Review: Logitech Cordless Presenter on Linux.
Date: February 2007.
I've been watching some of the videos from LCA2007, and I like how some of the speakers made their presentations smoother, and avoided being tied to standing next to their computer, by using remote slide-changing gizmos. It wouldn't help for my GIMP presentations, since those are usually live demos, but I do give other types of talks.
I didn't find much on the web about remote presenter support on Linux. Of course, the marketing literature all assumes you're using MS PowerPoint on Windows (or possibly Mac). I tend to write my slides in HTML, with navigation written in JavaScript, and present them using Firefox. How would a remote presenter work with a setup like this?
I did have some optimism: most of the presenters claim to need no extra driver on Windows or Mac, suggesting that they might use the USB HID protocol and show up as a standard keyboard or mouse. But what events do they send when you press buttons? The literature never says, but from what I could glean, each one is a little different. Some send Page Up/Down, some send Arrow Up/Down, some send left/right mouse clicks. As usual with hardware, the only way to find out for sure is to buy one and plug it in.
So that's what I did. I chose the Logitech, though it was a bit more expensive than some, because in addition to the forward/backward buttons and a built-in laser pointer, it also offered a built-in countdown timer with vibrator. I didn't consider the more expensive models which include a built-in mouse: I can't imagine an "air mouse" being accurate enough to be useful to me, and more buttons means more chances to press the wrong one during a presentation.
I'm happy to report that the Logitech works just fine under Linux. It runs off two AAA batteries (another detail that's hard to find out from the web -- some models use mercury coin batteries but none of the Logitech literature specified battery type) and includes a tiny USB spud that hides in a slot in the presenter when not in use. Plug the spud into the computer's USB dock, turn the presenter on (it vibrates to let you know it's alive), wait a while then press the laser button (it doesn't seem to send anything until the laser has been pressed at least once), and it shows up magically as a keyboard under X. (I'm running Ubuntu Edgy -- haven't tried it under any earlier distros yet.)
What does it send?
| Logitech button | X11 key |
|---|---|
| Left | Page Up |
| Right | Page Down |
| Blank screen | . (ascii dot) |
| F5/esc | F5 or Esc |
| Volume +/- | Nothing |
I never did figure out what controlled when it sent F5 vs. when it sent escape. It seems to alternate between them. Maybe this makes sense somehow when you're using Powerpoint.
Changing my navigation.js to handle Page Up and Page Down was easy, and while I was at it I added some code to make "." blacken the screen, and to go to the beginning on either F5 or Esc. Too bad about those volume buttons on the side not sending anything that javascript can see; maybe they send something like those "multimedia keys" at the top of some keyboards, in which case it might be possible to read them with some clever setkeycodes(8) hackery.
The countdown timer isn't quite as useful as I had hoped. It can only count intervals of five minutes, and you have to set it at the start of the talk (each button press adds another five minutes, and it starts counting down right away), which makes it great for those hour-plus talks but touchy for a 5-minute lightning talk or Toastmasters talk. It's still better than no timer, but there's room for improvement.
And the packaging is awful. It's the worst case of overly aggressive plastic packaging I've seen yet, requiring a determined attack with knife or heavy duty scissors (and a strong hand, RSI suffers should find a friend to help out). The mangled package I tossed into the recycle bin at the end weighed more than the presenter itself, including batteries. When will companies come around and go back to using simple eco- and purchaser-friendly cardboard?
Still, the unit works great, and I very much enjoyed being able to walk around during the one presentation I've made with it. I'm pleased.