Stubby, The Adorable And Easy To Build Hexapod

June 30, 2014 by 23 Comments

stubby

A while back, we had a sci-fi contest on Hackaday.io. Inspired by the replicators in Stargate SG-1, [The Big One] and a few other folk decided a remote-controlled hexapod would be a great build. The contest is long over, but that doesn’t mean development stopped. Now Stubby, the replicator-inspired hexapod is complete and he looks awesome.

The first two versions suffered from underpowered servos and complex mechanics. Third time’s the charm, and version three is a lightweight robot with pretty simple mechanics able to translate and rotate along the XYZ axes. Stubby only weights about 600 grams, batteries included, so he’s surprisingly nimble as well.

The frame of the hexapod is designed to be cut with a scroll saw, much to the chagrin of anyone without a CNC machine. There are three 9g servos per leg, all controlled with a custom board featuring an ATMega1284p and an XBee interface to an old Playstation controller.

Video of Stubby below, and of course all the sources and files are available on the project site.

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[Tymkrs] Tombstone Guitar Amplifier

June 30, 2014 by 16 Comments

tymkrsTombstone

[Atdiy and Whisker], the team behind [The Tymkrs] YouTube channel, are at it again with a tombstone guitar amp project.(YouTube playlist link) Their amp began life as a Philco Tombstone radio which had seen better days. By the time [Tymkrs] got their hands on it, it was just a shell of its former self, as someone had already stripped all the electronics.

The amplifier itself is a disused Leslie tube amp [Tymkrs] had on hand. An LM386 serves as the pre-amp, making this a hybrid solid and vacuum state machine.

The tombstone speaker is especially interesting. [Tymkrs] went with an electrodynamic field coil speaker. Field coil speakers have no magnets, instead using a high voltage (approx 90V DC) coil to create a magnetic field for the voice coil to push against. This sort of speaker was commonplace in the 1930’s, as large magnets couldn’t be made lightweight enough to be used in a speaker. As magnet technology improved, permanent magnets became a staple in speakers.

[Tymkrs] paid special attention to the finish of the amplifier. They brought the tired old radio back to a high shine, then added a Metropolis inspired overlay from aged copper-clad board. The result is an amp that looks great and sounds great!

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A Cloud Of Lightning Detectors

June 29, 2014 by 33 Comments

strikes

Here’s an interesting project to plot every lightning strike on Earth. Blitzortung is a project that uses many extremely low-cost sensor boards packed with an amplifier, microcontroller, and an Ethernet socket to detect lightning strikes. When multiple stations send all that data up to a server, the location of lightning strikes can be calculated, even if they’re hundreds of miles away from any station.

Each station works by detecting a change in the local EM field caused by a lightning strike with either a large loop antenna or a smaller ferrite core antenna. These signals can be amplified and turned into usable data, time stamped, and sent out on the Internet. From there, it’s a simple time of flight calculation to precisely locate where lightning strikes.

The hardware is actually pretty simple, with based on an STM32F4 Discovery board. A controller includes an Ethernet port, GPS unit, LCD, and all the hardware associated with detecting lightning strikes.

If you’d like to see what’s possible with a huge network of lightning detectors connected to the Internet you can check out LightningMaps for a look at what’s possible.

Thanks [Sean] for sending this in.

Tetris Duel With The Raspberry Pi

June 29, 2014 by 8 Comments

Tetris Duel

Building a multiplayer network game with multiple Raspberry Pis can be very difficult. Doing it in assembly is outright insane! This is exactly what a group of first year students at Imperial College London did; they created a network based multiplayer Tetris game for the Raspberry Pi.

[Han], [Piotr], [Michal], and [Utsav] have created this entire game from bare metal assembly, and it only consists of 4000 lines of code! The code is well documented, so be sure to look through their Github repository. This project is a great reference for those looking to learn bare metal assembly and networking. They even chose to use the old NES controllers, a very nice touch. While we have featured what seems like a million different Tetris games in the past, this is the first multiplayer version. See Tetris Duel in action in the video after the break!

