[HankDavis] sent along this link to a video showing a tutorial on how to make touch sensors using a “darlington pair”. In the video we are taken through the idea and how we’re going to construct it.  [Thad]explains in detail how this works in simple terms and illustrates it clearly. Unfortunately they don’t show an actual constructed system, but this is so simple you could toss it together quickly and see for yourself. This is a great lesson on how to get a simple touch sensor into your projects. This video appears to be one of a series of class visuals, and you can find several others on youtube under this account.

This touch screen relies on measurements from two range finders to track your finger as you press buttons. [James Alliban] put this together as his first Arduino project. We’re familiar with [James'] background because of his informative augmented reality business card. As the Arduino picks up data from the range finder it sends it to a Flash script that is running on the PC.

As we watched the video after the break a lot of questions came to mind. What kind of angle do these Ping sensors have? Will there be interference problems if they were placed perpendicular with each other? Would you get more accurate data if they were not both on the top of the screen? For now this is just a preliminary experiment, but we like the concept and may give it a try ourselves.

[Thanks Juan]

[Andrew Jenner] pulled off something amazing with this Physical Tone Matrix. He wanted to build a physical version of a flash applet he had seen. Two layers make up the main user interface. The top layer is a sheet of acrylic that acts as a touch interface and below there’s an LED matrix. [Andrew's] touch interface uses wires running throughout the acrylic as contacts which are polled via transistor pairs. As you can see in the video after the break it works well and we like the fact that there’s a tactile component (due to the bumpy wires) you don’t get when working with a touchscreen.

The 16×16 grid of LEDs on the bottom layer correspond to each ‘button’ on the touch matrix hand have some extra functions such as playing Conway’s Game of Life. This fantastic build still has a couple of kinks to work out, most notably the interference in the audio circuit, but we’re quite impressed at what he’s achieved quickly. Plus, this is more economical than a monome and larger than some of the monome clones we’ve seen.

This security system called G-spot requires that you touch a special place on the car prior to attempting to start it. This is pretty slick as it could be completely un-obvious and doesn’t require any special fobs or minor surgery. With the right placement, no one would ever notice that you had touched it.

[via HackedGadgets]

Reader [Chad Essley] asked us:

“I’m wondering if the vast knowledge base of HackADay’ers out there might know of some way to turn almost any laptop into a touch screen of some kind. Actually, any surface.”

He has an older Wacom Tablet, and would like to be able to add resistive touch screen capabilities so that he isn’t forced to use the Wacom pen. Being an artist and part time hacker, he even summed up the question in a comic-style post.

We know of tools such as the EZscreen instant touch:

The chill of autumn is upon us, and with it comes the awkward sport of trying to work touch-sensitive phones and gadgets with gloved fingers. One can try toughing it out with fingerless gloves, or we’ve seen some costly solutions in the forms of specialized gloves and capacitive-compatible styluses, but sometimes simple is best: all it takes is a few stitches of conductive thread in the fingertips.

Conductive thread is available from various sources; SparkFun Electronics comes naturally to mind, but most vendors carrying the LilyPad Arduino will stock a suitable thread as well. Don’t fret if you’ve never sewn before — just a few simple loops are required, and it doesn’t need to be especially tidy. In principle this should work for trackpads and capacitive mice as well, if you use those in the field. For multitouch devices, add a separate conductive bit to each fingertip.

[via Lifehacker]

[Humberto] from NerdKits is one of our favorite tipsters. We like how he can take a concept that seems so extremely complicated, in this case touch capacitance sensing, and present it in a clear and concise manner thats impossible to not love. As previously mentioned the most recent NerdKits hack is on touch capacitance; by using a resistor capacitor pair and some clever switch timing, anyone is able to detect the presence of a human limb. Now who’s going to be the first to adapt this concept further in their own hack?

[Agent420] brought up this touchpad and VFD hack in the comments on our capicitive sensor guide post. He had broken dell laptop from which he harvested the touchpad and an HP laserjet that contributed the VFD. Though the touchpad communicates using standard PS2 protocol, he wanted to use it with his Atmel 8535 AVR which required him to write some custom code. In the picture above, you can see the VFD displaying the coordinates of his finger. You can download his code as well as the spec sheets for the different pieces on the project thread.

