[Chris] just posted his latest tutorial which shows you how to read position data from a resistive touchscreen. These devices are fairly simple, and since they’re used in a lot of consumer electronics you can pick one up for a few bucks. This looks like it is overstock for an old Palm device.

The interface is simple, there’s just four conductors on the tab at the top of the overlay. But connecting to these is a bit of an issue since you can’t really solder directly to them. [Chris] ended up using scotch-tape to hold wires in place, with a paperclip to keep them presses against the conductors. Those conductors are used in pairs, with a positive and negative lead for the X and Y axis. To take a measurement you use I/O pins to connect voltage and ground, then read the voltage that makes it to the gound side using an ADC. This works because the point that’s being pressed on the screen acts as a variable resistor for the circuit. Data for the two axes must be read in separate operations so that the positive voltages don’t interfere with each other.

The nice thing is that once you’ve got it working with a small screen it is easily scaled up. In fact, the 23″ touchscreen used on this Android hack is just another 4-wire resistive device.

You can see a video demonstration of [Chris'] test rig embedded after the break.

It’s not that touchscreen keyboards are horrible, but it’s nearly impossible to touch type on an iPad or other tablet keyboard. A team at the Media Computing Group at Aachen University figured out how to put a series of electromagnets underneath a display to provide haptic feedback for touchscreens. They showed off their tech at the 2011 UIST conference and made their paper available.

For the FingerFlux, as the team likes to call it, a bed of tiny electromagnets is placed underneath a panel display. The user wears a ‘thimble’ with an attached permanent magnet. Driving the bed of electromagnets slightly moves the magnet and provides a little bit of sensation to the user.

The FingerFlux can be used to provide haptic feedback like a keyboard. The system can also be used to model constraints – making sure that users don’t move outside the controls they operate, and can guide the user to the desired button.

A bed of electromagnets would be a welcome addition to tablets, if only to prevent typung luje rhus. Check out the demo of the FingerFlux after the break.

Thanks go to [John] for sending this one in.

If you’re looking to build a really big Android tablet the trick is not to start from scratch. [Peter] pulled off a 23″ Android Tablet hack using a collection of easily acquired parts, leaving the hard work up to hardware that was designed to do it.

He didn’t really build a tablet, as much as he built a big touch-screen add-on for one. He already had a couple of inexpensive tablets on hand to play around with. One of them has an HDMI out port, which let him easily push the display onto a 23″ monitor. He knew the tablet was a 4-wire resistive touchscreen, but he didn’t know if other touchscreens with the same number of connectors and be directly swapped and still work. To test this, he cracked open a second tablet device and connected its touchscreen to the first one’s hardware. When he was met with success it was time to source a couple of 23″ touchscreen overlays to test with the external monitor. As you can see in the clip after the break, it works like a charm!

[Peter] was inspired to write about his experiences after seeing the 23″ Android tablet video in our recent links post.

Fanboys may be in shock from seeing duct tape applied to the screen of an iPad, but we can assure you it’s in the name of science. [Michael Knuepfel] is working on his thesis for the ITP graduate program at the Tisch School for the Arts. He managed to augment the usability of touchscreen devices by adding hardware to them.

What he’s come up with are devices for both input and output. The output devices generally rely on light and color of light displayed on the screen itself which is picked up by a light sensor. The input devices use conductive material to complete a path between your hand and your screen. This lets the capacitive sensing screen detect the presence of your hand, through the conductor. Some of his example devices include gaming controller overlays, encoder rings, and multiple stylus designs.

After the break we’ve embedded [Michael's] teaser trailer which jumps through several demonstrations. It’s plenty to get your mind rolling, but if you want to know more you must watch his thesis presentation. It’s available as an MP4 download on this page. Just search for his name, [Michael Knuepfel] for the proper link.

[via Make]

[Sprite_TM] was cleaning up his hacking workbench when he came across an all-in-one device that had seen better days. After a bit of consideration he decided to tear down the scanner portion of the device and ended up turning it into a multi-touch display.

The scanner relies on a long PCB with a line CCD sensor. This sensor is read in a similar way that information is passed along a shift register. Tell it to take a reading, and then start a clock signal to pulse out each analog value from the pixels of the sensor. In order to scan color images it uses multicolored LEDs to take different readings under different illumination.

