Embedded above is an interesting multitouch demo by [Lahiru]. The goal of the project was to find an easy way to retrofit current LCDs for multitouch. Instead of using infrared or capacitive recognition, it uses a standard webcam mounted overhead. To calibrate, you draw polygon around the desktop screen as the webcam sees it. The camera can identify the location of markers placed on the screen and their color. iDisplay can also recognize hands making the pinch motion and sends these as touch events via TUIO, so it works with existing touch software. It’s written in C++ using OpenCV for image processing with openFrameworks as the application framework.
[Jacob] wrote us to show off his latest project. He built his multitouch interface out of an LCD monitor. We’ve seen plenty of multitouch projects here, but usually they are projection style. This project uses the panel out of an LCD, with the diffusers and backlighting removed. The panel itself is fairly transparent, so a webcam with IR filter can see the light pens right through it. It does seem a bit dim in the video, we’re wondering if it is better in real life.
[Alex] sent us this project he’s working on where he’s building a phototransistor based multitouch input system. Though many people have built systems with phototransistors, most of them are quite large and very sensitive light and dark variances. [Alex] has done some fancy background subtraction through software. He believes his is the first to do this. As you can see in the video after the break, it seems impervious to the lamp he is moving around, and still fairly sensitive to his hand. We’re curious to see where he takes this one.
June 6th is the date of the upcoming Global Hackday. This time, focusing on cheap tangible interfaces, mainly trackmate. They want as many people to join as possible, even if you’re not comfortable with code. We’ve covered the construction of the trackmate surface before, now build one and get in there and contribute.
[Tom Gerhardt] has made this very interesting mud interface for a computer. Follow the link to see a video of it in action. It appears as though he’s using a laser grid of some kind to establish elevation. We might be way off on that though, there aren’t any details on the construction. He does mention that it is an open source hardware and software project, so maybe the details are available on request. In the video you can see it running as a projection surface where people are interacting with items directly on the mud. You can also see it being used as an external input device. People play Tetris using it in that example.
UPDATE: [Moon] reports from the ITP show that the tub has a 16×12 grid of generic pressurs sensors on the bottom. These feed into a MacBook Pro which is projecting on the surface. Despite the sparse grid, [Tom] says he gets good resolution by interpolating between sensors; it can detect a resting hand pivoting on the surface.
NOR_/D has just released their newest multitouch display system. The TouchKit Spark features a larger 35.4×23inch display surface than its predecessor, the Run. It uses ultrabright IR LEDs around the screen’s border for FTIR multitouch sensing. A high frame per second IR camera is included to increase tracking performance. The screen is fully assembled, but you need to provide your own projector and case. It can be built at table height or as low as 20inches. The device is designed to work with OpenFrameworks, but future software releases will have TUIO support.
iPhones and iPod touches have many advantages over the plain iPod. Have you ever wished you could advance tracks without looking though? That is a perfect example of where the current display/ input trends are lacking. There is no tactile feedback. [Chris Harrison], a Ph.D student at Carnegie Mellon has been working on an alternative.
His displays are rear projected and multitouch like many of the other multitouch systems we’ve seen. However, his also offer tactile feedback by changing their physical shape. Much like a vac-u-form, he is using vacuum to deform a flexible surface over different shapes. Not only are they able to do simple 2 state systems where you have smooth, then vacuumed, they can also do a third state by pressurizing the inside of the display. You can see several variations in the video.
10:19AM “They talk over the dock, and wirelessly over Bluetooth. Things like playing and pausing music, getting artwork — or you can build your own custom protocols.”
10:19AM “Now here’s a class that we think will be really interesting — medical devices.” Scott’s showing off a blood pressure reader that interfaces with the iPhone — wild.
10:18AM “Here’s an example — an FM transmitter. With 3.0, the dev can build a custom app that pairs up with it, and automatically finds the right station and tunes it in.”
10:18AM “With 3.0, we’re going to enable accessory developers to build custom apps that talk directly to that hardware.”
No solid connection specification has been published yet. We’re excited about the prospect of developing our own accessory hardware, but we wonder what sort of hoops you’ll have to jump through. Apple doesn’t have the best track record when it comes to approvals. Just this week they denied MSA Remote client App Store entry; it’s a multitouch client that uses the standard TUIO protocol. Prepare for similar roadblocks in the future.
We love keeping track of new interaction technologies and this new touchscreen by Stantum looks especially promising. Engadget shot a hands-on video with it at the Mobile World Conference. It’s a resistive screen, so it can be used with both fingers and styluses (unlike capacitive screens). It’s sensitive enough that you could use a brush too. The screen supports any number of multitouch points and does pressure sensing based on the size of the detected fingertip. The touch detection is actually more accurate than the screen can display. Stantum is hoping mobile manufactures will pick up their input framework for inclusion in new devices. The resistive touchscreen was built to Stantum’s specifications (it won’t work with current phones), but they say it wouldn’t be hard to go into mass production.
[Dave] sent us these fantastic instructions on how to hack a rear projection tv to be a multitouch interface. They’ve converted a 67″ inch TV by adding a couple of PS3 eye cameras and an infrared laser plane. There’s lots of great information, like how to replace the lenses on the PS3 eye cameras and how to create the custom fittings needed to make it all fit nicely. You can download the code, but it is Mac only. They claim that this is the first conversion of a commercial rear projection TV to multitouch, but we know better. You can see a video of it in action after the break.
Touch screen interfaces are generally hard and flat. Impress tries to break from that tradition by making the display flexible. Allowing you to feel more like you are interacting with the display. In the image above, the circles seem to physically fall into the dent made by your fingers. Another application shows some rudimentary 3d modeling being done by physically pushing on the vertexes. This prototype is very interesting, we’d love to see much higher resolution on the input side of things. It states that it does pressure sensitivity, but we weren’t able to distinguish it in the video. Maybe you can, catch the video after the break. Maybe laying one of these on some foam would be another alternative.
If you’ve ever wanted to play with tangible tracking systems quick and cheap, you might be interested in this super quick tracking surface for trackmate. Trackmate is open source software for physical object tracking. Making a surface for it isn’t that hard in the first place but this one is probably the easiest. All you really need is some Plexiglas, some c-clamps and a web cam. The whole thing packs into a backpack or over the shoulder bag. This would be perfect for live performances.
Reader [Ramon Viladomat] sent in what he has been working on over the last year at the Universitat Pompeu Fabra in Barcelona. Tired of see nothing but zooming map demos, he created a roleplaying game that takes advantage of the reacTable’s multitouch interface. Along with multitouch, the reacTable also uses tangible fiducial markers to represent objects and as an alternative input method. Embedded above is a video demoing the interface and gameplay (starts at 3:43). The game lets you move your miniature through a virtual world. The surface shows you how far you can move dynamically as your action points regenerate and slowly reveals more dungeon as you discover it. You can pause the action and use gestures to set attack patterns. We really like this demo and would love to see someone build one using a popular tabletop game like Warhammer 40K. Embedded below is a demo of the associated map editor.
[Luke Hutchison] has come up with a rather clever hack to get multitouch support on the G1. He wrote a patch against the Synaptics touchscreen driver. When two fingers are placed, the driver reports the x/y of the midpoint and a radius for the size field. If only one finger is used, the size is reported as zero. The nice thing about this approach is that it’s backwards compatible; the extra data will be ignored by current apps. Unfortunately, Google’s Android team says that if multitouch is ever added, it would identify individual fingers and definitely not using this method.
