Racking Up Miles On A Bicycle Odometer

February 25, 2011 by Noah Dunker 27 Comments

[jonh] religiously tracks the miles he rides on his bicycle. When his odometer’s battery started getting low, he wanted a way to run the miles up to where they were before, since replacing the battery resets everything to zero. [jonh] used an Atmel microcontroller to run up the miles on his bike computer so he could pick right back up where he left off. There is definitely a Ferris Bueller’s Day Off joke in here somewhere.

The bike computer itself is designed to plug into a base that connects to a magnet-triggered reed relay. It uses a wheel-mounted magnet to count the number of revolutions made and thus the distance traveled. [jonh] hooked up a simple microcontroller-driven circuit to these connectors to trick the bike computer into thinking it was moving, and moving fast! Since he knew the number of miles he wanted to sandbag onto the odometer, he was able to program it to run up the proper amount of miles and then stop. There’s no source code listing for the project, but this shouldn’t be too hard to reproduce. He provides a pencil-drawn schematic for the connection to the cyclometer from the microcontroller. At the end, there’s also some sage advice for those of you who are interested in building a decent hardware hacking lab on the cheap.

Building A 555 Timer From Discrete Components

February 25, 2011 by Noah Dunker 18 Comments

The 555 Design Contest shook a whole bunch of really creative circuits out of the trees, hence the 555-heavy content lately. While not technically part of the contest, [esalazar] wanted to know what made the 555 tick, literally! He started working on the project in a circuit simulator, then ultimately ended up building the three main logic blocks inside the familiar timer on pieces of copper-clad board. He’d built a 555 using discrete components.

While this isn’t 100% compatible with the classic 555 IC, it covers the basics pretty well, and [esalazar] gets extra-credit points for embracing the hacker spirit of seeing for himself how stuff works while documenting it well and citing his references.

DIY PIC Development Board And Web Server

February 12, 2011 by Mike Nathan 16 Comments

websd

Inspired by a project featured here on Hack-a-Day, [arthurb] bought himself a PIC 24F and started experimenting once he learned the ins and outs of programming the chip. Using a breadboard and a nest of wires was fine for his first few projects, but as he advanced, he began to feel the need for a full-fledged development board. With a list of required features in mind he got to work, constructing a well thought out board as well as a handful of expansion boards that can be used for various other projects. His main development board includes Ethernet connectivity for use with his web server software, the ability to utilize an SD card for storage, and a USB port for programming. His expansion boards include a temperature sensor, a numeric touchpad, as well as a video output module. Overall it is a pretty impressive build, considering he had never programmed a PIC before starting this project. All of his boards are thoroughly documented, and he has included plenty of source code in hopes of helping other individuals just starting out in PIC programming.

You can see his web server in action here, but keep in mind that it is running off a PIC, so please be courteous in your usage.

Custom Enclosures Made Of Paper

February 5, 2011 by Kevin Dady 47 Comments

[Sivan Toledo] needed a enclosure for a unique sized electronic project, not finding what he needed in off the shelf solutions, he went to the next best thing, … Papier Mâché!

Using a mold made out of standard corrugated cardboard, he slowly built up layers made of magazine paper, and ordinary “white glue” diluted with water. After getting near the thickness wanted he switched over to typing / copy type paper for a nice clean outer surface. Ports were made in the usual fashion when dealing with soft or thin material, drill a smaller hole, going back with successively larger holes, and then follow up with an appropriate file, all while taking things slow along the way to prevent unwanted results. Finishing up with layers of paper carefully cut into strips to meet the circumferences / edges, along with the final outer surface to make it all even.

The end result is awesome as it stands, but we cant help but wonder what some sanding and paint would look like on a enclosure made like this, though any way you finish it, the idea comes down to custom enclosures that do not need special tools or materials to complete (on the cheap).

Thanks [Drone]

Double The Hertz, Double The Pleasure

November 24, 2010 by Joseph Thibodeau 41 Comments

[tinhead] has opened up a Tekway DST1102B oscilloscope and doubled its bandwidth to 200MHz, sharing his work in the eevblog forum. This is great news to anyone who is looking for a faster sampling rate but can’t afford the high-end models. Mind you, for a lot of us even these Hanteks and Tekways are hard to afford but there are more appropriate options for the ramen-dependent hacker.

In the hacking guide [tinhead] includes comprehensive information on the different scopes he originally considered (a Rigol, Atten and UniTrend) before settling on the Tekway, as well as links to regional distributors for the hackable scope. Good quality benchtop units are invaluable for development and troubleshooting, and it pays off to understand their inner workings. It’s heartwarming to know that even the tools of hacking can be hacked.

Beginner Concepts: Powering Your Projects

November 20, 2010 by Chris Nelson 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…

Continue reading “Beginner Concepts: Powering Your Projects” →

Beginner Concepts: LEDs And Laws

November 9, 2010 by Devlin Thyne 19 Comments

Adafruit has a new LED tutorial for people wanting to get started with electronics. It is full of useful diagrams, pictures, and quizzes to help make sure you are understanding the concepts. This is the real basic stuff here: LEDs, resistors, and the laws from Kirchhoff, and Ohm. It starts out explaining the parts of an LED. Then variations of LEDs: illumination versus indication, clear versus diffused, brightness, color, and size. The mass of the tutorial covers how and why an LED’s brightness can be changed by a resistor and why a resistor is needed to keep an LED from burning out. Such as how Kirchhoff’s Voltage Law works with Ohm’s Law to help you determine the proper resistor for an LED. If you found useful the other beginner concepts posts about Analog Circuits and Electronics basics from the Giz, you should find this tutorial to be useful.