Homo ludens electronicus

My interest in electronics started when I was 12 years old, although I had built electric devices (lighting systems, flashlights, solenoids, even a motor) much earlier. At age 12 I started the real thing: Radios, sound effect generators, light games, etc. This obsession of building things led to a career in electronics, but also it has become my most interesting hobby. I regularly design and build things, and now I will share my better documented projects with you.

Each of the following links leads to a page giving constructional information (schematics, sometimes printed circuit layouts, and text) for an electronic project. You are welcome to use this information for educational purposes and for your own use, but please be honest enough not to make business with them. Any kind of commercial use must first be authorized.

12 Volt fluorescent lamp drivers: Three schematics of 12 V drivers for 2, 8 and 20 Watt, plus a lot of explanations about fluorescent tubes. Use the drivers for camping, emergency, boating, etc.

Active Hi-fi speakers: A pair of large three-way speakers with built-in active cross-over and expanded class-A amplifiers, exhibiting very high sound quality, while being neither hard to build, nor expensive. Schematic diagram, printed circuit board layout, and several photos are included.

13.8 Volt, 20 Ampere linear power supply: A semi-traditional power supply for communication equipment, using negative-rail regulation with grounded pass transistors in a configuration that gives some unique advantages.

13.8 Volt, 40 Ampere switching power supply: A heavy duty, highly efficient, small and lightweight power supply specially designed for use with communication equipment. This article was originally written for the QST magazine, and now it is re-published on-line. Includes text, schematic diagram, printed circuit board layout, and some photos.

Altimeter/Variometer for free  flying: A handheld instrument intended for the paraglider and hang glider pilot. Displays altitude above sea level, altitude above take off, climb and fall rates, flight time, maximum altitude. Software-calibrated, features a backlit LCD, internal rechargeable batteries and internal charge regulator. Uses a Basic Stamp II.

Solar panel regulator: A simple but good linear shunt voltage regulator for solar panels, that includes deep-discharge protection. This design is for 12V systems with panels delivering up to 7A, but it can be easily scaled for other sizes. I have built several of these regulators.

Another solar panel regulator: This is a switching shunt regulator which is very simple and reliable, but does not regulate as smoothly as the one above and has no deep-discharge protection. It was built for a yacht.

SWR meter for 1 to 1300 MHz: A very simple design, cheap to built, does not require adjustment and works well! Depending on specific components and construction technique used, the upper frequency limit will be somewhere between 150MHz and 5GHz!

DC-DC converters: Two converters are shown here. One powers a VCR or similar device from a car battery, while the other powers a model airplane glow plug from 12V.

Plant watering timer: It's time to automate the watering of your garden, balcony, or that azalea in your living room!

Room heating controller: Tired of mechanical thermostats that overshoot the set point and make you waste expensive energy? Here is a phase-control device that works well and is simple!

Transformers and coils: This is not a building project, but a short and concise lesson in how to design electromagnetic parts. It's much simpler than what you may expect!

40 meter SSB QRP transceiver: In 1987 I built this radio. It has been published in a national ham radio magazine, and now finally found its way into the web!

Mercury battery replacement: Many old cameras and other devices used mercury batteries, which are no longer available. Here is an analysis of the problem, and a few solutions.

An automatically tuned HF mobile antenna:  This elegant design covers the complete spectrum from 7 to 30 MHz at less than 1.3:1 SWR, is compact, very weatherproof, robust and has good performance. This article was first published in the QEX / Communication Quarterly magazine, and is now re-published online. The article is in five pages, with lots of photos, mechanical drawings, schematic diagram, PCB layout and software listing. Exact duplication is not for the faint of heart, but some of you may find individual parts and ideas useful for your own projects!

144MHz to 50MHz receive converter: A simple accessory for a satellite station, that allows using a 6 meter capable radio in conjunction with a typical S-band to 2 meter converter.

Controller for rotary film processor: If you want to develop your color film, and specially slides, at home, here is the machine you need!

Thermal design: A short course in keeping electronic parts adequately cool.

Small audio amplifiers: Making small, inexpensive, simple 1-Watt audio amplifiers that produce high quality sound.

FodTrack: My world-famous realtime satellite tracking system!

Let me know what kind of project you may be interested in. I may just have built it! Your request can trigger me to put the project on this page!

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