Embedded above is a demo video of an iPhone running a Linux 2.6 kernel. The iphone-dev team has created a new bootloader called OpeniBoot. The bootloader lets you boot into a Linux console, which you can talk to over a USB serial device. They’ve got busybox working, but there is no touchscreen support yet. The instructions are not that difficult and include how to back up your settings. It works on first and second gen iPhones and first gen iPod Touch. This is a very early port, but the future is wide open… Android iPhone?

[via Gizmodo]

Several people have taken it upon themselves to fashion Mac tablets of their own, varying from extremely professional looking finishes down to duct tape and wire. Lets take a look at some of the more popular ones out there.

First lets go to the place that started many of these projects. Though not strictly a Mac tablet, the projects at Bongofish.co.uk deal with making your own Cintiq. The instructions are quite in depth and the forums have several Mac projects to view.

Back around 2004, [Joseph DeRuvo Jr.] put together this fantastic little mod. He grafted a Troll Touch screen to a Mac laptop and made a custom case for it. He did a fantastic job of enclosing everything and making it look great. One cool feature is that the cover that protects the screen, folds back to form a stand when needed. This guy put a lot of hard work into this and it shows.

Another extremely polished model is the iTab. Inspired by the DIY Cintiq at Bongofish, [wiestudios] has put together this beautiful piece. Going more with Wacom than Mac style, it’s another fine bit of engineering. It even has an apple and crossbones etched in the back!

Polish isn’t everything though, sometimes simplicity can bring a project into the hands of the average Joe. Check out [Florian Mourer]‘s ongoing project. He plans on building a custom enclosure at some point, but for now he’s got a pretty simple modification working. Again, this one uses a Wacom board so it is pressure sensitive. Unlike the others, he is limited to only a portion of the screen being sensitive due to the size of the tablet he had available.

Our very own [Caleb Kraft] has also ventured into the area of making Mac tablets. Using a cheap Wacom board, some duct tape, a screw driver, and a torx wrench, he shows us how to build a pressure sensitive Mac tablet in 15 minutes.

With the advent of the iPhone, it seems that a Mac tablet should be on the horizon. This is just one of the many cases where hackers have the technology first.

Following today’s earlier post on data gloves, HandUSB is a glove interface designed to relay fingertip touch data to a computer via USB. Although the gloves themselves are not extremely interesting or useful for your average hacker, the project has some good documentation. The electronics are all open source and he has links to the EAGLE files and the AVR Libc code. You can also find a demo program written for DOS. This project uses AVR-USB by Objective Development so if you are looking to move on from your USB-serial chips, this project would be a good resource to study.

[via YourlTronics]

The Novint Falcon is one of the first mass produced and consumer friendly versions of a haptic feedback device. With force capabilities of 2lbs and a resolution of 400dpi the unit can interact with several software programs and video games. The unit sells for around $239 and includes several compatible games.

Some inventors like [Steve Yohanan] feel robots need better response to the basic human touch. His latest creation the Haptic Creature is a small bunny that responds to touch through pressure sensors and then responds. Different forms of touch result in the creature changing it’s breathing, purring, and of course wiggling its little bunny ears.

On the fun side of things, we have several toys making their way into the market with haptic feedback features built in. The Pleo being one for of the more advanced examples with it’s almost unlimited amount of responses and feedback. The toy itself is touted as something to interact with as opposed to simply control. UGOBE is also talking up its therapeutic value for both children and adults.

While some of this technology may seem out of reach of DIY, there is one organization trying to bring open source to the scene. Backed by SenseGraphic the H3D API is an open source initiative to help programmers interface with various haptic devices. Browse their hall of fame page to see what individuals and universities have done with the API. This PDF also provides a broad overview of the history of haptics.

We’ve covered a ton of haptic projects here on Hackaday: D’Groove a force feedback turntable, a personal haptic radar, a PSP with feedback, and even reverse engineering the Falcon we mentioned earlier.

[via Gizmodo]