Arduino
What is Arduino
- Open-source electronics prototyping platform
- Hardware
- arduino boards
- arduino Shields
- additional hardware
- sensors (input)
- actuators (output)
- Software
Hardware
- Arduino boards
- Prebuilt or build it yourself with help of open reference design
- Contains:
- micro-controller
- memory
- pins for interaction
- Arduino shields
- Additional board that can be mounted on arduino board to provide additional capability
- Official shields: ethernet, wireless (Xbee) and motor
- Additional hardware
- Inputs: buttons, keyboards,
- outputs: motors, leds, screens
Interaction
- Inputs to arduino
- Manual manipulation: Buttons, rotation sensors, bending,
- RFID, gps
- Environment: temperature, gas, camera, microphones, light sensors, noise sensors
- outputs from arduino
- to computer: usb, wireless connectivity (BT, wi-fi, xbee)
- to environment: leds, displays, motors, speakers,
Software
- Software is developed for the microcontroller
- mostly defines what output is
- Arduino programming language
- Simplified C/C++
- Based on wiring (http://wiring.org.co/) open-source programming framework for micro controllers
- Arduino program is called sketch
- programs are stored in sketch book at Arduino IDE
- Arduino IDE
- Simplicity based on ideas of Processing
- open source http://www.processing.org/
- Processing is java based while arduino is C based
- Designed to be easy for people not familiar with software developers
- Artists are one big group using arduino
- code editor
- compling and uploading programs to arduino board with one click
Developing software
- arduino → C → microcontroller
- Arduino is simplified C and only minor changes is done on compiling to C
- Remember Arduino has little memory
- try to use int instead of float
- avoid unnecessary #includes
Program structure
- void setup()
- setup() function is run only once when sketch starts
- void loop()
- loop() function runs continuosly after the initial setup
- When program goes at the end of loop function it goes back at the start of loop
- Arduino translation to C code and inserts arduino setup and loop inside C main()
- Arduino build creates functions inside C main function
- int main (void) { init();setup(); for(;;) loop; return 0;}
- init setups the hardware
- Developer needs to concentrate only on setup and loop
Special functions
- constrain (a, low , high)
- Limits the variable a values between low and high
- int temperature = constrain (temperature, 0, 24)
- map (a, low, high, newlow, newhigh)
- maps the value of variable a on scale low to high to scale newlow to newhigh)
- newlow and newhigh can be used for reverse mapping e.g. int debet = map (credit, 0, 10, 0, -10)
Controlling PINs
- Arduino board has digital and analog pins
- PINs can be defined as input or output PINs
- const int outPin = 11;
- const int inPin = 12;
- pinmode (outPin, OUTPUT);
- pinmode (inPin, INPUT);
- Input pins can be read, output Pins can be written on
- val = digitalRead(inPin);
- digitalWrite (outPin,HIGH);
- digital Pins returns either HIGH or LOW and can write either HIGH or Low
- analog Pins can have variety of values.
Xbee
- IEEE 802.15.4 standard based communications between arduino boards
- e.g. Zigbee
- Virtualwire library helps the creating communication over Xbee
- See details: http://www.open.com.au/mikem/arduino/
