dave prochnow

Converting an Old Bike Into An All-Electric Cruiser

Add an electric motor to your beater for pedal-free cycling

If you've ever wanted to strap yourself into one of those modern electric rides from Currie Technologies, now's your chance. A veritable smörgåsbord of surplus motors, gears, and controls is now available from All Electronics. Don't worry about this selection being a bunch of mismatched DIY surplus junk, either. All of these electric vehicle components are genuine Currie Technologies parts.

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Stop! Who Goes There?

Detect motion with itty-bitty embedded PIR sensors

Would you like to reduce the size of your home security system? Like something on the order of magnitude of motion detectors that can fit on a postage stamp? These tiny rectangular sensors are actually powerful passive infrared (PIR) detectors that can be easily slipped into an area where their larger PIR brethren couldn't even dream of fitting.

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Resistance is NOT Futile

Make your own resistors with paper and pencil

Have you ever needed a low-value resistor for a low-voltage battery-powered circuit? Say, something in the range of 10-100 ohms? Finding this value of resistor can be difficult, if not impossible. In cases like this, you might be better off making your own resistor.

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B.Y.O.B. Robot

Build your own bot kit powered by Arduino

Flushed from the success of their first autonomous vehicle competition, SparkFun Electronics (SFE) is now reaching out to wannabe bot builders. Whether you couldn't travel to Colorado and participate in the big event, or you've just always wanted to build your own robot, this bot building tutorial will fill the bill.

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The Smallest OS in the West

An operating system so small, if you drop it on the carpet you might lose it

Are you torn between two lovers, thinking back lovingly to those simple days of disk-based operating systems that could fit on a 1.44MB disk but remaining steadfastly enamored of a graphical user interface (GUI)? Hold on, Romeo: you can rekindle those passions, and it's only 10MB away.

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The Fastest Boot in the West

A Linux OS build that'll boot your system's pants off

The countdown is on, my friends. The countdown to the fastest booting OS, that is.

Forget those operating system sloths, Mac OS X and Windows (any flavor). The gauntlet was thrown down when the first mainstream commercial fast-boot OS appeared on a small solid-state drive (SSD) that had been pruned to operate on an ASUS eeePC.

Granted, the fast seek times for data access with the SSD contributed to Xandros's (the eeePC OS) speedy boot time, but users became enamored with the quick, "less than one minute," access to their apps. Thus was born the race to the fastest boot time.

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For Easy Prototyping, Surf’s Up

These "surfboards" make surface-mount prototyping "boardacious," dude

If you've done a fair amount of electronics circuit building, then you probably dread prototyping. You know prototyping: that point where you take your "perfect" circuit design from paper and transfer it to an initial hardware mockup. Typically, you have three basic choices in this matter, each with its own problem.

Your first choice in circuit prototyping is to lay out your design on a modular breadboard. The strongest virtue of this choice is the elimination of soldering -- all connections are built into the breadboard. Unfortunately, breadboards are bulky and unable to handle surface-mount device (SMD) designs.

Following closely on the heels of breadboard prototyping, your second choice is perfboard layout. Once again, most perfboards are unable to accommodate SMD circuit designs. Plus, the point-to-point wiring needed for connecting the components can be a daunting task.

Which leads us to your final choice for circuit prototyping: custom printed circuit board (PCB) fabrication. Whether you roll your own PCB with DIY masks and etch kits, or hire a fab house to create a custom PCB, time will be your enemy. Fab houses can take upwards of one month for delivery of a finished board (unless you're willing to pay extra for faster service), and making your own PCB can be fraught with frustrating failures and delays which can take days to weeks to solve.

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Pennywise Solar Power

An eight-volt DC solar power plant that fits on a penny

No matter whether you felt that Earth Hour was a terrific conservation tactic or an overhyped PR stunt, energy on our planet is in peril. Our daily juice (be it electric, gasoline combustion, atomic, or carbon-based), has become a precious commodity with at least one guaranteed effect: to elicit an instantaneous hot-button opinion from just about everybody.

What can you do about it? Well, one great proactive demonstration would be to stop your regular consumption of dry-cell batteries. Yes, there are numerous substitutes, ranging from rechargeable varieties to alternative energy replacements, but each of these substitutions has a debit that few of us are willing to pay. You know, "costs" like always hunting for an outlet to power a battery recharging station, or getting rid of a clean, slim-line AA battery for a gargantuan solar-driven bat-winged monstrosity.

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How to Make an iPhone App: Part Three

You thought coding was hard; now it's time to get your app approved

In the previous two installments of this series, we labored through some ornery hardware wrangling and tested our mettle with some serious Objective-C coding, now it's time to deliver our app to the masses.

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How to Make an iPhone App: Part Two

Building a great app: that’s the objective, see?

The third and final installment in this series takes our App to market, err, the App Store.

In the first part of this series, we covered the "nuts and bolts" for assembling a workable iPhone app development platform. Now that our desktop is cluttered with a mess of cables, it's time to roll up our sleeves and start cobbling some code together.

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How to Make an iPhone App: Part One

Gain fame and fortune: become an iPhone app mogul

See part two on coding your App.

Love it or hate it, it's tough to argue about the success of the Apple App Store. While this venture might be a successful cash cow business model for Apple, how does business fare for the app developer? Pretty good, it turns out.

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Give Some Microcontroller Love

Say “I love you” with an “I Love ST” board

From the US PopSci team

Are you looking for a gift for that special someone, that will also have some great practical worth when it's dumped back in your lap on February 15th? The I Love ST microcontroller evaluation board combines touching sentiment with touch capacitance, all wrapped up in a cute little red heart-shaped PCB ringed with red LEDs.

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Dot • Watch

No hands, no numbers; it’s a clock you can count on

Trying to squeeze some new life out of the tried-and-true clock paradigm can be a frustrating design challenge. Likewise, creating a clock from the absolute minimal number of parts (e.g., no more than 6 components) can lead to some sleepless nights. Finally, trying to shoehorn everything into an itty-bitty space (roughly 2-x3-inches) and making it a portable, battery-powered clock can make even a seasoned project builder scream “Uncle!” Getting everything to work like, err, clockwork, priceless.

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Make a Guess Game

No microcontroller, no programming; just a handful of stock ICs—see if you can “guess” what comes next

OK, guess a number between 0 and 15. Wrong! Guess, again. No, I’m not the Amazing Kreskin, I’m just vying for numerical precognitive prediction superiority versus a formidable 74LS193/74LS85 tag team foe. Oh, sure, some of you might call it a game, but this project can be an amazing demonstration of just how much fun you can get from stock ICs.

Derived from a Forrest M. Mims, III project, our Make a Guess game adds a 7-segment LED display for helping you visual your numerical guess. Here’s how it works:

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A Really Tiny tinyCylon

Give your cybernetic “toaster” a new set of eyes

I first mentioned Dale Wheat’s tinyCylon kit during a post regarding the “new” SN76477 complex sound generator IC. In case you missed it, tinyCylon is a small kit that creates 10 different LED flashing patterns with 5 red LEDs, an Atmel ATtiny13 microcontroller, and a 4.5VDC battery pack. In other words it’s an LED blinky PCB—easy to assemble and easy to operate.

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