$25 Coupon Code For Texas Instruments Store

ti-25-buck-coupon

If you’ve been coveting a piece of Texas Instruments hardware you should put in an order before September 30th. A coupon code for $25 off a purchase was posted to the Stellaris ARM Community forums and it should work until that date. Above is the overview of an order placed yesterday for two Tiva Launchpads (apparently TI has rebranded the Stellaris chips as Tiva for some odd reason). After applying the coupon code “National-1yr” the total price of [BravoV’s] order is just under one dollar (including shipping). The coupon code can be entered into a box on the right hand column of step #3 (payment) when placing an order.

UPDATE: There are now multiple comments reporting that the coupon code no longer works.

We’re pretty sure you can use this coupon code on anything in the TI store. But if you don’t have a Stellaris/Tiva Launchpad yet we highly recommend getting one. We picked ours up about a year ago. It’s a great way to try your hand at ARM programming. We have had some issues with how the breakout headers are organized — there’s some gotchas with multiple pins being connected (read the last five paragraphs of the project write up linked in this post for more). But for the price and ease of programming this will get you up and coding in no time. If you need some ideas of what to do with the board look at our posts tagged as “Stellaris”.

[Thanks Vlad]

Stewart Platform Reinvents The Wheel So You Don’t Have To

StewartPlatform

[Dan Royer] has noticed that most university projects involving a Stewart platform spend more time building a platform than on the project itself. He hopes to build a standard platform universities can use as the basis for other projects.

Stewart platforms are six degree of freedom platforms often seen hefting flight simulators or telescopes. The layout of the actuators allows movements in X,Y,and Z as well as pitch, roll and yaw. While large platforms often use hydraulic systems to accelerate heavy loads quickly. [Dan] is looking at a smaller scale system. His platform is built of laser cut wood and uses six steppers to control motion.

One of the harder parts in designing a platform such as this is creating a mechanical system that is strong, precise, and smooth. With so many linkages, it’s easy to see how binding joints could bring the entire thing to a grinding halt. [Dan] is currently using RC helicopter ball joints, but he’s on the lookout for something even smoother.

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Revenge Of The Glueless Stool And A New Folding Chair

glueless stool

[Vincent] is at it again, with the final iteration of his glueless stool and a new project.

As many of you commented on the original post, three legs might not be enough. He might have taken note, as the final design contains not 3, not 4, but five legs. After the break we have a clip of it being used, and it looks quite sturdy!

But is that it? Is [Vincent] done with innovative wood furniture? Nope. Not since his wife came up with a challenge to create a practical, foldable, and especially, not ugly — chair. He began by researching the dry subject of chairs and determined the approximate popliteal height that his chair should provide. Keeping with the theme, he wanted this chair to be cut from a single piece of wood, just like the stool. A few sketches later and he had a basic design ready, still glueless, but unfortunately this time requiring hinges. After a few hiccups in his CNC program, he had a working foldable chair, but our guess is it’s not quite the final design.

Just like last time, all the files are freely available from his Github, so if you happen to have a CNC router, or maybe a laser cutter, you can make your own!

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Team Van Gogh Uses OpenXC To Create Art From Your Drive

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In this video, [Joe Grand] takes us through [Team Van Gogh’s] entry in the OpenXC hackathon event. In what could possibly be the greatest road trip in history, [Joe Grand, Ben Krasnow, TechNinja, and Super Awesome Sylvia] all pile into a car. With them they bring a host of dev boards, wires, a CB Radio, and of course Sylvia’s WaterColorBot.

As their name implies, [Team Van Gogh] took a more artistic approach to the challenge than other teams.  OpenXC steering, gear shift, accelerator and brake data is sent through a ChipKit to an RS-232 link into [TechNinja’s] laptop. The laptop translates the data into commands for the WaterColorBot. With this system, a simple Sunday drive can become abstract art.

The team also showed the concept of what could be done if OpenXC was extended to send data back to the vehicle – something Ford doesn’t support. Their example works when a phone call comes in by using the system to lower the volume on a CB radio standing in for car’s Bluetooth system.

Most of this challenge was completed with simulated data from the OpenXC vehicle interface. The team only had a few minutes to work the bugs out in a real vehicle. However, they proved their concepts well enough to win the grand prize.

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Aux-in On A 30 Year Old Boombox

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[Michael] just sent us this nice example of some good ol’ fashioned radio hacking.

He originally received the radio from his grandmother, and while he doesn’t listen to the radio much, he felt he couldn’t just let it go to waste. So like any good hacker he cracked open the case and took a look inside.

The beauty with radios from the 80’s is the simplicity of it all. They typically have single layer PCBs and nice big components which makes it so much easier to tinker with.

He used a bench power supply to bypass the main transformer for safety’s sake, and began probing the various points. The cassettes audio output was the easiest to find, but unfortunately it required the play button to be activated. Not wanting to lose functionality (or have an annoying rattling cassette mechanism), he continued probing and eventually found similar wires coming from the radio part of the PCB. Upon further probing he discovered he could trick the radio band button so that the radio would be off, but the output could still be used. After that it was just a matter of wiring, soldering, and adding an auxiliary plug to the case.

We’ve covered lots of auxiliary port hacks in the past, but this one is a great example of saving old technology from the dump.

[Thanks Michael!]

An Open Source Hardware Modchip

OSHW XenoGC Clone

Many Hackaday readers might remember the days of buying modchips from somewhat questionable sources. These little devices connect to a gaming system to circumvent security measures, allowing you to run homebrew games (and pirated games, but lets not focus on that). [Guillermo] built an open source hardware Gamecube modchip based on the XenoGC.

The XenoGC was a popular modchip back in the Gamecube days, and its source was released in a forum post. A Wiki page explains how to build a clone of the device based on an ATtiny2313.  Most modchips were closed source, but this project lets you look at how they work. You can browse the XenoGC source on Google Code to learn more about the exploit itself. You’ll find the AVR code, which manipulates the DVD drive over a serial interface, in the XenoAT folder.

[Guillermo]’s hardware is available from OSHPark, so you can easily order boards. He’s also hosted the design files on Github. With one in hand, you can start building homebrew for the Gamecube, which can probably be picked up for around $25 nowadays.

Explaining The Low Level Stuff You Don’t Know About ARM Programming

Most of us don’t realize how spoiled we are with the different development environments available on the internet. If someone wants to start a blank project on a new [ARM/DSP/…] platform, he usually fires up the dedicated Integrated Development Environment (IDE) and starts coding a C/C++ program. However, there are many initialization routines and scripts required with your program before it can run correctly. In his great article, [Andrew] explains to us what these are by starting a blank project without using any IDE.

As you can see in the above picture, [Andrew]’s project is made around an Atmel SAM4E microcontroller. The chosen toolchain is the arm-none-eabi-gcc from GNU Tools for ARM Embedded Processors. The first part of the article starts with a simplified explanation on how/why your code and variables are split into different memory sections (.bss, .data, .rodata, .text), then [Andrew] details how the linker script will put these sections at different physical addresses depending on your microcontroller’s memory layout. He also shows us how to take care of the stack placement, vector table, variable (non)initialization, and C Runtime. For information, the latter is executed when your processor starts, it is in charge of setting up the stack pointer, initializing the RAM, setting up the standard library and calling the main().

A very nice introduction on the very low level routines running on most processors out there.