The long awaited Multitouch Technologies book authored by members of NUI Group (http://www.nuigroup.com) has officially found it’s first release! As one of the co-authors of the book, I am proud to see a final initial version come to fruition. The book, which consolidates articles from the NUI Group Wiki, includes sections on how to build Multi-touch devices, multitouch software resources, a glossary of terms and more. I  believe, as the book develops further, this will be the best resource for multitouch information on both the web and in print.

If you’re unfamiliar with NUI Group, I suggest reading the about page http://nuigroup.com/log/about/. NUI Group is currently the single best resource for multitouch technology and hopefully will become the largest database for Natural User Interfaces and emerging technology. If you’re interested in do-it-yourself hardware/software, HCI, or multitouch interaction, NUI Group is the place to be.

If you like the book, leave some feedback below! If you’d like to contribute to future sections of the book, you can get involved here: http://nuicode.com/projects/wiki-book

Download the Book |  Submit Feedback |  Join the Discussion

After waiting about 20 hours and letting the silicone rubber cure overnight, I went ahead and “unmasked” the silicone to see how it curred. From the look of it, it cured quite nicely. It isn’t completely even as far as the whole thing being completely smooth and 1mm thick, but this really shouldn’t affect it’s performance. After further inspection, I found that there were no bubbles in the silicone! Bubbles are one of the main concerns when pouring silicone yourself. I think my success had to do with mixing the A and B parts for a good amount of time (12 minutes).

As you can see, for the most part it is pretty smooth. The parts on the right side look worse than they really are.

Again, it’s not as bad as it may appear. Remember, the whole thing is only 1mm thick, so those slight raises are only 1/2mm and can’t be seen when when looking straight on.

Now off to test the silicone! Check back for results.

Well, the silicone arrived today. It took 5 days from the time of ordering online. I’ve done a lot of research, talking to others that have poured silicone and watched a couple videos so I was prepared for what I needed to do.

The best video to date is from Blaxwan and it really provides great documentation and information on how to pour the silicone.

[youtube="http://youtube.com/watch?v=bnjeWbvVCCo"]

Here are a couple things not mentioned in the video that I would like to add:

1) Make sure that you read the directions carefully on the package.

2) Measure out the portions of A and B by weight (not volume) with a gram scale. The main reason most people don’t get the silicone rubber layer right the first time is due to the A/B ratio being incorrect.

3) Be patient, but work fast. Although this particular silicone doesn’t fully set for an hour, it does start to set in about 30 minutes from the start of mixing the A and B portions together. After 30 minutes, it becomes harder to smooth/level out the silicone so make sure to use your time wisely and plan things out beforehand.

4) Once dried, DO NOT TAKE THE SILICONE OFF THE ACRYLIC. The idea is for the silicone to have no bubbles and stick to the acrylic. By taking the silicone off when it dries, air bubbles will be introduced in between the silicone and acrylic which is not ideal.

My Setup:

The sorta Clear 40 arrived in this little package with two different parts. Part A is the tub with the silicone which is sticky and thick, and Part B is the activator which is a liquid.

Before starting, I prepared the table (like the video) by putting an old table cloth over it, and laid newspaper down and put the acrylic on top. It’s hard to see the acrylic since it’s very transparent. Since I didn’t have U-channels to put on the sides of the acrylic for leveling the silicone, I put layers of blue tape on each side. I continued stacking tape until it measured 1mm above the acrylic which came to 8 layers of tape on each side.

I used a straight metal beam (purchased at Home Depot for $2) for leveling the silicone. The beam fits over both sides of the acrylic where the tape is and glides smoothly over the acrylic about 1mm above it.

Here you can see a closer picture of the tape and setup. Once the leveling of the silicone is completed, I placed blue cups around the acrylic in order to hold up cardboard and a cloth while the silicone cures (dries).

Once the silicone is leveled out and the cups are in place on each side, I placed a cardboard box on top of the cups. This gives room for the silicone to cure as a sheet will be placed on top of the box.

Finally, another old table cloth was positioned on top of the cardboard. This is necessary so that the silicone doesn’t acquire dirt as it sets.

Well, I recieved a couple samples of possible compliant surface silicone sheets. Unfrotunatley after some testing, I’ve found they won’t work for FTIR use.The first is from www.rubbercal.com. The durometer (hardness) of the sample is just too high (probably around 70) and therefore doesn’t stick to the acrylic at all. The other sample I recieved is from Rubber House on ebay. This sample is just too thick (1/16″), although it may be a great alternative if the supplier ever gets 1/32″ or thinner sheets in stock.

Since these samples did not “do the trick” and other mentioned brands posted on nuigroup.com aren’t ideal, I’ve decided to go ahead and order Smooth-On Sorta Clear 40 since it has been recommended on NUIgroup. This means I will be pouring my own silicone rubber sheet If everything goes as planned, this will also be the cheapest way of getting a compliant surface. It costs about $33 + $12 (for shipping) at the Smooth-On webstie for a trial size (2.2lb) which should be big enough to make a 36″ x 48″ size silicone sheet (1mm thick). That’s about double the size I need.