[Sprite_TM] takes advantage of this functionality to turn it into a multitouch sensor. The sensor board itself is mounted below an LCD display along with a shield with a slit in it to help filter out ambient light. Above the screen a series of LEDs shine down on the sensor. When you break the beams with your finger it casts a series of shadows which are picked up by the sensor and processed in software. Watch the clip after the break to see it for yourself. It has no problem detecting and tracking multiple contact points.

Adding touch screen capabilities to your computer is really not very expensive, but it’s a huge amount of work to get everything looking the way that it should. [Deadbird] wrote up a step-by-step guide that will help you install touch screen hardware and get your netbook put back together just like new.

The hardware comes in two parts. There’s the transparent film that covers the screen and the driver board that reads the inputs. The film itself has an adhesive layer on the back that sticks to the LCD panel. But to install it you first must remove the panel from the bezel. You’re also going to need a place to house the driver board. [Deadbird] somehow found enough room inside the case for the controller, but he had to remove the keyboard and motherboard to set it in place. This translates to a complete disassembly of your eeePC. But if you’re used to touch-sensitive devices, and have ever found yourself touching an LCD monitor and wondering why the computer is not following the link, this may be worth it to you. You can see the final product in a clip after the break.

[Enigma-penguin] built a tablet computer out of a Core2Duo Macbook circa 2007. The battery exploded, damaging the case and a few components inside. But there was hope for a new life as a tablet computer. He removed the screen and tested to make sure the computer would still function without it by using the video out port.

Putting the whole thing back together as a tablet proved to have some headaches. He worked through problems caused by the addition of a touchscreen between the LCD and the bezel and made the connections work with the screen flipped. The finished product looks so good because the bezel has not been turned around like on other tablet builds. Instead, a viewing window was cut in what would have been the case behind the screen.

There’s a little more to be done yet. The black USB cable seen above is the connector for the touchscreen which he plans to internalize. The magnetic sleep sensor has been relocated to the headphone jack. Inserting a plug (no cord necessary) puts it to sleep for transport. There’s also an on screen keyboard and the ability to change the screen orientation from landscape to portrait. After the break we’ve embedded one of [Enigma-penguin's] demonstrations.

[Thanks Stephen via Neowin and their Forums]

[Ben's] added some nice goodies to his Volvo in the form of an in-dash computer. The system monitors two pressure sensors for boost and vacuum, as well as reading RPM, O2, and exhaust directly. All of this is tied into the touch interface running on an eeePC 900A. But our favorite feature is that the system requires you to enter a PIN to start the ignition. The forum post linked above is short on details so we asked [Ben] if he could tell us more. Join us after the break for a demonstration video as well as [Ben's] rundown on the system.

Ben writes:

Hi, great, glad you like it. The EEE 900A has a 2GB ram upgrade and a 16GB SSD upgrade, running windows 7. I modified the computer so it could fit directly behind the screen, which involved relocating the USB ports, and also using a HP webcam from a broken laptop as a back up camera.

The black box has three circuit boards. I’ll send you some pictures of the most current version later. The first board is for power, It has a 3.3v and 5v regulators to provide the two voltage rails, and the three relays. One relay controls the power supply to the netbook, the second controls the car’s actual starter, and the third controls the auxiliary power and lighting system.

The second board uses two freescale semiconductor pressure sensors, one to read boost and the other to read vacuum. It also has a secondary microcontroller (A PIC18F2550) to read a direct RPM input as well as a wideband o2 sensor in the exhaust. This uC is running in i2c slave mode.

The final board in the back is a PIC18F4550, which has direct control over the relays, the secondary controller, and also directly reads the two pressure sensors. Both controllers run software written in PICBASIC.

Now the part that I like about the interface box, is in order to talk to the computer, it uses only the PIC18F4550′s USB port. one usb connection is all that the computer talks to the car with.

The software running on the netbook is an application that provides a front end to the control box, A PIN is required to be entered, and once the PIN is correct, you are then able to start the car via the
button on the screen. The normal key method of starting no longer works. For security, The interface ONLY sends the PIN number to the control box, the control box has a PIN number saved and encrypted on the PIC’s internal eeprom. The entire application was written in VC++, .net, and provide me with accurate boost, vacuum, RPM, and AFR on screen. Touching a gauge on the screen enlarges it, and minimizes the other two gauges for enhance readability.

