I haven’t written here in a while, but that definitely doesn’t mean I haven’t been doing anything.
After considering the pros and cons, I’ve decided to not make a compliant surface, but to go with lasers instead. The big advantage is obviously that it’s a fairly cheap solution, and that I’ll have a zero touch interface. The downside is that the IR led’s that are in there now are pretty much useless, except to maybe fill in some potential dead spots. I’m going to leave the LED’s in for now, maybe I will take them out later. If not, I’ll be the first to build a hybrid FTIR – laser LCD multitouch (which is, for the most part, a pretty useless kind of hybrid).
Here is a picture of the laser I used for my first test today. It’s a simple laser leveler with a visible red laser, so perfect for testing.
It came with a tripod, which was nice since it saved me a lot of time setting the whole thing up.
Here’s a video of what the test looked like:
Remember; this is just a test. I’m using only one laser, so if my fingers cross the same line on the screen, the last finger won’t show up since the first finger is blocking all the light. For this reason I’ll have to get a second laser, so that all fingers will be illuminated at all times.
Also, you might have noticed that the blobs seem a little “choppy”. That’s because my wiring is actually sticking out about the acrylic a little bit, so when aligning the laser to the acrylic, the wires sometimes get in the way, blocking the laser. Another good reason to remove the LED’s and wiring, I guess.
Here’s a picture of the crappy wiring:
Anyways, this system appears to be working perfectly. Zero touch and dragging work great, and the lens is creating a perfect line:
I also ran a test using the stem of a wineglass as a lens; it does work pretty well, although the line is a little thicker and not as consistent. I think it would still work for this specific purpose though.
For my table I’m going to need IR lasers rather than visible ones. At first I considered taking apart a DVD burner and taking the IR diode from that, so I could build it into the laser leveler I got. Upon further investigation I found out that it’s cheaper to order the lasers and the lenses online, so those are currently being shipped to me.
I also finally ordered my LCD screen; I should have it by upcoming Wednesday, upon which I’ll have to perform some major surgery on it. I can’t deny that I’m a little bit nervous about that. This is the screen I got:
It’s a BenQ FP222Wa 22″ inch screen, really not much else to say about it. It’s pretty cheap to order online, and I know from experience that it’s a very nice screen, and according to the list I found it doesn’t have any FCC issues, so it should work fine for my table.
And last but not least, I finally bought some wood to start constructing the frame. I’ll being doing that upcoming Wednesday and Thursday, so stay tuned for more.
