ARDUINO

Open Source

Open Hardware

A simple computer which can gather input from reality and interface outputs with the

environment however you instruct it to

http://arduinothedocumentary.org/

Fundamentals Of Arduino

• Write sketches or modify existing ones to suit your needs

• Wire an electrics circuit• Upload the sketches to the Arduino (via

USB connection) and connect the electrics circuit to the arduino, by joining wires to the sockets on the Arduino board

• 5V & GND : sources of power• Inputs and Outputs• Data transmission

Nomenclature

• On board sockets = Pins• Any numbered pin = input

or output• TX = transmitting

RX = receiving• Arduino AKA microcontroller

What is Arduino?

fig (i)

Sources of Power

The arduino has three GND pins and one 5V out The pins can be used to create a 5v DC circuit, _sufficient to illuminate an LED (fig ii, above) A resistor is necessary to ensure the current does not _burn out the LED

fig (ii)

Breadboard: An Arduinos Companion

The breadboard holds components external to Arduino Each socket on a breadboard connects to a conductive _horizontal or vertical strip

Electrical Circuits

The yellow trail indicates the positive pole of this circuit The green trail indicates the common or negative pole When both trails are linked by the LED, the circuit is _completed

fig (iii)

The Logic of Switches

The LED does not complete the circuit this time – _instead a button links the positive and negative poles _of the circuit A button can be pressed (ON) or not pressed (OFF) Depending on the buttons state (ON/OFF) the circuit is _complete or open

fig (iv)

Digital Pin :: input & output Digital means two possible

states HIGH/LOW = ON/OFF

5v – 0v = ON/OFF Programmed code tells the

arduino whether each pin is HIGH/LOW (aka on/off)

(The arduino assumes a pin to be off until told otherwise)

Input & Output: Digital

fig (v)

Digital Switches

This circuit is the same as fig (ii) This time the HIGH signal from digital pin 13 _supplies the 5v positive pole to the circuit

fig (vi)

Digital pins detect whether a circuit is in an ON or OFF state

When arduino measures voltage in a circuit it will register0 – 2.5v equal to LOW2.5v – 5v equal to HIGH

LOW == OFFHIGH == ON

Digital Sensors

fig (vii)

* Not just HIGH/LOW* Instead 0 – 5v is a wider

spectrum of values to measure

0 – 5v = 0 – 1023 in Arduino

Input & Output: Analog

* Analog Pin(s) :: input only* Analog is different to digital

*Analog equals continuous*Digital equals discreet

fig (viii)

Multimeter: Good Electronics Practice

• Multimeter reads resistance, voltage and ampage

• Multimeter is a big help to making sure you’re electronic circuit works the way it should:

• a circuit should always work the way you expect it before writing/amending arduino code

Other Variable Resistors

• LDR = Light Dependant Resistor

• Thermistor= heat dependant resistor

• GSR = Galvanic Skin Response

• FSR= Force sensitive resistor

Galvanic Skin Response

Thermistor

Serial Port Communication

Serial Port is how the Arduino Communicates with other Digital Devices (E.G. the computer or a digital SD card)

All computer tethered communications go via the serial port which arduino is connected to

Serial Port data can be accessed by software other than Arduino programming software (most readily via Processing)

Arduino can save data to SD cards using the TX and RX facilities (advanced feature)