Snippets and Sketches.

AVR Related

• PinChangeIntExample - an example sketch using the PinChangeInt library
• Adjusting Arduino PWM Frequencies
• ShowInfo - Show what the Arduino has to tell you

Ethernet Shield

• TFTP Bootloader alternative 1 bootloader to use the Arduino Ethernet Shield or the Arduino Ethernet Board with a bootloader that will allow upgrading the Firmware via TFTP.
• Web Client Web client code loads page every 30 seconds.
• Web Server Web server code with javascript alert and two form fields.
• FTP passive client FTP client code for ethernet shield
• Email client Email client code for ethernet shield
• Webduino file server: A file server sketch based on Webduino

WiFi

• Garg10n3 sketch to interface a low cost fonera access point with arduino to make a wifi camera-equipped rc car.
• WiFly HTTP temperature server A HTTP server that displays the current temperature, using a WiFly Shield and an LM35 CAZ. Also can send how much memory is free for diagnostics.

Clocks

• DCF77 Clock - a binary DCF77 clock with good noise tolerance.

Concurrency, Timing & Schedulers

• heartbeat sketch - use an array to create an irregular blink pattern
• Stopwatch Sketch: doing multiple things at the same time.
• A Delay Sketch: An easy to use "blink without delay" style sketch written to be used with the ease of "delay()".
• Multi Blink: Demonstrates a table driven approach to concurrency by blinking lots of LEDS at different speeds. The technique is extensible to many other situations.

Input / Output

• PWM Techniques
  • PWMallPins - a sketch to get more PWM pins
  • atmega_i2c_pwm_expander - sketch to use an ATmega as a PWM expander, controlled by I²C
  • 8-bit PCM audio (on a PC speaker)
  • Creating Variable frequencies for PWM @ anything from a 15Hz to 1MHz
  • Create PWMs in-sync and out of sync Create PWMs in-sync and out of sync
  • 8/9/10-bit compressed audio output @ 8k, 10k, 12.5k, 16k, 20k, 25k, 40k sample rate.
  • Using the TLC5940 to run PWM at different frequencies
  • Adjusting the TLC5940 libraries to give different PWM frequencies
  • Using TLC5940 to give phase-shifted PWM Signals

• Blinking
  • Blinkenlight Experiments Blinking 20 LEDs, POV, Knight Rider, flicker free PWM and more experiments.
  • PulsePattern Generate a repeating pulse pattern with Timer1
• Metrology
  • Supply Voltage Measurement - How to determine the (regulated) supply voltage of an Arduino.
  • A one led voltmeter: so as to say the voltmeter of the poor
  • LCD voltmeter: so as to say the voltmeter of the rich
  • Direct Math Voltmeter: understandable math for voltage dividers
  • Capacitance Meter sketch
  • Logic Analyzer: a very simple logic analyzer sketch. 1024 samples at 5.3 MHz
  • Thermal Imaging a rudimentary 20 pixel thermal imaging device.
  • An other capacitance meter explained and documented

• Touchscreen Piano: Arduino IDE ver. 1.0.1 sketch for using a 2.8" Touch Shield on an Arduino Uno or Mega to make a little "piano".

• Using multiple devices (including Arduinos!) on an I2C bus
• Getting multiple Serial channels with an Arduino
• ReadReceiver a sketch that uses Timer1 and PinChangeInt to read PPM output from a standard RC car Receiver

Storage

• EEPROM Load and Save - A sketch to Load and Save settings from/to the EEPROM
• EEPROM Wear Leveling An example for extending EEPROM endurance by wear leveling

Communication

• SMARTGPU Create full Color touchscreen advanced GUIs with serial communication.
• Streaming output: A DIY way to get <<-style output with Serial/LCD/Ethernet/etc.
• Input commands via serial interface and program outputs & operations: Code explains how to talk to Arduino using Serial input, and process the command and return results
• YahooNetworkTime: Code to access the network time from a Yahoo server and set the Arduino clock to match.
• Serial comm ports for ever, and ever, and ever…

General

• String Functions
  • FindText: A simple function to search for some text within a string.
  • tempToAscii - Convert a float to ascii string with 3 decimal places
  • printf() simple shell around vsnprintf() letting you use send printf style format strings over serial.
• Arduino Doodles - Mixed bag of sketches and libraries.

Math

• Prime number generation sketch
• smooth(data, filterVal, smoothedVal) - a low-pass filter smoothing function, useful for removing sensor jitter
  • digitalSmooth(data, smoothArrayName) - a digital low-pass filter smoothing function, useful for removing sensor jitter, and glitches
• autoscale(int originalMin, int originalMax, int newBegin, int newEnd, int inputValue) - scale a variable between two ranges using linear interpolation
• fscale(float originalMin, float originalMax, float newBegin, float

newEnd, float inputValue, float curve) - a function to map a variable between two floating point ranges. Can logarithmically favor either end of the output range.

• smoothstep - a function to ease from one value to the next with a smooth "s" shaped logarithmic curve.
  • nonlinear mapping - reMap() allows to adapt a nonlinear function with line segments.
  • multiMap - multiMap() allows to adapt functions with interpolation - similar as reMap() above - but this one is 100% integer to improve speed, and a bit more hardened.
• randomHat() - choose every number from a "hat" before repeating
• randomWalk(stepSize) - wander between endpoints at a specified rate
• freqout(freq, duration) - a simple frequency generator
• Musical Algo Fun - Sketech for making music with old PC speakers
• Armstrong Music System - a collection of input and output abstractions to ease the development of musical instruments with the Arduino. This abstraction also allows sounds trigger remote hardware (PC or synthesizer) without additional coding.
• Pulse Width Determination
• Measuring frequency with Arduino - A small and simple code snippet for 0 - 100 kHz range
• FFT tutorial: Learn how to implement Fast Fourier Transform in Arduino
• FIR filters tutorial: Learn how to implement FIR (Finite Impulse Response) filters in Arduino
• PID tutorial: learn how to use PID for temperature control