[Jim] used a logic analyzer to do some in depth analysis of the Syma 107G helicopter’s IR protocol. We’ve seen work to reverse engineer this protocol in the past, but [Jim] has improved upon it.
Instead of reading the IR output of the controller, [Jim] connected a Saleae Logic directly to the controller’s circuitry. This allowed him to get more accurate timing, which helped him find out some new things about the protocol. He used this to create a detailed explanation of the protocol.
One of the major findings is that the controller used a 3 byte control packet, which contradicts past reverse engineering of the device. There’s also a new explanation of how multiple channels work. This allows multiple helicopters to be flown without the controllers interfering.
The write up is quite detailed, and explains the reverse engineering process. It also provides great information for anyone wanting to hack one of these low cost helicopters. From the details [Jim] worked out, it would be fairly easy to implement the protocol on your own hardware.
We stumbled onto [Staci’s] videos a while ago when we posted this big tesla gun. While it wasn’t the first portable coil we had seen, it was certainly an impressive implementation. In the comments we found [Staci] had already been making these for a while. Hers were big and small, had awesome modulation, and looked freaking cool too.
It also should be pointed out that [Staci] donates her coils to people when she’s done! Let me say that again, she gives them away to groups of people that could use them. That deserves some respect.
Unfortunately, [Staci] didn’t document her builds in great detail at the time. She has added some information recently though. You can read about her first working prototype from 2006, or a slightly more modern one here.
Of course, the real fun is in seeing them work.
Continue reading “[Staci Elaan]’s awesome portable tesla coils.”
[Andrew] has enjoyed the company of [Pepper] the parrot for more than a decade, but the screeching of a bird in the next room is something you just don’t get used to. [Pepper] gets very lonely some times, and short of having someone carry him around on a shoulder, there’s not much that will calm this parrot down. [Andrew] had the idea of allowing [Pepper] to wander around the house with the help of a mobile platform. Thus was born the Bird Buggy, a parrot-controlled vehicle built just for [Pepper].
The buggy itself is a basic two-wheel drive platform driven with a small beak-compatible joystick mounted just forward of [Pepper]’s perch. With this system, it’s possible for [Pepper] to follow [Andrew] through the house. [Andrew] wanted to make sure [Pepper] couldn’t drive into walls or table legs, so a suite of sensors on the front stops the buggy whenever an object is detected.
One very cool feature of the bird buggy is its ability to drive itself to a recharging station. It does this with the help of a webcam and OpenCV and a pair of markers just behind the charging port. When the Beagleboard on the buggy sees the green and yellow markers for the charging port align, it knows its directly in front of the charging port.
You can see [Pepper] driving his new whip around after the break, along with a very cool demo of the bird buggy docking with its charging port.
Continue reading “Bird buggy soothes a screeching parrot”
It’s the end of the semester for [Bruce Land]’s microcontroller design class at Cornell, and the projects coming off the workbench this semester look as awesome as any before. For their final project, [Alexander Wang] and [Bill Jo] designed an audio frequency spectrum analyzer using two microcontrollers in a parallel setup.
This spectrum analyzer takes an audio signal from an iPod, phone, or CD player through a 3.5 mm jack and displays the level for dozens of frequency bands much like an audio visualizer in iTunes or a nice car stereo display. To display these frequency bands, the spectrum analyzer first needs to perform a Fast Fourier Transform on the incoming audio signal. While FFT is extremely fast, the calculations are rather hardware intensive; calculating the frequencies and displaying them on a TV would be a bit much even for the ATMega1284 used in the project.
To graph the audio signal on their small display, [Alexander] and [Bill] broke the build up into two parts – one to do the math on the audio, and another to generate the NTSC video signal for the display.
As seen in the video after the break, the spectrum analyzer works wonderfully, and even though it only functions up to 4kHz, it’s more than enough to see what’s going on in most music.
Continue reading “Building a spectrum analyzer with parallel processing”