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Galaxy Pattern Generator
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Avocamentum Galactica (http://douglasruuska.com/avocamentum-galactica/), the galaxy, a kinetic sculpture by Douglas Ruuska with electronics by Joshua Krueger, features at its core a PIC18F452 microcontroller running a pattern generator written in C. The pattern generator creates a serial broadcast that is received by the LED drivers to produce the color effects seen across the fiber optic stars of the galaxy's spiral arms. This project is that pattern generator. The star fibers are driven by 42 individually addressable RGB LEDs at 24 bits per pixel color resolution. There are 21 RGB LEDs per arm, aligned roughly sequentially. The software project consists of two build targets. The primary target is the galaxy's PIC and uses the serial port and galaxy hardware as the display output. This code was written using the C90 standard (with extensions) for the MicroChip XC8 compiler (v1.33). The secondary target was written to allow the code to be run on a general purpose computer with an emulated output shown in a graphical window. The build instructions in this file apply to the emulator target. To make this project in a build directory separate from the source: 1) Extract the archive somewhere convenient (like your home directory or Desktop): tar -zxvf galaxyEmulator-0.4.0.20141104.tgz Or, using git (preferred method): git clone https://github.com/argyle77/galaxyMaster.git EmulatorTarget 2) Enter the extracted directory and make a build directory. cd EmulatorTarget mkdir build cd build 3) Run cmake to generate the build scripts. cmake .. 4) Run make to compile and link the project. make 5) Once build is successful, run galaxyEmulator in the build/bin directory: bin/galaxyEmulator Hints: You may need to install the following packages: build-essential, cmake, libsdl2-gfx-dev, git To do this in an Ubuntu derivative environment, run the following command: sudo aptitude install build-essential cmake libsdl2-gfx-dev git When looking at this code, keep in mind that there are two build targets. Emulator code is demarcated in the source files using the c pre-processor define, "EMULATOR" (source enclosed in #ifdef EMULATOR / #endif), which the cmake build process automatically activates. It is sort of like having two overlapping programs that share a lot of common code. The emulator outputs the patterns to a window so that you can see a preview without needing the galaxy hardware on hand. I've broken the code into several files. Here is a manifest: README.txt - This file. The project build instructions and the file manifest. LICENSE.txt - Copyright notice and license for the project source and documentation. CMakeLists.txt - These files contain the cmake build instructions. Don't worry about them unless you want to change the version numbers. version.h.in - Totally unimportant. Used for versioning. deviceConfig.h - Lots of defines for setting up the PIC hardware. Not important for writing pattern code. galaxyConfig.h - Definitions specific to the galaxy. Some convenient constants and typdefs in here. init.h, init.c - PIC hardware initialization functions. Unimportant. display.h, display.c - Functions to write the pattern out to the LEDs. You won't need to change any of this. master.c - Contains main(). Calls the pattern generators. You probably won't need to change any of this. patternSupport.h, patternSupport.c - Contains helper functions that are useful in generating patterns. Currently available are: FadeChannel - Increases or decreases the intensity of all the LEDs of a given color channel. Shift - Rotates the color of all the LEDs up or down the arms by one step ColorAll - Set the color of all the pixels on the galaxy to a chosen color. GetRandomColor - Returns a random color in accordance with a selected mode. Examples of how these functions are used can be found in pattern.c pattern.h, pattern.c - A collection of pattern generation functions. This is where you put your pattern code. There are 6 examples already in this file. Add new patterns to patternList in pattern.h to get them to run. Pattern functions manipulate the galaxy->pixels array one step at a time. The loop in master.c calls your function over and over again and sends the results to the serial port (or to the emulator window) each time. The iterations field in the patternList tells the program how many times to call a particular pattern function before moving on to the next one. Patterns have access to the "initial" variable, which is set to TRUE the first time a new pattern function is called, and FALSE every time thereafter. Pattern functions can use static variables to keep track of state information between calls. Code pieces that you write that might be useful for multiple patterns may be candidates for inclusion as functions in patternSupport.c. The emulator timing is not exact and may be thought of as suggestive of what a pattern might look like on the galaxy itself. When run, the emulator will print out a list of available key-presses to the terminal window so that you'll know how to use it. The code, as it stands, occupies 22% of the PIC data memory (RAM) and 30% of the PIC program space (flash). The PIC can use floating point variables and functions, but these are very memory and CPU intensive and may not result in the timing you desire. The PIC only has 1536 bytes of RAM, so keep in mind that though the emulator target can compile and run anything (I personally have giga- bytes of RAM available to it), the galaxy itself is somewhat more limited. I built this project using the Linux Mint operating system, which is an Ubuntu derivative. It should be very easy to get it running on any Ubuntu derivative, and relatively easy to get it running on other popular linux distributions. With the right software and libraries installed, you may even be able to build it in Windows or MAC (thanks to cmake), but I have little experience programming for either of these platforms. To build the code for the PIC target rather than the emulator target, I suggest obtaining a copy of MPLAB X IDE: http://www.microchip.com/pagehandler/en-us/family/mplabx/ as well as the XC8 compiler: http://www.microchip.com/pagehandler/en-us/devtools/mplabxc/home.html both of which are available for multiple operating systems at no charge from MicroChip. Create a simple Microchip Embedded, standalone project with the PIC18F452 and the XC8 compiler selected and add the source files to your project. There should be no special settings or flags required for compilation in this environment. If you use a different PIC for this project, you'll find most of the stuff you need to change in deviceConfig.h This project's use of git and presence on github are the author's efforts to learn to use these tools.