Electronics projects


Uppdaterad: 2012-02-12
Publicerad: 2008-11-06

Some electronics projects designed and built by Hans Sundgren.

DCF77 Simulator

DCF77 Simulator

Description: A combined simulator and demonstrator of the DCF77 system used for setting time of radio-controlled clocks. The time setting protocol is demonstrated by light, text and sound.

Challenges: The first PIC-project designed by Hans. Three different PIC-processors were used in the end. One rotary encoder is used for both setting volume and selecting sound type.

Ready: 2010

More information: DCF77 Simulator


ARDF sound transmitter

Description: An ARDF transmitter with voice identification. The timer transmits any recorded sound message at a set interval on 144 MHz. The designed is using the SquawkBox transmitter circuit from Doppler DF Instruments Bob Simmons.

Design challenges: Robust construction and small size. Adapted for connection to an existing VHF transceiver for higher power output.

Ready: 200X.

Antenna tuner

Antenna tuner

Description: The tuner was bought as a kit with components, but the design was changed. The tuner was put in a robust aluminum enclosure.

Design challenges: Robust construction and small size.

Ready: 2004.

Antenna tuner, inside Antenna tuner from the sidde 


Automatic decision maker

Description: A random yes/no generator.

Design challenges: Small size, adapted for mass production and a single pushbutton for on/off/start which means an auto power off function.

Ready: 1994.


Meeting cost counter, compact

Description: A small pocket size version of the meeting cost counter.

Design challenges:Putting it all together in a small box including thumb weel switches for setting the rate. By using an LCD display with integrated counter it was quite easy.

Ready: 1992.


Meeting cost counter

Description: A measurement tool for meetings. By multiplying the number of persons and average hourly rate you get a cost per hour. Enter this rate on the slider and press the start button. The display will then start to count the accumulated cost. This means that you can say to a person: "John, you can speak for 10 dollars now." Today there are software based Meeting Meeters™ but this one was made before the computers were common.

Design challenges:Everything on one board, no enclosure.

Ready: 1990.

Morse keyer

Touch controlled morse keyer

Description: Touch sensitive keyer without mechanical switches. Based on a combination of Curtis Keyer 8044 chip and a proximity switch circuit.

Design challenges: Compact unit with all circuits including batteries. Mechanical design of "paddles" that turned out to be two wall hooks for clothes.

Ready: 1990.

Morse keyer, rear Morse keyer, front

Morse keyer, inside


Thank-you-blinker with integrated music horn

Description: Originally a music horn for the car expanded with a thank-you-blinker.

Design challenges: Robust construction to be able to widthstand the vibration and high temperature in the engine compartment of the VW Golf. As few cables as possible to simplify the retro-fit in a new car. SCART-contact was used for the multi-conductor cable between the engine compartment and the dashboard with rocker switches and thumbwheel switches.

Ready: 1989. Removed from the car and scrapped 1999.

Music synthesizer

Music synthesizer

Description: Building a music synthesizer from a kit from USA. The circuit board was bought from USA but the mechanical design was developed by Hans. The project was documented as a part of a special project in the high school Berzeliusskolan in Linköping.

Challenges: The mechanical design using a separate main unit and a full size keyboard. Describe the design of the synthesizer.

Ready: 1976

Music synthesizer, inside

pdf Description, 11 pages, in Swedish

Handheld sounder

Description: An electric bell controlled by a push-button. The design was based on components bought from Clas Olsson and what was available in Hans' fathers hobby room.

Challenges: Small hand-held unit with all components integrated; electric bell, push-button and batteries.

Ready: 1964