PWM On The Stellaris Launchpad

October 31, 2012 by Brian Benchoff 20 Comments

[Joonas] has been following TI’s ‘getting started’ tutorials for their new Stellaris Launchpad. Everything had been going swimmingly until [Joonas] reached the fourth tutorial on interrupts. To the ire of LEDs the world over, implementing PWM on the new Stellaris Launchpad is a somewhat difficult task. After banging his head against the documentation for hours, [Joonas] finally cracked his PWM problem and decided to share his discoveries with the world.

The Stellaris has a PWM mode for its six hardware timers, but unfortunately there are no PWM units on the chip. Solving this problem required making two 16-bit timers out of a single 32-bit one. This allowed [Joonas] to specify a ‘load’ and ‘match’ value.

After coding this up, [Joonas] discovered the PWM timer only works on two of the Launchpad’s pins. Hours of Googling later, he had real PWM on his Stellaris Launchpad.

Given the amount of time [Joonas] spent on this problem, we’re glad to help all the other frustrated Stellaris tinkerers out there by sharing this.

Myst Book Plays Myst, Doesn’t Transport You To Other Ages

October 30, 2012 by Brian Benchoff 58 Comments

We shouldn’t have to remind you, but back in the early 90s one of the most popular computer games was Myst. Despite having the gameplay of a PowerPoint presentation, Myst went on to become one of the best-selling video games of all time and the killer app that made a CD-ROM drive a necessity rather than a luxury. [riumplus] loves Myst, and after 6 long years he’s finally completed his homage to his favorite game. It’s a replica of the in-game Myst book that is able to play every game in the Myst-iverse.

The build started off by searching for the same book used as a model for the book object in Myst. It’s a 135-year-old edition of Harper’s New Monthly Magazine, Volume LIV, Issue 312 from 1877. In keeping with the in-game assets, [riumplus] made dies for the spine and cover, embossed the word ‘MYST’ on the book, and filled these letters with 24-carat gold paint.

Inside the newly hollowed-out book [rium] added a very small x86 motherboard running Windows XP on a 32 Gig Compact Flash card. This tiny computer is able to run every Myst game ever made on a very nice touchscreen display.

It’s a work of art in our humble opinion, and a fitting tribute to the last great hurrah of the adventure game genre. After the break you can see [rium] interacting with his book, or just check out the build pics on [rium]’s Google+ page.

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DIY Pick And Place Builds Boards, Is Awesome

October 29, 2012 by Brian Benchoff 12 Comments

In what can probably be attributed to the pains of placing a lot of SMD components, [gravelrash] built his own home-made pick and place machine.

Instead of being frustrated with tweezers, stereo microscopes, and having an inordinate amount of concentration, [gravelrash] built a pick and place machine from a Chinese CNC router. The build doesn’t use automated feeders for its reels of parts. Instead,[gravelrash] picked up five manual feeders from eBay, allowing his pick and place to hold 25 different reels of components.

There is, of course, a vacuum pump for sucking up SMD parts and a two-axis gantry capable of moving components from reel to board. The software is Mach3, a program normally used with spinning cutters to mill away wood, metal and plastic. [gravelrash] replaced this motor with a few vacuum controlled needles to pick up, move, and drop components onto the board.

While the build may not be as fast as some other pick and place machines we’ve seen, it’s almost as fast as hand-placing components with the added bonus of not tearing your hair out over very tiny parts.

Tip ‘o the hat to [Alexander] for sending this one in.

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Bora Board Teaches Binary Hardware

October 29, 2012 by Brian Benchoff 7 Comments

If you’re just starting out in your quest to build really cool electronic devices, you’ll find a ton of options ready for the beginner. The Arduino makes toggling pins dead simple, and the Raspi brings the wonders of blinking a LED from the command line down from the gods and into the hands of the common man. These are all software platforms, though, and if you want to learn digital logic with hardware the best option is still a drawer full of 7400-series logic chips.

[Colin O’Flynn] hopes to change this with a beginners board for digital logic hardware design. It’s called the BORA, or Binary explORer boArd, and brings digital logic to a convenient package that is far less frustrating than a breadboard full of logic chips.

