mt screen project

day 20

Success! Only pictures can explain...

day 19

Long time no post. Not really, it's only been 4 or so days. I've been gone for some of that so progress has been slow. The good thing is that it is nearing completion. As proof, here is a screenshot and a youtube video below. Ambient light seems to be working great. I've even played around using a paintbrush on the surface and got good results. Placing my phone on the table shows 4 dots at the corners, so it might be possible to recognize it later. I'm hoping to get a projector within the next few days so that the table will appear somewhat finished.

day 15

More changes! So instead of trying to flood the screen with light from my LEDs and block out the unwanted ambient light from the surrounding room, why not let that same ambient light power the screen? It only takes an extra step or two in the visual processing of the captured image, but it is much easier to do and allows for a wider range of lighting conditions. After setting it up today, I got the entire screen to work flawlessly. It is zero-force and can be set to react when an object comes within about 3mm. This means you could use something as light as a paint brush on the screen.

Again, no pics. There isn't much different with the box now, so I'll try to have some screenshots later.

day 14

Diffused Illumination is the way to go. FTIR just isn't giving me the reliable results I want. A quick test with only 8 poorly aligned LEDs for DI showed decent results already. Luckily for me, I just need to pull the LEDs from the screen and place them below it without doing any rewiring. Once I get the projector and screen things will start to come together.

No pics, just a revelation.

day 13

It's Monday so that means it's back to work. I made a list of 7 or so things to get done today and tomorrow and ended up doing all but 2 today. So let's see... Today I did some touchup painting, wired the fans and tested them, cut out a door from one side, added hinges, put on the top panels and painted them, and sorted out what the silicone rubber surface will be. The two things I did not do were to put the door on the box and test the screen more. I could not attach the door because it is too big and the tool I need is gone until tonight. I yanked and broke off 2 of the LEDs by accident and didn't want to solder it back so screen testing will happen later.

In all, a productive day. Looking ahead I think things will start to take shape soon.

day 12

I've been on a brief vacation for the weekend so I obviously have not done any of the project. It's Sunday so I'll be back to work tomorrow, but it is good to have some extra time to plan the rest of it. I've got some more tests to do with the screen, as the power supply was still giving me issues Friday. In the unlikely event that FTIR doesn't work out well, my backup plan is to use Diffused Illumination, which would be easy to implement using the current LED configuration. I've got a mental list of things that need to be done soon so I'm going to keep thinking about it.

And now, to give you a sense of how much I'm enjoying my weekend off...

day 10

It's Friday and I'm 20 minutes from leaving for the weekend. I just finished drilling the 3.5" holes for the 4 fans. Going by the few bruises I have just received, I would make a guess that you are supposed to use a drill press and not a hand drill for 3.5" bits. Oh well. Fans are in place now so that's nice. I'm still having issues with the $5 power supply, so I have switched it temporarily with an old 400W power supply I had. I'm also working on adding a door in one of the smaller sides of the box.

No pics today, you all will have just believe me. I swear it's all true. Really.

day 08

Went out today to get the wood pieces that will cover the top edges of the screen as well as some primer and black paint. I got the primer on and let that dry and then put the first coat of black paint on. I think after another coat or 2 it will look very nice. I also added two support pieces near the bottom and stuck the wheels to those so it now rolls away from me in our slightly ramped garage. I didn't drill the fan holes yet because I couldn't find the right drill piece. I'll probably do that tomorrow.

day 07

Getting the wood yesterday was quite a job in itself, so I waited until today to cut it and put it together. This also turned out to be a little tough, but I got it done. The screen can now rest upon a 24"x18" and 3' high table and boy does it look nice. It will look even better once it gets painted gloss black. Tomorrow will be for adding wheels to the bottom and drilling the 3" fan holes near the top. Since the idea is to have a computer and projector inside the box, good airflow is crucial. The fans will suck air in at the top and allow it to move down and out the bottom.

day 05

This weekend I spent a good amount of time on the project as I wanted to make sure I could get the LEDs out of the way. The power supply is giving out 11.2V instead of 12V, so I had to do a little redesigning and put the LEDs in groups of 9 and 8 instead of 10. 80 LEDs needed to be bent, glued into holes, soldered together, then have wires added. Now that that's out of the way, I just need to do a couple wire connections before going out to get wood for the frame.

day 02

Budget was approved today so I went shopping. Aside from the hurricane-like rain/wind, things went well. I went accross town to an electronics store to get some supplies, seen in the pictures below. I was drilling holes in the edges of the acrylic with a clearance of maybe 0.00005mm. Not really, but it felt that way. I finally finished that and called it a day. Tomorrow will be for testing each LED and finding a way to set them in the holes I drilled.

day 00

Time to start recording what I'm doing. As the <title> suggests, I'm working on a multitouch screen similar to the one seen here. There have already been screens built by students and companies, but as far as I know, no company is selling screens that use the same technology. Microsoft has been developing something similar, but they cost upwards of $10,000 and won't hit consumers for a while. There are also no hard-set instructions for how to build one. This leaves people to experiment to find what works for them.

I have recently built a prototype screen and presented it to the people I work for and they have agreed to fund the construction of a full-working model. Here at day 00, I am waiting for the budget request to go through so I can start shopping. I leave this update with an image of my desk after a few weeks struggling to produce a working prototype.