Build the Alarm Autodialer
This device will detect and report several common failures with household systems, so you can deal with them while they are still easy to fix. It's inexpensive ($60 or less, depending on your parts collection), easy to build, and doesn't require any contracts with monitoring services.
Make the PLL Frequency Synthesizer with PIC Control
This project describes how to build a frequency synthesizer — a device which generates a stable waveform at a user-selected frequency. Frequency synthesizers are handy test instruments for digital circuits, and can also be used for audio signal generators or radio frequency mixing applications. This project is easy to build, easy to use, and a great way to learn more about how phase-locked loops work.
Bicycle Gear Position Indicator
Here’s a couple of simple circuits to tell you what gear your bicycle is in while you’re pedaling down the road. I usually check what gear I am in by looking down at the front and rear gears. I decided I needed a better way after I bought a good road bike with 30 (!) gear combinations (three gears in front and 10 in back).
Radio Locator Beacon For Flying Objects
Exclusive Online Article: The locator beacon weighs about an ounce with its 12-volt A23 alkaline battery, and could be made lighter with the use of surface-mount parts. It’s also simple and inexpensive, so you can afford to build another one if necessary.
Model Train Switch Control via PC or PIC
This is a project I wanted to do many years ago when I was spending a lot of time and money on my model railroad. I was disappointed by the big, clunky electrical controllers which operated the track switches, and I wanted to have something smaller and more elegant to do the job. A computer control system would have been ideal, but I never got around to designing one. Many years and several designs later, I have come up with two versions of the control system: one PC-based and one PIC-based...
PIC-based Motorcycle Gear Indicator
A while back, a friend of mine with a Suzuki Katana motorcycle sent me some plans he pulled off the Internet for circuits that would tell him what gear his motorcycle was in while he zipped down the highway. Since I’d helped him with some other electrical and electronic projects for his bike, he figured I could build one of these for him. I looked over the schematics he had found but wasn’t too impressed — most were for “strip gauges” which lit a different LED for each gear...
The Poor Man’s CNC Milling Machine
Wouldn’t you love to have a fancy computer-controlled drilling and milling machine so you could make whatever part you needed? Wouldn’t you love even more to have the money one of those machines cost? Well, I don’t have either, but I do have an occasional need to fabricate a simple part or drill a custom circuit board.
A Simple Digital Tachometer
I bought a used Nissan pickup truck a few years back that had absolutely no bells or whistles on it when it rolled off the assembly line. I wanted to make some “improvements” to the engine, and I wanted a tachometer to help assess the results (for better or worse). The add-on tachometers available in auto parts stores didn’t appeal to me, mostly because I knew I could make one myself if I put my mind to it. What I really wanted was a digital tachometer...