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playground - MatrixMath
MatrixMath library for Arduino by Charlie Matlack contact: eecharlie in Arduino forums This library was modified from code posted by RobH45345, notably including replacement of the inversion algorithm. Briefly, the functions provided by MatrixMath : void MatrixPrint(float* A, int m, int n, String label); void MatrixCopy(float* A, int n, int m, float* B); void MatrixMult(float* A, float* B, int m, int p, int n, float* C); void MatrixAdd(float* A, float* B, int m, int n, float* C); void MatrixSubtract(float* A, float* B, int m, int n, float* C); void MatrixTranspose(float* A, int m, int n, float* C); int MatrixInvert(float* A, int n); Matrices should be stored in row-major arrays, which is fairly standard. The user must keep track of array dimensions and send them to the functions; mistakes on dimensions will not be caught by the library. It's worth pointing out that the MatrixInvert () function uses Gauss-Jordan elimination with partial pivoting.avr-libc: <math.h>: Mathematics
In order to access the functions declared herein, it is usually also required to additionally link against the library libm.a . See also the related FAQ entry . Math functions do not raise exceptions and do not change the errno variable. Therefore the majority of them are declared with const attribute, for better optimization by GCC.
ShiftOut
At sometime or another you may run out of pins on your Arduino board and need to extend it with shift registers. This example is based on the 74HC595. The datasheet refers to the 74HC595 as an "8-bit serial-in, serial or parallel-out shift register with output latches; 3-state." In other words, you can use it to control 8 outputs at a time while only taking up a few pins on your microcontroller. You can link multiple registers together to extend your output even more. (Users may also wish to search for other driver chips with "595" or "596" in their part numbers, there are many.
Arduino Interrupts | uC Hobby
Often when working on microcontroller projects you need a background function to run at regular intervals. This is often done by setting up a hardware timer to generate an interrupt. The interrupt triggers an Interrupt Service Routine (ISR) to handle the periodic interrupt. In this article I describe setting up the 8-Bit Timer2 to generate interrupts on an Arduino ATMega168. I walk through steps required for setup and inside the ISR function.Modkit
Modkit is an in-browser graphical programming environment for microcontrollers. Modkit allows you to program Arduino and Compatible hardware using simple graphical blocks and/or traditional text code. Modkit's graphical blocks are heavily inspired by the Scratch programming environment developed by the Lifelong Kindergarten Group at the MIT Media Lab. Modkit runs in your web browser and requires our Desktop Widget to communicate with your development board.