how-to

912 Articles

Hardware hacking how-tos

Switched Mode Power Supply Repair Guide

February 6, 2011 by 46 Comments

switched_mode_power_supply_repaiir

[Erich] spotted a broken DVD recorder at a local amateur radio meeting and decided to see if he could restore it to working order. While he was fortunate enough that someone labeled it as having a bad power supply, things aren’t always that easy. He gives a broad explanation as to how switched mode power supplies work as well as discusses some of the reasons these devices tend to fail. He identifies a few common components and areas that one should check while diagnosing a non-functioning power supply. While obvious bulging capacitors are easily identifiable, he discusses the need for an ESR meter and uses a kit-built model to test capacitors that do not have any visual signs of damage. While some of his walkthrough might be basic knowledge for readers who have experience in recapping circuit boards, it serves as a nice guide for those who are new to the world of electronics troubleshooting and repair.

How To Build A Ping-pong Ball Display

January 31, 2011 by 41 Comments

If you’ve been lusting after your own glowing display we’re here to help by sharing some simple building techniques that will result in an interesting project like the one you see above. This is a super-accurate clock That uses ping-pong balls as diffusers for LEDs, but with a little know-how you can turn this into a full marquee display. Join me after break where I’ll share the details of the project and give you everything you need to know to build your own.

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Intro To Circuit Bending

January 11, 2011 by 54 Comments

Electronic musical instruments are a lot of fun for a hacker because, with a small palette of tools, know-how and curiosity, they are easily modified. As with any hack, there is always the chance that the subject will be ruined, so it’s not necessarily worth the risk to muck about inside your thousand-dollar pro synthesizer. Luckily for all of us, there are shovel-fulls of old electronic musical toys littering the curbs and second-hand shops of the world. These fun little devices provide ample opportunity to get familiar with audio electronics and circuit bending techniques.

A note on definitions: the term “circuit bending” can be synonymous with “hardware hacking” in the world of audio electronics, and we have seen some debate as to which term is better suited to a given project. We welcome you to share your viewpoints in the comments.

Keep reading to get started.
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Beginner Concepts: Powering Your Projects

November 20, 2010 by 44 Comments

Powering your gadgets generally seems like a necessary evil. To help with this [Felipe La Rotta] made a really nice bench power supply using a PC power supply and a LM317 adjustable voltage regulator. PC power supplies are an example of a switched power supply(more on that later).  The LM317 is a type of linear voltage regulator that allows for adjusting the output voltage by varying some resistors. Whats the best way to power your circuits? well that depends…

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AVR Programming 04: Writing Code, Etc.

November 19, 2010 by 24 Comments

Welcome back to this fourth and final installment of the series. The first three parts should have been enough to get you off the ground, but a few more learning examples wouldn’t hurt. It’s also a good time to discuss some of the other things these little chips can do. Join me after the break to:

  • Expand the sample code, adding features to our simple program while I challenge you to write the code yourself.
  • Discuss AVR fuse bits, how to use them, and what to watch out for
  • Touch on some of the peripherals you’ll come across in these chips

As a grand flourish to the series, I’ve used the example hardware from this final part to build a bicycle tail light. Hopefully this will inspire you to create something much more clever.

Series roadmap:

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AVR Programming 03: Reading And Compiling Code

November 5, 2010 by 41 Comments

In the last installment of our tutorial series we built a simple circuit on a breadboard and programmed an ATmega168 to make it run. That proves that you know how to follow directions, but the eureka moments of doing everything yourself are on the way. This time around you will get down and dirty with the datasheet, learning where each line of the sample code came from, and give your recently installed compiler a test drive. We will:

  • Talk about bitwise operators and how they work when coding for microcontrollers
  • Discuss C code shorthand
  • Review the sample code from Part 2 and talk about what each line of code does
  • Learn to compile code

If this is the first you’ve heard about our AVR Programming series, head back to Part 1 and start from the beginning. Otherwise, take a deep breath and we’ll being after the break.

Series roadmap:

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70 LED Matrix In A Jack-o-lantern

October 26, 2010 by 23 Comments

What takes eight hours to solder and uses more shrink tubing that you thought imaginable? An LED matrix installed in a real pumpkin. When I mentioned that we’d like the LED pumpkin in last Friday’s post scaled up to a full LED matrix I had no idea it would be me doing the work. But [Caleb] and I thought it might be just the thing to present for the hacker’s favorite holiday.

Installed in the autumn vegetable is a marquee made from a 5×14 matrix of light emitting diodes. I spaced them by printing out a grid on the computer, taping it to the pumpkin, and drilling 70 holes in the front of the thing. The real trouble came when inserting all of the LEDs from the inside; each of them has four wires soldered to it, creating a net of black wiring. Above you can see it turned out great. This is a shot of it scrolling the message HAPPY HALLOWEEN.

Join us after the break for video of this prop. But we’re not just sharing the finished product. I’ll take you through the build process. Along the way you’ll learn the design considerations that go into an LED matrix and how you can use these techniques to build your own in any size and configuration you desire.

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