LTKA Labs

Arduino BasicsEueung Mulyana

http://eueung.github.io/ET3010/arduinoET-3010 | Attribution-ShareAlike CC BY-SA

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https://github.com/eueunghttp://eueung.github.io/ET3010/arduinohttps://creativecommons.org/licenses/by-sa/4.0/

Outline

Short Intro

Quick Start

Networking

MQTT

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Short Intro

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ArduinoAn open-source hardware and software platform for building

electronics projects.

Arduino is an open-source electronics platform based oneasy-to-use hardware and software. It's intended foranyone making interactive projects.

Arduino senses the environment by receiving inputs frommany sensors, and affects its surroundings by controllinglights, motors, and other actuators.

You can tell your Arduino what to do by writing code inthe Arduino programming language and using theArduino development environment.

Several Arduino-Board variants exist e.g.: UNO, NANO,MEGA, DUE, YUN, etc.

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Quick Start

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This ChecklistPlease:

UNO BoardCompatible +Acessories

Components +Wires

ARDUINO IDE

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Tools - Config12 / 44

Sketch Upload13 / 44

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Project #1

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5V A0

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GND

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3V3

A1

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VIN

GND

GND

DIGITAL(PWM= )

Arduino TM

IOREF

ICSP

ICSP2

ON

POWER

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Fritzing Breadboard

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Project #1

D0/RX

D1/TXD2

D3PW

MD4

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D6PW

MD7

D8

D9PW

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D10PW

M/SS

D11PW

M/M

OSI

D12/M

ISO

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RESET2

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ioref

A0

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A5/SCL

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GND

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VIN

ArduinoUno

(Rev3)

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Red(633nm)

R1100

R210k

S1R310k

Fritzing Schematic

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Project #1 Sketchint inPin = 2; int outPin = 3; int potPin = A0;

int state = LOW; int reading; int previous = LOW;

long time = 0; long debounce = 1000;

int potVal = 0; int prevPotVal = 0;

void setup() { Serial.begin(9600); delay(500);

pinMode(inPin, INPUT); pinMode(outPin, OUTPUT); Serial.println("Program started ...");}

void loop() { reading = digitalRead(inPin);

if (reading && (millis() - time > debounce)) { if (previous == LOW) { Serial.println("[PHYSICAL] LED turned on"); state = HIGH; } else { Serial.println("[PHYSICAL] LED turned off"); state = LOW; }

time = millis(); digitalWrite(outPin, state); previous = state; prevPotVal = potVal - 10; } potVal = analogRead(potPin); if((state == HIGH) && (abs(potVal-prevPotVal)>4)){ analogWrite(outPin, potVal/4); Serial.print("[PHYSICAL] LED intensity "); Serial.println(potVal/4); prevPotVal = potVal; }}

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Serial Monitor20 / 44

Networking

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UNO + Ethernet Shield

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postingInterval) { httpRequest(); }}

void httpRequest() { client.stop();

if (client.connect(server, 80)) { Serial.println("connecting...");

client.println("GET /latest.txt HTTP/1.1"); client.println("Host: www.arduino.cc"); client.println("User-Agent: arduino-ethernet"); client.println("Connection: close"); client.println();

lastConnectionTime = millis(); } else { Serial.println("connection failed"); }}

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MQTT

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IoT ProtocolsThe IoT needs standard protocols. Two of the most promisingfor small devices are MQTT and CoAP.

MQTT gives flexibility in communication patterns and acts purelyas a pipe for binary data.

CoAP is designed for interoperability with the web.

Both MQTT & CoAP:

Are open standardsAre better suited to constrained environments than HTTPProvide mechanisms for asynchronous communicationRun on IPHave a range of implementations

See: MQTT and CoAP, IoT Protocols

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https://eclipse.org/community/eclipse_newsletter/2014/february/article2.php

ArchitectureCoAP packets are much smaller than HTTP TCP flows. Bitfieldsand mappings from strings to integers are used extensively tosave space. Packets are simple to generate and can be parsed inplace without consuming extra RAM in constrained devices.

CoAP runs over UDP, not TCP. Clients and servers communicatethrough connectionless datagrams. Retries and reordering areimplemented in the application stack. Removing the need forTCP may allow full IP networking in small microcontrollers. CoAPallows UDP broadcast and multicast to be used for addressing.

CoAP follows a client/server model. Clients make requests toservers, servers send back responses. Clients may GET, PUT,POST and DELETE resources.

CoAP is designed to interoperate with HTTP and the RESTful webat large through simple proxies.

Because CoAP is datagram based, it may be used on top of SMSand other packet based communications protocols.

CoAPCoAP is the Constrained Application Protocol from the CoRE(Constrained Resource Environments) IETF group.

ArchitectureLike HTTP, CoAP is a document transfer protocol. Unlike HTTP,CoAP is designed for the needs of constrained devices.

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MQTTMQTT is a publish/subscribe messaging protocol designed forlightweight M2M communications. It was originally developedby IBM and is now an open standard. It was designed in 1999for use on satellites and as such is very light-weight with lowbandwidth requirements making it ideal for M2M or IoTapplications.

ArchitectureMQTT has a client/server model, where every sensor is a clientand connects to a server, known as a broker, over TCP.

MQTT is message oriented. Every message is a discrete chunk ofdata, opaque to the broker.

Every message is published to an address, known as a topic.Clients may subscribe to multiple topics. Every client subscribedto a topic receives every message published to the topic.

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MQTTFor example, imagine a simplenetwork with three clients and acentral broker.

All three clients open TCPconnections with the broker. ClientsB and C subscribe to the topictemperature .

At a later time, Client A publishes avalue of 22.5 for topic temperature .The broker forwards the message toall subscribed clients.

The publisher subscriber modelallows MQTT clients tocommunicate one-to-one, one-to-many and many-to-one.

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MQTT - Publish / Subscribe

The publish / subscribe (often called pub-sub) pattern lies at the heart of MQTT. It's basedaround a message broker, with other nodes arranged around the broker in a star topology.This is a very different model to the standard client/server approach, and at first it mightseem a little strange, but the decoupling it provides is a huge advantage in many situations.

Clients can publish or subscribe toparticular topics which aresomewhat like message subjects.They are used by the broker todecide who will receive a message.

Topics in MQTT have a particularsyntax. They are arranged in ahierarchy using the slash character(/) as a separator, much like thepath in a URL. So a temperaturesensor in your kitchen mightpublish to a topic likesensors/temperature/home/kitchen.

See: Zoetrope

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https://zoetrope.io/tech-blog/brief-practical-introduction-mqtt-protocol-and-its-application-iot

That's all for now..

Enough talkingLet's get our hands dirty!!

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Project #2

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Arduino TM

IOREF

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ICSP2

ON

POWER

01TX

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RX0RESET

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SDCS

3 2 01TX RXAR

EF GND

5V A0

ANALOGIN

TX

RX

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3V3

A1

A2

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A4

A5

VIN

GND

GND

DIGITAL(PWMSPI)

SCL SDA