The BORA is based around a CPLD – a cousin of the FPGA-powered devices we see from time to time – that allows any student of digital logic to program the device and fill macrocells with NANDs, NORs, and ANDs.

The Xilinx device used in the BORA has about 1600 gates that can be programmed; more than enough to complete all the projects in the online lectures [Colin] has put together. You can check out the documentation for the BORA over on the official site, and the demo video after the break.

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OpenPLC, For Industrial Automation To Halloween Displays

October 27, 2012 by Brian Benchoff 27 Comments

Stepping out onto just about any factory floor you’ll find complex automatons building anything and everything imaginable. These machines need to be controlled somehow and before the age of computers these manufacturing robots were controlled with relays wired together to produce a multitude of actions. Relays, no matter how reliable and bulletproof the are, can’t be programmed without rewiring the entire machine. Now, factories have programmable logic controllers to take care of their automation tasks.

[Thiago] built his own programmable logic controller and released it as open hardware.Included in the OpenPLC are four 24V inputs, four 24V outputs (two with PWM), 0-10V analog inputs, and USB, SPI, and I2C for programming and expansion.

If you’re building anything from an industrial machine in your garage, or simply want really awesome Halloween (or Christmas) decorations, the OpenPLC can take care of driving all the solenoids, motors, and actuators needed. With the extendable I2C and SPI busses, it’s possible to add a plethora of sensors to bring a project to life.

The OpenPLC is based on an ATMega328 and is compatible with Arduino code. There are a few extension boards for digital and analog IO, as well as Ethernet.

Fixing A First Generation GuruPlug’s Cooling Problems

October 25, 2012 by Mike Szczys 6 Comments

[Doragasu] had been using a hacked Xbox as his file server but upgraded to a single board Linux device when the GuruPlug was released. Unfortunately the first run of these devices had an overheating issue, which resulted in reboots even at moderate CPU load. The design was changed from a passively cooled heat sink to an internal fan, but that didn’t really help those who already had one of the early models. Above is [Doragasu’s] method of cooling down the overheating computer.

The original sink — which was really just a fin-less metal plate — was removed and replaced with a proper heat sink. This makes contact with the ARM, RAM, and Ethernet chips. They were all coated with thermal compound before installation and a silent fan was added to help whisk away the heat. This still fits inside of the original case, but to make way he did remove the original power source and cut a hole to allow for air movement.

The post also details an external LCD screen used to display system information. It’s along the same lines as this USB LCD screen project which inspired him to send us a link to the project.

Graphing The Efficiencies Of LED Light Strips

October 23, 2012 by Brian Benchoff 35 Comments

After adding a few LED light strips above his desk, [Bogdan] was impressed with the results. They’re bright, look awesome, and exude a hacker aesthetic. Wanting to expand his LED strip installation, [Bogdan] decided to see if these inexpensive LED strips were actually less expensive in the long run than regular incandescent bulbs. The results were surprising, and we’ve got to give [Bogdan] a hand for his testing methodology.

[Bogdan]’s test rig consists of a 15 cm piece of the LED strip left over from his previous installation. A Taos TSL2550 ambient light sensor is installed in a light-proof box along with the LED strip, and an AVR microcontroller writes the light level from the sensor and an ADC count (to get the current draw) of the rig every 6 hours.

After 700 hours, [Bogdan]’s testing rig shows some surprising results. The light level has decreased about 12%, meaning the efficiency of his LED strip is decreasing. As for projecting when his LEDs will reach the end of their useful life, [Bogdan] predicts after 2200 hours (about 3 months), the LED strip will have dropped to 70% of their original brightness.

Comparing his LED strip against traditional incandescent bulbs – including the price paid for the LED strip, the cost of powering both the bulb and the strip, the cost of the power supply, and the time involved in changing out a LED strip, [Bogdan] calculates it will take 2800 hours before cheap LEDs are a cost-effective replacement for bulbs. With a useful life 600 hours less than that, [Bogdan] figures replacing your workshop lighting with LED strips – inexpensive though they are – isn’t an efficient way to spend money.

Of course with any study in the efficiency of new technology there are bound to be some conflating factors. We’re thinking [Bogdan] did a pretty good job at gauging the efficiency of LED strips here, but we would like to see some data from some more expensive and hopefully more efficient LED strips.