Gadget Freak

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.

Take down the house with this gadget. William’s handheld controller provides the display of a monitored process deviation – but after hours it doubles as a card counter (In either case, the algorithm is identical). It works by adding or subtracting manually entered “event” counts to a common 8-bit counter register. The value is subtracted from a predefined mean to generate the error or variation around the mean. This error “index” selects a display state sequence, continuously scheduled in an LED display.

Looking to paint the town red (or his friends at any rate), Nathan Loden devised this simple device to detect if the paintballs are travelling at a safe speed. Consisting of sensor circuitry and a microcontroller with a three digit, seven segment display driver, it detects the presence or absence of a ball by measuring the amount of IR energy striking the sensor, causing a voltage swing detectable by the micro. A timer is set to overload if the number of instruction cycles exceeds the limit, indicating safe shooting.