- Introduction
This project is about a hardware module for creating light effects using the red-, green- and blue-components of light emitting diodes (LEDs). This hardware module is based on an Atmel ATmega16 microcontroller and provides the possibility for managing 4 independent RGB-modules. A module is a collection of one red-, one green- and one blue channel. Each module uses a common anode and an output voltage of 12V DC. Therefore the common anode is connected to 12V DC and each color channel has to be switched against GND for light emission at the particular channel (we assume having the right dimensioned series resistors for current limitation integrated in the led module). At ATmega16 level we use pulse-width-modulation for each module's channels to mix an emitted color light.
- Features of the RGBLightControl PCB
• Atmel ATmega16 microcontroller with 16kB flash and bootloader support • USB interface (FT232RL) for managing the colors using a PC • parallel control of 4 independent RGB-LED modules (e.g. IKEA DIODER) • color control using RGB- or HSI triples! • 7-bit software PWM for seperate light intensity controlling of each channel! • support for 36kHz-RC5 IR remote controls • support for 3 pushbuttons • integrated RGB-LED for status display • pushbuttons are connected with ADC ports of the ATmega16 -> measuring of analog quantities possible (e.g. temperatures) • Input voltage: 12V DC • firmware completely written in AVR Assembler, therefore we have the features of: high speed, less memory, low crystal frequencies and low power consumance • AVRISP connector (soon bootloader support via USB)
- Requirements
3.1 PCB:
Schematic and board layout are completely designed using the freeware layout editor Eagle (Cadsoft) which is available for MS Windows and GNU/Linux at http://www.cadsoft.de.
3.2 Firmware:
To change and modify the firmware you may use any Atmel AVR Assembler you want. For convenience purposes I used Atmel's AVRStudio 4, available at http://www.atmel.com, but you are free to use any compatible assembler.
3.3 Software
The software is completely written in C++ as a makefile project and uses the GNU utilites for building an executable. The additional packages you should have installed for successful compilation and linking are some libraries of the Boost project (http://www.boost.org), in especially Boost ASIO, Boost Spirit, Boost Filesystem and Boost Thread. In Debian Linux you should therefore install the packages 'libboost-system-dev' and 'libboost-thread-dev' and 'libboost-filesystem-dev'.
For being able to communicate with the RGBLightControl pcb via USB, be sure to enable the modules 'usbserial' and 'ftdi_sio' in your linux kernel configuration. You should also ensure having the privileges for accessing the /dev/ttyUSB* devices as a simple user (Debian: dialout group).
The RGBLightControl software package also provides an integrated webserver for remote controlling the complete behaviour using standard web technologies. For this purpose, the boost::asio-based HTTP server "webEm" is used, a component written J. Bremner and C. Kohlhoff for proving include and action code parsing. The original "webEm" is licensed under BSD and available at Codeproject: http://www.codeproject.com/KB/IP/webem.aspx
3.4 Web-Frontend
Using HTML5, JavaScript and CSS it should be possible to provide a web application for easy starting or programming your favorite mood light using the internet browser of your smartphone/tablet! At the moment the HTML5 interface is still at a demo-stage using jscolor and prototype.js for AJAX requests.
- License
All files in this project are licensed under the GNU General Public License v3 or later. For more information about this license you should consult the Free Software Foundation at http://www.fsf.org.
- Contact
If you have questions, ideas, code, proposals or whatever, feel free to contact the author via mail.
Falk Schilling falk.schilling@gmx.net