This is a shout-out to all of you students out there. Take the time to create quality documentation for your class project, and upload it to the internet. Not only is it a great resume boost, but it could very well end up on Hackaday!

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Hackaday Links: June 29, 2014

June 29, 2014 by 10 Comments

hackaday-links-chain

Ever see a really cool build on YouTube with no build details at all? Frustrating, right? That’s us with the NES Keytar covering the Game of Thrones theme. He’s using a Raspi with the sound chip in the NES to do live chiptunes. Freakin’ awesome. There’s also the ST:TNG theme as well.

A few years ago the folks at Oculus had an idea – because of cellphones, small, high resolution displays are really cheap, so why not make VR goggles? At Google IO this week someone figured out everyone already has a cellphone, so just wrap it in some cardboard and call it a set of VR goggles. You can get a kit here, but the only difficult to source components are the lenses.

What happens when you put liquid nitrogen under a vacuum? Well, it should evaporate more, get colder, and freeze. Then it breaks up into solid nitrogen snow. No idea what you would do with this, but there ‘ya go. Oh, [NC], we’re going to need a writeup of that LN2 generator.

About a month ago, the House4Hack hackerspace in South Africa told us of their plans to bring a glider down from 20km above the Earth. They finally launched it, The CAA only allowed them to glide back from 6km (20,000 feet), but even from there the foam glider hit 230kph (124 knots). That’s a little impressive for a foam FPV platform, and we’re betting something with a larger wingspan would probably break a spar or something. Shout out to HABEX.

All the electronic dice projects we’ve seen have one thing in common: they’re not cubes. Thus uberdice. It’s six nine-pixel displays on the faces of a cube, powered by a battery, and controlled by an accelerometer. Yes, it is by far the most complicated die ever made, but it does look cool.

Simple Touch Controller Frees Up USB Port

June 29, 2014 by 6 Comments

touch screen demonstration using text

[typ.o] was working on a Raspberry Pi project and found himself running short on USB ports. The project required a touch screen interface, which takes up one of the ports. Since he was only using the screen in text mode, he decided to ditch the original USB controller and make his own.

The ever popular Attiny85 is deployed to handle the task, and is interfaced between the resistive touch panel and the Raspberry pi, using only three pins from the GPIO port. The Attiny85 runs off the 3 volt supply from the raspi, so no level shifter is needed, helping to keep his board super simple.

The calibration and calculation of the touched character location is done by a Python script running on the raspi. [typ.o] is a fan of the KISS principle, and it shows. Be sure to check out his site for all source code, schematics and a video demonstrating this simple but effective solution.

Counting Really, Really Fast With An FPGA

June 29, 2014 by 26 Comments

fast

During one of [Michael]’s many forum lurking sessions, he came across a discussion about frequency counting on a CPLD. He wondered if he could do the same on an FPGA, and how hard it would be to count high clock rates. As it turns out, it’s pretty hard with a naive solution. Being a bit more clever turns the task into a cakewalk, with a low-end FPGA being able to count clocks over 500 MHz.

The simplest solution for counting a clock would be to count a clock for a second with a huge, 30-bit counter. This is a terrible idea: long counters have a lot of propagation delays. Also, any sampling would have to run at least twice as fast as the input signal – not a great idea if you’re counting really fast clocks.

The solution is to have the input signal drive a very small counter – only five bits – and sample the counter using a slower clock on board the FPGA. [Michael] used a 5-bit Gray code, getting rid of the problem of the ‘11111’ to ‘00000’ rollover of a normal binary counter.

Because [Michael] is using a 5 bit clock with 31 edges sampled at 32 MHz, he can theoretically sample a 992 MHz clock. There isn’t a chance in hell of the Spartan 6 on his Papilio Pro board ever being able to measure that, but he is able to measure a 500 MHz clock, something that would be impossible without his clever bit of code.