BackLight

During the summer, I was building my multitouch table out of an LCD screen. I took the back off the lcd screen (backlight and all) so I could place a camera below it to see my hand as I touched the LCD (LCD screens are transparent ). The problem was that the screen does not give off its own light so I had to make a light below (and below the camera 19in away)to shine through the LCD, and illuminate it.

But… Because the LCD is clear, when you looked through the screen you would see the individual  LED lights I used to light it up causing huge hot spots. This was a problem. Normally I would use a diffuser to fix this, but I needed the camera to have a clear view of the back of the LCD so I had to figure something else out. The main issue was that with a normal LCD when the screen is white, it is actually almost completely clear, so you where just seeing the backlight. In mine, you see the LED array, and the camera, and everything else in there. So I took some vellum and made a cone diffuser that went from the LCD screen to the camera. This allowed the LCD to have a complete diffused back light and allowed the camera to have a clear view as well.

Below the Diffuser I put my array of 192 LEDs. Works great, but it’s not as bright as I wanted. I just have to upgrade the lights. (they are already on their way.) I just have to wait till after my break (going to visit family) to work on it.

Back to work on FoodE <– Final for my service design class

Weekend Update

 This week left me with some extra time, though most of it went to seeing family for Thanksgiving, I did manage to create my first gesture-esk application for my multitouch table. When you place 3 or more fingers on the table, it looks for 3 that are making a triangle within a certain size, if it finds one it places a circle in the middle, symbolizing bringing up a menu system.

I’m not sure if there is a better way to do what I did (it seemed to contain too many for loops), but it starts at a finger, then looks for two other fingers within a certain distance from that one. If it does not find two others close enough, it moves to the next finger. If it finds two or more, it checks to see if any of them are within that distance from each-other, and stops if it does. It works really well, and thanks to a friend on a forum I visit, I was able to use an incenter equation to calculate the center.

I started thinking about the next push for RISDpedia. Im looking at ways to document electronic components next. One of the things I have been thinking about is how to document the availability of said components.

Because you cant just pop into a store to purchase them (sad I know), I needed to have a list of placed they can be ordered. As luck would have it octopart (if you don’t know it you really should) has a search API. Octopart lists all the place where you can order a part (Digikey, Mouser etc), if it is in stock, ho many they have, and more.

The API was a little hard to break into though, and it took me more than a few hours to get everything out of it I needed. It is only available as a JSON object and im not the best with javascript. I used MooTools to handle the JSON call, but because there is no print_r (as in php) to pull, and see everything out of an array, I had to do loop after loop to find the entire structure, so I could then map it out, go back, and just ask for the information I want.

Granted, I’m sure im doing it completely wrong, it works. At some point when I have time Ill make it into a MediaWiki extension for RISDpedia.