the kernel module fails now it the running kernel is different from the target kernel. If kernel module is absolutely necessary, it should install always correctly and not assume that the running kernel is the kernel that it should use.
 

-Antti Sokero (Technical work by Juha Erkkilä and Veli-Matti Lintu)

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