So much to do, So much to see, So much more that give me the stress bees

Its Highlighted FYP Interview time!!!!! *Julian, Ben and Yuan Feng freak out*

We've come a long way since the last post. The screen is now working - That is, we can use it with demos and our own innovated Flash Application - and we've got a new projector, courtesy of the TSO-upstairs. THANKS!

We finally have a covered screen, thanks to Yuan Feng, and are now using tracing paper on the back of our screen for display purposes; it is opague enough to give us a display, but translucent enough to allow infra-red light to pass through.

We are now using a USB Web-Camera, for several reasons:
1. It's much easier to calibrate than a Wiimote, since we can actually see what we're pointing at.

2. It has a far higher sensitivity(The difference between USB and battery powered devices) compared to the Wii-mote, which increases our usable screen size five-fold.

3. We are able to use CCV(Community Core Vision) otherwise known as tbeta, an open source/cross-platform solution for computer vision and machine sensing, which allows us to track blobs of light and use them as cursors in Flash applications.

Now we have an innovated Flash application - a map, which is rotatable, scalable, and soon to be scrollable from level to level.

Look out for more on JBYFFYP!!

Hardware almost done

After a long time of deliberating, trial and error, and much argument and solder balls made, we finally have a working prototype of our screen. The specs of the screen are as follows:

45x45cm clear acrylic (which I sandpapered to test if it would aid in diffusing the light from the projector; we will replace the acrylic later on)
4x4x8 Infra-Red LEDs lining the screen
1.25V, 50mA per LED, connected in parallel
80cm distance from Wiimote to Screen
20.4cm distance from Wiimote to Groundzero
WiimoteTester (by Brian Peek) is the program we're using to test.
Mr Shiney Finger and Mr Silver Thumb are pieces of aluminium foil wrapped around a finger and thumb to reflect as much of the infra-red light as possible.



Our Multi-touch screen!



The red dot is from Mr Shiney Finger touching the screen and reflecting IR light into the wiimote

Update and pictures!

Today we got 20 new IR LEDs courtesy of Julian's ordering on the Online EEE store. Soldered 4 with a 220 Ohm resistor together and mounted them on a piece of aluminum and scotched taped that to the 2 acrylic boards taped together. The result was that the Infra Red light is actually able to cross the entire width of the board and still is relatively strong. However, it is still unclear whether the light is being refracted when we touch the screen, or if it is so weak that it seems like noise.


Benjamin posing with the IR Light shining through the width of the board.

Here are two videos of previous successful attempts to refract the IR light.

Limitations of IR LEDs

After being told that we can actually use handphone cameras to detect IR light, we tried it and found that with our current setup (IR lights aligned to the acrylic, but not shining into it using TIFR) the range of refracted light is very small, and even if we used LEDs all around the screen it would give us only a usable 10x10cm screen; not desirable.

We shall order more LEDs asap, and this coming week we will build some sort of stand for the screen, and begin to try different methods to use TIFR.

Problems found after testing

Tested with one of the 2 pieces of acrylic(it works with both pieces, but it is difficult for one person to hold it all together), and found that a screen is not necessary to refract the light; that is, any object that crosses the path of the IR light will bounce it toward the Wiimote, and it is detected as a tracking point.

Tested with paper alone. The IR LED is able to shine brightly enough through the paper to register on the Wiimote up to 30cm, but when refraction is tried it does not work at all.

Highest distance tested with paper and one piece of acrylic(should go higher with a proper setup and more than 2 hands): 30cm.

Voltage: 9v battery

Number of IR LEDs: 1

Problem: 1 IR LED on 9v only shines far enough to give about 5cm distance in one direction, with about 2 to 3cm to the side. i.e one LED only gives about 25 square cm of 'touchable' space at max. Not very usable for a large screen.

Improvements: Build a prototype setup for more stability and higher accuracy.
Find out the maximum distance the IR light can be refracted till, and which LED gives the highest distance. Also consider ways to power up setup distributing enough power to each IR LED to shine far enough.
Other possible materials: Frosted wallpaper, Tracing paper

Genesis

And the FYP Blog is BORN amidst Cheeseburgers and Mcspicy meals.

Have just gotten Wiimote and test acrylic board from Mr Teo. Yuan Feng will sand down an edge of the board. Other components with Benjamin (Wiimote, 4 Emitter LEDs, 4 220 ohm resistors). BTW Julian made this blog.

Happy Chinese New Year!!!!! Best wishes to our project too!!!!!