PWM on the Stellaris Launchpad

[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.

DIY spot welder makes metalwork easy

At Hackaday, we’ve seen enclosures built out of just about every material. From wood, glass, epoxy resin, plastic, and even paper, all these different types of enclosures provide some interesting properties. Sometimes, though, you need an enclosure made out of metal and welding together steel cases isn’t exactly easy or cheap. [manekinen] came up with a really great solution to the problem of welding together sheet metal. It’s a very easy to build spot welder perfect for fabbing steel cases.

The core of the build is a transformer pulled from a Technics stereo amplifier. [manekinen] removed the stock secondary winding and rewound the transformer four turns of 35mm ² wire (about 2 AWG). This made the transformer put out 2.6 Volts a 1 kA – more than enough to weld 22 ga sheet.

For the control mechanism, [manekinen] put a limit switch on the electrode arm and wired that to a timer. A knob on the front of the welder allows him to vary the time the welder is on from 0 seconds to 4 seconds.

The results are fantastic – trying to rip apart a weld only results in the metal itself tearing; exactly what you want to see in a welder. It’s a great build made even more fantastic by the welder building its own enclosure.

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A Scary Pumpkin Pi


What do you get when you combine motion sensors , a Raspberry Pi, and a pumpkin? When it’s Haloween, a headless scarecrow with a light-up carved pumpkin in its lap! The execution of this hack is really great, and the resulting effect, as shown in the video after the break, should be extremely scary to any kids that come knocking.

One neat effect of this hack is that it uses X10 home automation modules to turn off the porch lights for an extra scary effect. After this, the jack-o-lantern lights up and says “help me!” If you’d like to duplicate, or build on this hack, instructions are provided as well as source code for everything on the page. While you’re there, be sure to poke around on [Insentricity] as there are quite a few other hacks available for your perusal! Don’t forget sure to send us any other Halloween hacks that you come up with.

Nyan Cat hat will be the hit of the party…. for about one minute

Seriously, this Nyan Cat hat is the only part needed for a fantastic Halloween costume. It looks pretty good in this still image, but we dare you to watch the clip of it in action (embedded after the break) without letting a beaming grin creep onto your face. Everyone’s going to just love this… until it starts to get really annoying.

When switched on, the iconic meme rotates around the headgear, bobbing its head and tail as she sings the song of her people. There are also stars made of white LEDs that twinkle very brightly in the process. The presentation is quite good, but even better is seeing the build process. Luckily [Ben Katz] posted a series of detailed articles during the adventure. The mechanism responsible for driving the cat around the hat was laser cut from acrylic. It includes a large gear with teeth on the inside, which is interface by a continuously rotating servo motor with a much smaller gear. The head and tail bobbing are purely mechanical, using the revolving motion to turn a spindle as the cat makes its way around the brim.

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DSO Quad contest has a quartet of cash prizes

Seeed Studios has launched a contest centered around the DSO Quad. In case you’re unfamiliar with the hardware, the DSO Quad is a low-cost standalone oscilloscope. It’s got four channels, two of which are analog, and includes an ARM Cortex-M3 processor as well as an FPGA. Why are we recapping the hardware with the contest announcement? Because the contest rules state that you are allowed to alter the hardware despite the fact that this is more of a software-focused event.

But what you really should know about are the cash prizes going to the winners. Rank in the top four and you’ll claim $3000, $1500, $800, and $300 in cold hard cash. But even if you don’t take one of the top spots everyone still wins. That’s because all entries are open source and will be found in Seeed’s DSO Quad forums.

If judging people is more your thing Seeed needs some help with that too. They’re looking for qualified judges and application details are includes at the bottom of the contest page.

[Thanks Petteri]

Halloween Props: Monster in a box

This furry Halloween decoration proves to be a simple build, but it’s still quite popular with the little ones. [Chris] had a Halloween party for a group of 2-5 year olds and this monster that peeks out of a box was a huge hit. The trick really isn’t in the complexity of the build, but in the interactivity.

The enclosure is just a shoe box which has been covered in synthetic black fur. The lid was hinged on the back, and a hobby servo with a bit of an extension on the arm is used to lift the front which reveals the monster’s paper eyes. Inside you’ll find an Arduino, breadboard, and battery pack. It’s not visible above, but a distance sensor on the front of the box is monitored by the Arduino. When it detects something in front of it the servo fires up and pops open the lid. The firmware includes a timer so that the monster waits a bit before taking its next peek at the party.