Laser Pointer Tracker System was an old project proposed and executed by John Hu 4 years ago.

It was a software-based human computer interaction device. It could detect the laser pointers by computer built-in camera. It used computer vision to locate the position of laser pointers in camera and coverted them to computer coordinate system.

The first example was to control a power point presentation with a laser pointer and gestures. This example is made with Win32 API and our owned gesture detections.

The second example was made by Flex. It is an interactive system, multile-touches photo gallery, and google map:

A Complex Thing: Keyboard Event?

Have you checked the keyCode for keyDown, keyPress, and keyUp events of browsers? The values of them are different. Some of them are ASCII code and some of them are printable key code, what?! We can find the detailed rules here. we can check this to know more about JavaScript keyboard event

It would be nice to have a page to test it. John Hu had created one for this purpose. Since the modern browsers will repeat the keyDown and keyPress, this page prints keyDown and keyPress while you hold the keys.



Since I used Lubuntu for Banana Pi, the compiling procedure is similar to cubieboard. We can download the source from node.js and do the configure and make. But there is one thing different. We have to configure with an extra argument, otherwise we get the segmentation fault:

./configure --without-snapshot
Lego Case for Banana Pi

My kids and I made a case for Banana Pi. No instructions but a lot of images:

Lego Case for Banana Pi
Lego Case for Banana Pi
Lego Case for Banana Pi
Lego Case for Banana Pi
Lego Case for Banana Pi
Lego Case for Banana Pi

Others can be found at my flickr account:

Banana Pi

I got a Banana Pi. But I havn’t booted it up because of lacking of a free sdcard.

If you guys interest in it, please find more information at

It has an IR receiver(I think), sata port, more cpu, and more memory in compare to Raspberry Pi.