How to build a 23″ Android tablet

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.

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Extending the usability of touchscreens

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.

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Converting a scanner into a touchscreen

[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.

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eeePC touchscreen retrofit

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.

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Mac tablet keeps the look of the donor-Macbook

[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. Continue reading “Mac tablet keeps the look of the donor-Macbook”

Car computer requires PIN for ignition

[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.

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Linux tablet built around a BeagleBoard

[Justin] shows us how to make a Linux tablet out of a BeagleBoard. You may remember [Justin's] work at liquid cooling an Arduino. For this one he moved past the AVR hardware but took the idea of shields along for the ride. The device above is something of a Linux tablet, with a touchscreen shield on top of the BeagleBoard, and one below it for power. He’s selling these as kits which include the 480×272 OLED display as long as you can handle the fine-pitch soldering for those headers. We’re not sure our hands are steady enough for the challenge.
[Thanks Will]