DIY Projects

DIY - Do It Yourself Projects


I never planned to publish any of this work, therefore I never produced much documentation, to begin with. Like a musician that rarely needs a music score for 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. Sometimes not even that...

I have tried my best in reconstructing and recovering the missing information to such a level that it should be possible for an intermediate or experienced hobbyist to successfully complete the projects.

Please note that most of the circuits were designed before microprocessors became a cost-effective way of building gadgets. Independent of this, most of the circuits are still valuable construction projects. Some of the designs were based on what components were available in the component junkyard at the time of the design.

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


Most of these projects don't include full instructions nor printed circuit board designs. However, all designs are proven and actually built, so the schematics should be reliable. Some projects have detailed instructions together with some pictures of the prototypes. Some might have a tentative PCB-layout shown.

Some designs contain lethal voltages and/or power levels. I cannot be kept responsible for any injuries you cause to yourself or other persons if not following my instructions and warnings.

All circuits presented here are designed by me unless otherwise specified. I reserve the rights to the information presented on this site. I am not knowingly violating any copyrights or patents - nor deliberately offending other people by presenting pictures, schematics, ideas and 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 me.

You are allowed to use the information presented here, as the basis for your private and non-commercial construction projects.

Electric Motor Speed Controller (ex. for toy cars)

Pulse-width controlled DC-motor power controller with a 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.

Neumann U47 tube microphone refurbish

This project gives you instructions and hints about constructing a fully working U47 tube microphone from old and/or refurbished parts. The instructions might be helpful also during the repair and restoration of these microphones.

Power supply for U-47 tube microphones

A highly capable special-purpose power supply for up to 6 Neumann U47 microphones. The power supply is fully regulated, foldback current limited, and can withstand indefinite constant short circuits. Output noise and ripple are very low (<200uVpp), a requirement for hum-less operation. Performance is better compared to the original power supply.

Animated Fortune Wheel

An 8-sector electronic fortune wheel simulator with effect lights and sound. Great for pre-school children and bazaars.

Home Intercom Using Existing Wired Telephones and House Wiring

This clever circuit adds to your old household wired POTS (Plain Old Telephone System) phones an intercom system - without disturbing the normal telephone operation. This design uses only 30 components, including the PSU!

Valentines' Day Animated LED-Heart

4-Band Parametric Audio Equalizer (tone control)

An 8-sector electronic fortune wheel simulator with effect lights and sound. Great for pre-school children and bazaars.

S-Video Chroma Processor

Realistic Traffic Light Simulator

An unorthodox and unique traffic light simulator using only op-amps or comparators! Simulates a car-lane and pedestrian light signals. Can run automatically or be controlled by a pedestrian push button. Controls small 5mm LEDs or optionally high power (low voltage) lamps.

60W Ultra-cheap & simple Audio Power Amplifier

The amplifier is very simple but gives a robust performance. The chosen components are a good compromise between performance and cost. The overall performance is very good. All used components are simple garden variety types, that can be found from many manufacturers and probably in your own junkyard. The amp is designed for 8-ohm loads, in which it can feed 40W continuous power with a distortion level of 0.1% or less. Instructions are unfortunately in Finnish.

40W TMOS Audio Power Amplifier

This is a schematic of a fully functional and well-behaving power MOSFET amplifier. It is compact, cheap and efficient and good-sounding. It also utilizes a unique "dual-bootstrap" technique, invented by the author. This simple idea guarantees that the output stage saturates symmetrically at both power supply rails, utilizing all available power supply voltage to always provide the highest possible peak power.

Simple DICE circuits

Throw you dices electronically.

Ultralow Frequency LED-beacon

An 8-sector electronic fortune wheel simulator with effect lights and sound. Great for pre-school children and bazaars.

4-channel Effects Dimmer

Throw you dices electronically.

One Minute Timer

Under Construction

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