DIY - Do It Yourself Electronic Projects

The electronics as a hobby seems slowly but surely to die out. Why is that? The reason is probably that most of the gadgets that you ever will need - can nowadays be bought off-the-shelf! And most probably at a cheaper price than a homemade equivalent. And with least effort.

Almost everything is now microprocessor controlled - and there is a myriad of highly integrated application specific IC's that does the trick with minimal amount of discrete components. The ability to read an application note means that you can almost construct a useful circuit. The FUN of inventing things of your own is almost gone --- almost.


I never planned to publish any of this work, therefore I never produced much documentation to begin with. As you might know - an musician rarely writes down the music he already can play. Frankly speaking - since most of the projects were of the type "one-off", I seldom produced more than a hand-drawn and just barely readable schematic. However, I have tried my best in reconstructing and recovering the missing information to such a level, that it is possible for an intermediate or experienced hobbyist to successfully complete the projects. Please remember that most of the circuits were designed before microprocessors became a cost-effective way of building gadgets. Independent of this - most circuits are hopefully still today valuable construction projects.

The projects presented here are just a small fraction of the more simpler and hobby-friendly electronic circuits I have designed & built since I started my electronics as a hobby many, many years ago.


I have NOT included full instructions or printed circuit board designs. However, the designs are proven and really built, so the schematics should be reliable. Some projects have detailed instructions that will help during the construction - together with some pictures of the prototypes. Some might have a PCB-layout presented.

All circuits presented here are uniquely designed by me, the author, unless otherwise specified. I reserve all rights to all information presented on these pages. I am not knowingly violating any copyrights or patents - nor offending deliberately other people by presenting pictures, schematics, ideas and any other material as my own. The information presented here (on this and subsequent pages) may not be used commercially, published, copied, transferred or distributed in any way, without written permission from the author. However, you are only allowed to use the information presented here as the basis for your private non-commercial construction projects.

Power Supply and Motor Control Circuits

A high quality and lower powermains zero crossing ciruit. Features a very accurate mains zero crossing detection, fully isolated and low voltage safe output together with ultralow power consumption; worst case power dissipation is < 130mW.

A highly capable professional grade special purpose power supply that outputs +105 Volts DC at 500mA! This power supply can feed simultaneosuly 6 Neumann U-47 microphones. The power supply is foldback current limited, and can thus withstand constant short circuit without overheating. The output ripple is very low (<200uVpp).  This is a must for totally hum-less operation.

Pulse-width controlled DC-motor power controller with soft turn of and turn off. Good for any kind of DC-motor that should be started and turned off gradually. Maximum speed can be set as the direction of rotation. Uses just a few of "plain vanilla" components.

Amplifier & Audio Circuits

A powerful and ultra-small size audio power amplifier (can be built to about matchbox size - excluding the power supply). Uses a unique "double - bootstrap™" - technique that ensures full saturation of the complementary MOSFET stage without the need for additional supply voltages. Intended to be used with 8 ohm speakers.

A resistive dummy load for testing audio power amplifiers. Includes selectable resistance, a power level meter and an audio monitor function. Uses non-inductive power resistors and can dissipate 300W at 8 ohm and 600W at 4 and 16 ohm.

A professional quality sweepable 4-band single-channel audio equalizer. Few parts, yet excellent quality with high boost/cut ratios. Gives your bass or electric guitar - or any other monophonic line signal - the extra "punch". Schematic and parts indications available.

U-47 Neumann Condenser Refurbished Microphone

Instructions of how to refurbish or build a Neumann U47 condenser microphone. The birthday of these stunning and warm- sounding beauties was already in 1956! There is still a reamarkable number of these beauties in studios all around the world. It is almost impossible to find original (spare) parts, but luckily some companies make good copies, but at a "salty" price. Original tubes can be found from time to time. Drop me an email if you need one.

I designed a power supply for these microphones, since the original PSU was in a dangerous condition. The instructions ans a schematic diagram are also found on my site.

An "Oldie but Goldie" robust power audio amp, cheap to build since you will probably find the parts in your electronic junkyard. Not the best power amplifier for the ultimate purist, but a very simple, cheap and efficient one for the beginner, PCB layout available as well as complete instructions - but mainly in Finnish. This design of mine was published in the late 1979 in a local electronics magazine in Finland.

Simulators & Gaming Circuits

Realistic Traffic Light Simulator

Coming soon...

Simple Electronic Dice

Coming soon...

Animated Fortune Wheel

Coming soon...

Digital 1 Minute Timer

Coming soon...

Light & LED controllers

4-Channel Animated Dimmer

Coming soon...

Valentines' Day Animated LED-Heart

Coming soon...

Ultralow Frequency LED-beacon

Coming soon...

Alarm & Thermostat & Timekeeping circuits

Time-of-day Clock using Nixie-tubes

Coming soon...

Intruder alarm controller

Coming soon...

Water Level Alarm

Coming soon...

Fan Thermostat

Coming soon...

Telephone Circuits

Home Intercom Using Existing Telephones & Wiring

A simple but ingenius electronic circuit that turns all your household telephones and existing wiring into an intercom system - without disturbing the normal operation of the phones. Uses less than 30 easy-to-get components, including the power supply. This design won the 6th price in the Elector (UK) magazine reader's contest in 1995. Printed circuit boards might be available from time to time.

Coming soon...

Telephone Line Recording Interface

A device that plugs between any phone outlet and your Dictaphone (or tape recorder), turning it into a device that automatically records all incoming and outgoing calls. The device automatically discards all idle passages, as well ass all modem and fax traffic, if they happen to share the same phone line.

Coming soon...

Video & RF-circuits

Coming soon...