Monday, November 24, 2008

Some More Final Touches (VIDEO)

So I haven't posted in a bit since Ive been busy learning Flash/AS3 and balancing schoolwork. I am going to be transporting my MT box this weekend, so I wanted to finalize the top so that it didn't slide around anymore.

I put some nails through the side walls and acrylic that go into the removable top:

This keeps all the pieces from moving around and gives it a snug fit.

And here is the top, all screwed together and very strong:

The top part (the top bezel and the outer wood rails) lifts completely off so that the acrylic can be easily cleaned.

I also took the webcam and stuck it to the backlight with some double sided tape in a more permanent installation:

You'll notice it is my Microsoft VX-3000 webcam in there, not my PS3 Eye. I am still waiting on the PS3 Eye to be enabled to be used in the newer better tbeta software (windows).

The setup for now is going to stay as a Side DI LCD, since it's works pretty well, and I've turned my attention to writing some programs. I started with making a simple game of Tic Tac Toe, but after learning a bunch, got bored and moved onto something else. Currently I am writing an app which pops up a menu when you put three fingers down, creating a triangle of less than a certian number of pixel area. After last night of discovering the benifits of using the Point class, I made a bunch of headway.

Below is a video showing the basic build of the box and showing its functionality. Since my computer is slow (single core), and I am using the Microsoft VX-3000 webcam, which gets about 24fps or so, the Photo App runs a bit slow. Upon watching the video it is obvious that my calibration was a tad off also. Oh well, I still like how the video turned out :)

Saturday, November 8, 2008

Better LED Rails, FTIR Attempt

Earlier this week I ordered a piece of acrylic 12" x 24" x 1/4" from It is about 6mm thick, where my LEDs are 5mm in diameter. I also got a new laptop charger off of craigslist to run the LED rails. Here are the specs of the charger:

Since it is 19vts (19.43 volts so says my voltmeter), I needed longer chains of LEDs in series (12 instead of the previous 8), and higher ohm resistors (12 instead of 1), all according again to

Again, here are pics of my previous LED rails taken off:

And what the LCD looks like without any LED rails on it:

It's basically the LCD crystal taped to a piece of thin acrylic with both masking tape for securing it down, and electrical tape on top of that to create a solid black frame.

I went to Home Depot and got some aluminum L beams to mount the LEDs more accuratly in and cut them to size:

I measured out the height needed to drill the LEDs at on the beam:

And then drilled the rails, insulated them with electrical tape, put the LEDs in, soldered them together, along with wires running to the new power supply, and put the power supply into the case.

(That's the laptop power supply hiding behind the power strip in the corner)

And below in a Side DI setup, which is the same as FTIR, minus the acrylic:

Then I put some screws in the floor to hold the backlight in place:

I then began work on polishing the edges of the sides of the acrylic. I was told to get 800, 1000, and 2000 grit sandpaper and some polishing compound, but Im on a budget so I only got 800, 1500 and the polishing compound.

Initially I just hand sanded the edges, but the curve of my palm caused the edges to be curved instead of flat, so I wrapped the sandpaper around a deck of cards as a sanding block and that worked well. The edges came out a lot smoother.

Here is a video showing the initial performance of the FTIR setup:

It works okay, but I have to press harder than Id like to get the blobs to show up, so I posted to the nuigroup forum to try and get some answers on improving it. There also is very little capability of dragging, since applying pressure and dragging is hard to do.

What works really well is removing the piece of acrylic and using it again as a Side DI setup. The higher amount of LEDs and the more even distribution of them makes it for a perfect setup in Side DI. Also the height of when the blobs appear from a falling finger can be reduced to about 5mm, which is really good, but still not as good as a working FTIR setup, so the quest continues to find the best and most practical setup when on a budget and using an LCD.

Thursday, November 6, 2008

PS3 Eye Distance Test

So after I had previously taken my new PS3 Eye webcam apart and put in a piece of floppy disk to act as a IR filter, I downloaded the software from AlexP to let it run on my computer. Here is a test showing the camera placed under my screen:

The camera is elevated because I also tested the viewing angle of the lenses in both its clockwise and counterclockwise position (the lenses rotates to zoom in/out). The following diagram is roughly the formulas needed to calculate what size screen you can get from a certain depth:

(I had originally done a rough one in sharpie and the member noverflow on the nuigroup forum converted my info to the one above)