(Model) Helicopter Physics

sideways helicopter

If you’ve ever wondered how a helicopter is able to fly, or would just like to see some awesome RC piloting, the four videos after the break should be just the thing! Although the basic physics of how one works is explained in the last three, one would still be hard pressed to explain how [Carl] is able to fly his RC helo the way he does. The video has to be seen to be believed or even explained, but one of the simpler tricks involved taking off a few feet, doing a forward flip, and flying off backwards and upside-down!

As explained in detail in the other videos, a helicopter is controlled by something called a swash plate on the main rotor, which in short translates a linear action into a rotational one. The same thing is done with the tail rotor, but you’ll have to check out the videos after the break for a full explanation! Really ingenious that someone could come up with this analog control system to use before computers were available.

Of particular interest to physics geeks, an explanation of gyroscopic precession is given in the fourth video. Controlling a helicopter may not work exactly the way you thought!

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[Linus] wins the Millennium Technology Prize

[Linus Torvalds] pumped out Linux roughly 20 years ago and has now won some pretty major recognition for his contributions. We’ve seen different flavors of Linux installed on virtually everything you can think of, even on a dead badger. This prize is being compared to the Nobel Peace Prize, since there isn’t a Nobel prize for technology(why not?).

While some might be wondering what the big deal about Linux is, consider this quote from the ZDnet article for a moment.

Is it deserved? Well, judge for yourself. Since Torvalds created Linux in 1991, it has become the world’s most ubiquitous operating system it powers the popular Android phones and eight out of 10 financial trades; it runs Amazon, Facebook, Google, Twitter and other major web networks. It is the dominant OS for supercomputers, supporting nine of 10 of these major systems, and is the preferable platform for cloud computing.

 

DCPU-16 running Pac-Man

If you’ve been trying to think of stuff you can do with the DCPU-16 this may inspire you to write a clone of  a classic game.

This version of Pac-Man was written using a sprite system with a 16 color pallette. It runs in an HTML-based emulator, so you can even monkey around with the assembly code to help you figure out how it works. But if you’re not into writing code that is this machine-close, you can just click the ‘run’ button and use your keyboard arrows to play through a level or two. You’ll notice there’s only one game board available so far and some things are still missing like that familiar waka-waka as he gobbles up the dots. Let us know if you mange to extend the features of this version.

In case you missed it, this emulator is running the DCPU-16 spec from Notch’s new game, 0x10c (. We have no idea how that’s going to shape up, but getting in on the game early will pay off it turns out to be as popular as Minecraft.

Simple proximity sensor

[Dustin Andrews] built this add-on board which works as a proximity sensor. He wanted a standalone sensor for his Arduino projects which would use a single pin as a trigger. This lets him alert the Arduino when an object approaches the sensor without the need for polling or extra code on the Arduino side of things.

As you can see, a single chip on the board takes care of all the work. That’s an ATtiny13, they’re inexpensive and sometimes you can even salvage them from consumer electronics like this color changing light bulb. The microcontroller monitors the phototransistor which is wrapped in electrical tape to isolate it from the IR LED emitters on either side. This setup creates a reflective sensor. When an object nears the board, the infrared light from the emitters reflects off of it and onto the phototransistor. And since the Arduino works as an AVR programmer you don’t need special hardware to program the device.

Computer control for your Xbox controller

This wiring nightmare lets [H. Smeitink] map all the buttons from an Xbox 360 controller to his PC. It gives him the ability to push control input from his PC to the console. But it goes a step further than that because it actually acts as a pass-through device. He connected a wired controller to the computer and uses a program he wrote to translate those inputs and send them to the hacked controller.

The software is written in C#. It’s got a recording function that lets him save the keypress data from the wired controller while it’s sent to the Xbox in real time. When he finds a combination that he uses frequently he plucks out those commands, sets them up as a macro, and assigns one of the buttons to execute it. The controller hack uses one transistor for each button, and a PIC 18F4550 which controls them and provides USB connectivity with the PC.

This isn’t one nice package like some integrated rapid-fire and macro solutions we’ve seen. But it certainly opens up a lot more possibilities. See for yourself in the clip after the break.

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Building a computer with discrete transistors

You’re going to want to do some stretching before undertaking a soldering project like this one. We’re betting that the physical toll of assembling this 4-bit discrete processor project is starting to drive [SV3ORA] just a bit crazy. This small piece of electronic real estate is playing host to 62 transistors so far, and he’s not done yet.

It’s one thing to build some logic gates in Minecraft (and then turn then into a huge 16-bit ALU). But it’s another thing to actually commit to a physical build. [SV3ORA] does a great job of showing the scope of the project by posting a tight shot of one inverter, then three in a row, then the entire 8-bit address and display system. These gates are built on the copper side of the board, with the power feed, LEDs for displays, and jumpers for control on the opposite side. We’re excited to see where he goes with this project!

But hey, if you don’t want to do that much soldering there’s a lot you can do on a few breadboards.

Building an Arduino Chiptunes project inside an FPGA

From time to time we find ourselves in the mood for some Chiptunes. You know, the music that accompanied all of the best 8-bit console games? These days there are a lot of projects that use the audio chips of yore to recreate the sounds, but you’re always faced with the issue of sourcing those parts. [Jack Gassett] took some inspiration from one of those projects, but solved the rare hardware dilemma by building his own Chiptunes MIDI device in an FPGA.

He saw one of our features on an Arduino controlled YM2149 programmable sound generator. He realized that you can already find FPGA libraries out there that mimic this sound generation hardware, and he’s already done extensive work with an Arduino soft processor. Why not combine the two?

He’s using a Papilio FPGA with a wing that includes a MIDI connector and audio-out jack. As you can hear in the clip after the break this sounds just like the real thing. And he’s got plans to roll as many different types of sound generating chips into the mix as possible. You know, one FPGA synth to rule them all.

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