It’s all cleanly installed in my 1998 S70 T5, which was an automatic from the factory and that I swapped to manual in January this year. To power the entire system on, you only need to press the unlock button on the keyfob. by time you get to the car, the computer is running, and the control box is connected to my software and waiting. Locking the doors via key fob (using the key on the door also works just as well) tells the contol box to use a transistor to electrical press the EEE’s power button and put it into sleep mode. Once the EEE is off, it cuts power to the EEE, and then both controllers go into sleep mode, drawing minimal current. I’ve left the car for a couple weeks with the entire thing hooked up, got home, and started it right up and drove away. I designed the entire system like any company would, to ensure reliability. There are safety measures that only I know about, that allow me to re-enable the standard key ignition in case of an emergency.

We don’t remember where we read it, but our favorite criticism of the iPad is that is does the same things a lot of other Apple devices do. So why wait until April to get your hands on that functionality? [Alexbates] built his own iPad clone using existing hardware and software. This started with an MSI wind that he used as a hackintosh. A touchscreen was added to the display, the keyboard removed, and the LCD flipped around. Boom, a tablet running OS X was born. This is different from others because [Alexbates] took the time to alter the UI to look like the iPad. Sure, it doesn’t automatically flip the display when rotated and there’s no pinch-zooming. But it does have more processing power and storage space.

We’re more likely to hack our own like this rather than purchase a device we’re not all that enthusiastic about.

[Thanks Jadon via Engadget]

[Ryan] and his wife wanted to have a touchscreen interface in the kitchen to store their recipes and for various music, video, and Internet entertainment. We know where they’re coming from, we’re quite tired or cleaning flour (or worse!) off of our palm pilot screen after baking. The display you see on the wall is just the interface, a computer is stored in the cabinet below the counter. He’s running Windows 7 and using a custom graphic interface which is intended to mimic the looks of the iPhone. He’s sharing the UI as open source and has just started a forum for those interested in trying it out and adding to the available features.

One thing we noticed in his writeup, he prototyped this with an old 2 GHz computer but upgraded the hardware because it was too slow. This pushed to total build price to about $1350 USD. We can’t help but mention that using a Linux based system may have saved him from the upgrade. We know there’s some extremely powerful media software that runs on light hardware specs.

[Thanks Hannah]

[Andrew] wanted a tablet computer but is tired of waiting for Apple to come up with one. eBay and Craig’s list to the rescue, he picked up some parts and built his own tablet. You can take a look at the video tour of it after the break, or peruse parts one, two, three, and four of his work log.

The unit is assembled from a 500 MHz iBook. [Andrew] picked up a touchscreen from ebay and canibalized a USB joystick in order to add some buttons to the keyboard-less design. The end product is quite nice. We’ve wanted a tablet computer to hang on the wall for a long time and this may be the inspiration that gets us there.

Do you find this didn’t satisfy your Apple tablet fix? There’s more to be seen in our mac tablets roundup.

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]

Circuit Ideas Design has posted a digital picture frame project based on their 240×320 16-bit color QVGA display. We made our own digital frame from a smaller screen a while back and this is pretty much the same implementation except with a larger screen and built around the AVR family of microcontrollers rather than PIC controllers.

The thing that piqued our curiosity was the five icons silk screened on one end of the display. That’s right, this is a touch screen. The board also has a built in SD slot and a bit of flexibility for connecting to a microcontroller. It can be controlled from a 40-pin header, or from headers that are designed to work as an Arduino shield. We’d love to get our hands on one but we were unable to figure out what currency the list price was in. Has anyone used this board yet?

Liquidware has put together an interesting kit called the WiNet. It has a battery powered touchscreen controlled by an Arduino. Using an XBee shield, it can send commands to a paired XBee and Arduino attached to a computer. The computer can also update the touchscreen display. This is demoed in the video below. It’s a unique interface, but the TouchShield alone costs $174 so we’re guessing you’re going to be pretty damn confident in your project before you go this route.