Gadget Master

A common complaint shared by electronics engineers is that they run out of output lines when programming. Many projects need lots of drive lines and if one needs more than around eight, it may be wise to jump to another microcontroller.

This 89C51 PABX project is basically an eight line intercom from which you can call one to eight numbers.

Michael Seppanean shows us how to use a Basic Stamp microcontroller combined with a Park Zone Stoplight and a hacked Epsom printer to make a pumpkin pop up automatically when a visitor comes to the door.

David Fowler writes:

"This is the first in a series of articles about generating sound with an Arduino."

David Fowler writes:

"This is the second in a series of articles about generating sound with an Arduino. The first article covered the various methods available for sound generation with an Arduino."

This is the third in a series of articles about generating sound with an Arduino.

David writes:

"Often when working on microcontroller projects you need a background function to run at regular intervals. This is often done by setting up a hardware timer to generate an interrupt. The interrupt triggers an Interrupt Service Routine (ISR) to handle the periodic interrupt."

uCHobby does an instruction MindBite video about Digital Multimeters (DMM).

How high can you go? That's a question that model rocket enthusiast Jerry Baumeister wanted an answer to. Cheap enough to be used in even "risky" launches, Jerry's battery-powered device features a circuit designed around a Flash microcontroller that performs an analog-to-digital conversion of the voltage produced by an absolute pressure transducer. Altitude and operational data is then output to two LEDs. Since the output is in A/D units, Jerry just has to do a quick mathematical conversion and he's flying high. Or at least he knows if his rockets are.

DAC is short for Digital to Analog Converter. In this article we play around the code Michael Smith created for a PWM based DAC.

Looking for cool way of wowing that special someone on Valentines Day? Build her a flashing heart made from LEDs driven by a programmable microcontroller. Les' gadget is simple to build and made from easily-obtainable parts. The unique thing about this design is the LEDs are in an X-Y matrix so each LED is addressable. This allows an unlimited combination of displayed patterns for the heart. Source code and schematics are all available here and if you're not into hand wiring, even the PCB can be had for a small fee. Diamonds may be a girl's best friend but gadgets are forever.

Looking for a new way to make your business card stand out from the pack? Imagine the expression on a potential contact's face when you hand them this.

From the extremely well-titled Evil Mad Scientist site, comes a unique - not to mention fully functional - twist on the good old business card.

• Lego Mindstorms NXT 2.0
• Flavio plugs into smart extension sockets

Physical Computing - Final Project - Max MSP Controller from Ryan Raffa on Vimeo.

Over the last several weeks, students from the University of Texas at Austin have stepped up to the challenge of finding innovative ways to create a practical application using Texas Instruments' (TI) ARM cortex-A8 processor, also known as the BeagleBoard. You now have the opportunity to check out their designs and vote for your favorite!  There are many great designs.  So if you can't decide, you might consider the application's design complexity, the potential market demand or if the application is truly inspiring.

"This device turns my bedroom ceiling light on or off when I whistle a steady tone. It lets me turn on the light before getting up in the morning, to help myself wake up. It also lets me read in bed at night and then turn off the light without getting up. (The project was inspired when I read Atlas Shrugged a few months ago and couldn't put it down. I liked the vehement anti-socialist arguments and the fact that the ideal man in the book is a tall electrical engineer. Both things are true.) Some people might suggest that buying a bedside lamp would accomplish the same thing as this project, but I don't listen to those people. Also, this method lets me control a brighter light and costs slightly less."

The Raspberry Pi Foundation, which intends to sell its educational computers directly, auctioned 10 of its beta production board on eBay.