Simulating PenTile RGBG displays

Here’s an interesting experiment that lets you simulate PenTile displays on a normal LCD monitor. [Barrett Blackwood] wanted to test out how some graphics look on PenTile RGBG displays with different pixel densities. These PenTile RGBG matrices are sometimes used in OLED displays. For instance, the Nexus One smart phone features a display of this type. Because red, green, and blue OLEDs emit different intensities of light, the pixels are laid out differently from LCD panels in order to balance the color mixing. Our eyes see the green light very well, and so green sub-pixels are made much smaller than their red and blue counterparts.

Because the hardware layout is different, some graphics appear to have crosshatching artifacts in them when viewed on the PenTile displays. [Barrett] made the example above to simulate how graphics look on a traditional LCD screen (image on the left), and how they appear on the PenTile scren (image on the right). The magenta hue seen above is a result of resizing the image. Since the simulation method turns off 1/3 of the green pixels in the image, resizing it ruins the careful calculation. It must be view at a 1:1 ratio to see the image correctly, at which point the magenta magically disappears.

Patching into Android music control

Here’s a look at the TRRS cable that Android phones use. [Rich Kappmeier] want to control the music player on his Nexus One while driving. It’s not necessarily a safe endeavor if you’re staring at the screen and poking away with one hand while trying to stay in your lane. A little bit of research helped him figure out how the hardware in a headphone controller worked and he decided to incorporate that into a connector cable for the car.

The control signals rely on a specific resistance between the TRRS function ring and ground. Once he worked out the chart above and targeted the correct resistance values he built a rocker switch for Fast Forward and Reverse, as well as a Play/Pause button into the connector cable. You should be able to use this for more than just music control. Take a look at our Android Development tutorial and see what else you can come up with.

[Thanks Alastair]

OLED hack saves juice on Nexus One

Want to really stretch the battery life on your phone? If you have an OLED display [Jeff Sharkey] may have the answer. He did some testing with his Nexus One to see if color alterations can save on current. Darker colors draw less amperage and he found that the red pixels are the most efficient. He did a little work with SurfaceFlinger, which handles the display on Android devices to make this easy, but what will you get by going red? He measured that using only the red pixels dropped the current use down to 35% of what the full color display was pulling. This reminds us of those efforts to save energy by running a black background with Google. Whether you use it or not his post is an interesting read.

Careful! That gas pedal is a Nexus One

Indeed, the gizmo above is meant to be used as a gas pedal. [Grant Skinner] came up with the idea to control slot cars using an Android phone as a gas pedal. He coded the software for the handset and a computer using Adobe AIR. Once connected, the computer is sent the accelerometer data from the phone, relaying the speed control to the slot car track with the aid of a Phidgets motor controller. See it ‘go’ after the break.

We’ve seen the Phidgets board used in several projects like the augmented vending machine and the plotter white board. What we haven’t seen is hacks that make use of AIR, a framework we looked at two years ago. If you’ve got hacks that make use of AIR we want to hear about them.

[Read more...]

Wii remote connectivity for Android devices

[Pikipirs] developed an app that lets you connect a Wii remote to an Android phone. After the break you can see it used with a Sega emulator. The button presses seem very responsive, making for a nice gaming addition if you care to carry around the Wiimote in addition to your phone. It certainly seems to work better than the Wii remote + iPhone hacks we’ve seen. Pick it up from the Android store or download the APK from the thread linked at the top. This is an alpha version so don’t be shocked if it’s buggy.

[Read more...]

Adding RAM to the Nexus One without soldering

Want 21 megabytes more ram in your Nexus One? [Coolbho3000] worked out a way to tweak the kernel and remap memory usage to free up some resources. That means this comes as a custom kernel image requiring no hardware alteration. Try it out and share your experiences in the comments. But if you don’t need more ram you can just upgrade to the most recent kernel.

[Thanks Juan]

Running bleeding edge on Nexus One

We like to run the newest software available. We often encounter problems and things that don’t work because of this, but with open source that just give you the opportunity to contribute and make the package better. Now you can take the fun and daring of bleeding edge to your phone by installing the latest Linux kernel on the Nexus One. [Jon Lech Johansen] wrote up that eight step process to install 2.6.32, which should take you just minutes if you already have the Android SDK installed. If you don’t what are you waiting for?