Long time ago i saw this unusual door bell at the make:blog. I loved the idea instantly! Even though the project is quite simple, it took me one year (sic) to get it done.

I didnt like the concept of using a electromagnet for playing the sound. I preferred a servo motor controlled by a microcontroller (Atmega8) to do the job (side effect: programmable “melodies”).

• The setup is quite easy:

- The two glasses (Butlers) are srcewed to a wooden board (OBI)
- The servo (Conrad) is attached to the board via angle brackets (OBI) by tie wraps
- The wooden spoon (Ikea) is attached to the servo by tie wraps
- The board has two colored LEDs attached to the glasses fixated by hot-melt adhesive

The circuit board is a very simple layout (all parts Reichelt):
- Atmega8 (internal clock)
- ISP connector for programming
- Connector for servo
- Connector for 5V power supply
- Resistors for LED
- Button for testing
- The unused connector will carry the radio receiver in the future

Lessons learned:
- The glasses need a bit more spacing so the servo/wooden spoon has better momentum
- Include a RS232 connector in the layout for calibrating servo frequency/wait time

• Downloads