There’s nothing better than Guys’ Night, an evening of gaming or movies in my basement media room. The only trouble is when we (invariably) order pizza, because I can’t hear the doorbell from there. The solution: an inexpensive DIY digital surveillance system tied to Twitter.

Throw out your old wall clock. You’ll be bored with it the moment you’re finished assembling your own persistence-of-vision (POV) clock. Projects based on POV—the phenomenon by which your eye very briefly continues to see an image after it has disappeared—use a moving display to show what looks like a static image. But instead of featuring only a single fixed message, this model shows you the current time on a continuously updated rotating display.

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.

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.

It's hump day and I was looking for a quick, fun project to try out. So I figured I try something easy I found over at the Make Magazine blog earlier this week—a set of speakers made from paper cups and a pair of earbud headphones originally created by artist Dmitry Zagga (in no small amount of jest). The PaperCup speakers are based on the principle of a megaphone: Energy from sound waves from the earbuds would normally disperse in all directions. Instead, the cups focus the sound waves in a particular direction, making it louder for those in front.

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 71ºC. Even as this marvelous beverage fills your room-temperature cup, temps can still reach a blistering 58ºC. Finally, after a couple of minutes cooling, your coffee is safe to drink, at a lukewarm 47ºC.

An intrepid modder was given a sad, water-damaged MacBook and turned it into his own little Mac Pro Mini with a little know-how and a $US40 Mac Pro case knockoff. His MacBook's motherboard worked, but LCD, HDD, battery, memory, keyboard, and DVD drive were all busted. After replacing the HDD and memory, he set out to stuff his cheap-o case with the corpse of his MacBook.

Science Projects

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.

Want to add some robots to your Halloween party plans? Even better, how about some robot "bugs" dancing around the candy bowl? Then Boo, the light-loving bug bot, might be for you.

Al Gore and company have helped us to see that our planet is in peril. Lend a hand, make a toast, and help illuminate ways for saving Earth -- all at the same time! It's easy to do your part: recycle, refill, and recharge.

If you've ever wanted to learn how to hack a circuit's firmware, a great beginning point would be SparkFun Electronics. Many of the development, prototyping, and sensor products sold by SparkFun come equipped with a special programming interface. Even better, most of these products feature downloadable firmware. Therefore, with just a modest amount of effort, you can modify one of these products' firmware, reprogram the circuit, and create your own customized product.