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.

DIY Spot Welder Makes Metalwork Easy

October 31, 2012 by Brian Benchoff 62 Comments

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

October 31, 2012 by Jeremy Cook 2 Comments

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.

[youtube http://www.youtube.com/watch?v=PtaxgfQZSm4%5D