R/C blimp uses a party balloon for lift

Here’s a really tiny r/c blimp that doesn’t need several cubic feet of Helium to get off the ground.

Instructables user [masynmachien] has been building r/c blimps for over a decade now, and this latest build is meant to have the same specs as this nanoblimp. The build is based on an 11-inch party balloon that can provide about 11 grams of lift. This doesn’t allow for much leeway in terms of weight, so [masymachien] used hacked-up servos for the motors.

The blimp is an exercise in saving weight – just about every component that can be removed from the build is thrown away. The results are pretty impressive. The entire blimp weighs about 10 grams on the ground. [masynmachien] also tried a 14-inch balloon with an 808 key fob camera with very good results.

The blimp looks pretty good when flying around a room. [masymachien] seems to have a lot of control from a minimal component count. You can check out the party blimp in action after the break.

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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.

Pyxis 3 hits beta; rebranded as Gadgetos

The beta version of Pyxis 3 is now available. Skewworks continues to develop the ARM operating system, and with the transition to version 3 they’ve given it a new name: Gadgetos. One big difference from Pyxis 2 is that the new kernal is closed source. But they’ve taken steps to ensure that the OS is still hardware independent. This is done by reworking the kernel to allow driver loading at run time from an SD card.

The user interface has also changed a bit. Gadgetos relies entirely on a context-based menu system. The minimum input hardware requires a touchscreen LCD and one tactile button. By holding that button, a menu pops up in the center of the screen. This menu is different based on where it is called (this is where context comes in). If you’re at the desktop screen, you get options to load programs, etc. If you pull up the menu while running an application you’ll see the options available for that app. To see more about the new navigation system check out the video after the break.

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Lighted fan pull saves you from flailing around in the dark


Like many people, [yardleydobon] had a hard time locating his ceiling fan’s pull chain at night when his room is completely dark. Rather than continue to flail around blindly grasping for the chain, he decided to find a way to illuminate it instead.

He started off by disassembling a solar garden light, retaining the solar cell, photoresistor, and batteries. After paring down the electronics to the bare essentials, he mounted them inside a plastic battery storage case which he attached to the outside of the fan’s lamp. [yardleydobon] then ran a pair of wires from the electronics box down to end of the chain, where he added an LED and a translucent pull to diffuse the light.

He admits that it’s not the nicest looking modification around, but it does the job in a pinch. He has some ideas that he may put into play if he has the time to revise the design, and we bet that many of you do as well. If so, be sure to share them in the comments.

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Buzzer project for classroom team games

Want to host a Jeopardy tournament with your friends? Looking to add a bit more fairness to your school’s knowledge bowl? Perhaps you should build some buzz-in hardware of your own.

Here you can see [Matt Hanson's] take on this idea. He used one Arduino to gather not just buzzer info, but also keypad data from four satellite controllers. Each has an RJ45 jack, allowing it to connect tot he base unit with an Ethernet patch cable. We like the color coding that [Matt] chose, which matches the color of the arcade button to the keystone jack on the base. And of course the fantastic look of the water-jet cut cases isn’t lost on us either.

You may wonder why he included a key pad on each controller? It looks like he and a few others worked together to develop a team-based math game for use in school.

Tiny audio switcher eliminates repetitive plug swapping


[Phil] uses both his computer’s speakers and a set of headphones while working at his desk, but he was growing tired of constantly having to remove the headset from his sound card in order to insert the speaker plug. He’s been meaning to rig something up to make it easier to switch outputs, but never seemed to get around to it until he recently saw this LAN-enabled audio switcher we featured.

His USB-controlled switch features a single audio input and two audio outputs, which he mounted on a nicely done homemade double-sided PCB. The switch can be toggled using any terminal program, sending commands to the on-board ATtiny13A via an FT232R USB to serial UART chip.

The switch’s operation is really quite simple, merely requiring [Phil] to type in the desired audio channel into the terminal. The ATiny and a small relay do the rest, directing the audio to the proper output.

Follow up: Star Wars tree gets an upgrade


We asked, and [Zach] listened.

Earlier this week, we featured a circuit he built which allowed his tiny Star Wars Christmas tree to visually replicate the series’ theme song. Several of you, along with myself, thought it would be far cooler if the tree also played the music to accompany the light show, so [Zach] set off to add that functionality.

Worried that the music would get annoying if it played along with the lights constantly, he tweaked his circuit design to incorporate a piezo buzzer that could be easily switched on and off. After wiring it to the MSP430 driving the light show, he tweaked the program to output signals to both the light string and buzzer simultaneously.

While the light show accurately represented the song, he initially ignored flat and sharp notes as they would be indistinguishable to the eye. In audio form however, the missing notes would be glaringly obvious, so he re-transcribed the sheet music resulting in the video you see below.

If you happened to follow [Zach’s] lead and put one of these together in your own house, be sure to swing by his site and grab the latest code, complete with audio track.

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