Build It

It’s the middle of the night, when suddenly you’re jarred awake by your ringing phone. It must be urgent, so you can’t waste time—or worse, miss the call—fumbling around trying to find the receiver. Instead, simply touch your hand to the top of your bedside table to answer the speakerphone. The secret is a stud finder (stuffed into the drawer of the nightstand). With a few modifications, it can sense when your hand is near it and activate a switch connected to your landline.

You're late for work. As you hustle out the front door, the furthest thing from your mind is the afternoon's dentist appointment that you'd scheduled last week. You'd have probably forgotten all about it — if you hadn't thought ahead by programming a home-built device to give you a voice reminder as you pass it on your way out.

Here's a handy carrying case for your movie reels. Made from 6" self-locking stovepipe, it stands 17 ½" high and accommodates 24 ordinary 200-foot reels.

After compressing the pipe until it just suited the 5 ¼" diameter of the reels, I cut it lengthwise into halves. Then I hinged the parts together, drilling the metal and using rivets to attach the hinges. On the other joint, I installed two suitcase catches, locating these to take care of the overlap.

When you're a performance artist, creating the right ambience in your show is everything. It all starts with lighting. So two years ago, my partner and I decided to build a lamp that would capture the aquatic theme of a show that our company, Radiohole, was putting on. We wanted to make a lightbulb look like it was submerged in water, so we used mineral oil, a liquid that's clear and nonconductive (we spilled a lot of oil before finally hitting on a fixture that was both portable and leakproof).

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.

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:

As you huddle inside your home this winter cursing the gloomy darkness, remember that you’re not alone: The season has an even worse effect on your plants. Many common houseplants need far more hours of light than they get naturally in the middle of February, especially if they don’t have direct exposure to a sunlit window. Although the incandescent and fluorescent bulbs most people have in their homes will keep plants alive, they don’t emit light that’s within the temperature range necessary for optimal, or even adequate, foliage growth in light-hungry plants.

Every AVR programmer worth her weight in ATmegas knows about the AVR Butterfly--a ridiculously low cost ATmega169 demonstration and evaluation kit. Lamenting the lack of such a kit for the ATmega168 drove me to design my own demo/eval kit for the Arduino microcontroller family.

No matter your poison -- coffee, tea, hot chocolate, sake -- take a gulp too soon out of the pot and chances are good that you'll burn your mouth. But build this Smart Coaster and you'll always know when it's safe to sip.

According to my thermometer, common coffee brewers produce a cup of perfect coffee that is positively molten to the tongue, at 160ºF. Even as this marvelous beverage fills your room-temperature cup, temps can still reach a blistering 137.1ºF. Finally, after a couple of minutes cooling, your coffee is safe to drink, at a lukewarm 116.5ºF.

So you've lost your eyeglass case. Yes, again. Gets frustrating, doesn't it? Stop wasting time searching for stuff -- build a device that emits signals you can see and hear, so you can find what you're looking for instantly. Attach remote-control car receivers to any items you frequently misplace, and put the cars' transmitters in a control box that can activate the receivers' lights and sound signals. Then when one of the items goes missing, press the corresponding button on the box, and you'll have it back in no time. Or at least until the next time you need it.