The aim of this project is the development of comfortable standalone digital lighting controllers (“dimmers”) for home use, which are inexpensive, easy to build, yet very feature-rich and highly configurable.
All development details, such as the microcontroller operating systems (firmware), schematics, board layouts, and documentation, are freely available under the GNU General Public License (GPL), version 2.
This project was founded on May 1, 2003.
Until today, two lighting controller models have evolved from this project:
- Semitone Crystal: The first controller developed for this project. A simple one-channel fading controller with IR remote input, UART, push-button connector, 3 LED indicators. 50 Hz/230V mains only.
- Semitone Diamond: The flagship of the Semitone project. An advanced, very feature-rich 20 channel fading controller with character LCD, IR remote input, DMX512 interface, buttons, rotary encoder, and more. Supports both 50 Hz/230V and 60 Hz/115V mains.
Apart from the official releases there are SVN development versions available. Especially for the Diamond model these versions have many feature enhancements as well as changed hardware requirements. Please check out the EngDR.
All Semitone dimmer models are controlled by Atmel AVR® RISC microcontrollers.
||300 W (resistive load only!)
||(depends on output stage)
TRIAC: 300 W (resistive load only!)
FET/IGBT: 300 W (resistive load only!)
|User interface (input)
||RC5 capable IR remote control
standby push button
|RC5/RC6 capable IR remote control
|User interface (output)
||20×2 character LCD
20×4 character LCD *
||USITT DMX512 (250 kb/s or 9600 kb/s)
SLCPv0 (dedicated; still to be defined)
* Feature currently only available in development version. Check out the Semitone Diamond Trunk.
One important design goal was to develop a system with minimum and inexpensive hardware that is easy to recreate.
The core of each lighting controller is a microcontroller which is programmed with this project's firmware. A microcontroller is a microprocessor with ROM, RAM and many other units integrated in a single chip.
The Atmel AVR® is a very powerful, popular, yet inexpensive microcontroller series with an 8 bit RISC core, using the Harvard architecture (program memory separated from data memory). You can find more information at the AVR® website. All microcontroller models in this project are available in DIL packages and thus easy to solder with standard equipment.
The Semitone Crystal uses the ATtiny2313 (or the obsolete model AT90S2313), programmed in assembler. This controller has 2 kB of flash memory, which is almost completely in use. So, unfortunately, there is no way of adding more features to this model.
The Semitone Diamond uses the ATmega644, programmed in C (using avr-gcc). This controller model has 64 kB of flash memory, which is enough for the current firmware version, and even for many more features.
Note: Support of the ATmega32 was dropped with version 2.0.0 of the Diamond RTOS.
Pre-programmed microcontrollers can be ordered from Engbedded (see products list). World-wide shipping is no problem.
The rest of each device is few analogue stuff and – depending on the model – some more ICs.
The price for the Semitone Diamond is around 20 € for the mainboard parts, plus the 20 x 2 HD44780 character display (which varies from 4 € to 40 €, greatly depending on the size, backlight configuration and color), plus the output driver stages (depending on the kind of output you want to drive with each channel – e.g., calculate 5 € per TRIAC channel), plus buttons, wheel and case (completely depends on your wishes and expectations).
The price for the parts of the Semitone Crystal is around 12 € for the mainboard, including LEDs and output driver stage.
You can obtain all packages released by this project from our SourceForge Download Page.
Supporting this project
This is a free non-profit project. If you like this project and want to donate, then I'd be more than happy to add your name to the list of our generous donors.
To donate money, please click one of the buttons at the right. Many thanks in the name of all users!