Electronics projects

Some electronics projects designed and built by Hans Sundgren

The DCF77 Simulator, built 2010.

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, built 200x.

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, built 2004.

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.

Inside view and side view of the antenna tuner.
Decision maker, built 1994.

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.

Compact meeting cost counter, built 1992.

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 wheel switches for setting the rate. By using an LCD display with integrated counter it was quite easy to design the unit.

Ready: 1992.

Meeting cost counter, built 1990.

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, built 1990.

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" using two wall hooks for clothes.

Ready: 1990.

Morse keyer rear and front view.
Morse keyer, inside view from the bottom.
Thank-you-blinker, built 1989.

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 withstand 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.

End-of-life: 1999. Removed from the car and scrapped.

Music synthesizer, built 1976.

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

End-of-life: 19xx. The synthesizer was sold to a private person.

Description, 11 pages, in Swedish

Music synthesizer, circuit boards and front panel.
Handheld sounder, built 1964.

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' father's hobby room.

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

Ready: 1964

End-of-life: 1968. The device is too simple to be kept and is scrapped.

Foto-information

Fotograf

Hans Sundgren, om inte annat anges.

Kamera

Canon Ixus 950IS