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diff --git a/slides/connected-arduino.md b/slides/connected-arduino.md new file mode 100644 index 0000000..6a6b5e7 --- /dev/null +++ b/slides/connected-arduino.md @@ -0,0 +1,565 @@ +--- +title: "IoT Workshop" +author: Trygve Laugstøl \<trygvis@trygvis.io\> +header-includes: + - \hypersetup{colorlinks=true, + allbordercolors={0 0 0}, + pdfborderstyle={/S/U/W 1}} + - \usepackage{tikz} + \usetikzlibrary{angles,arrows,arrows.meta,backgrounds,calc,chains,decorations,decorations.pathmorphing,decorations.pathreplacing,decorations.text,fit,matrix,positioning,quotes,shapes.arrows,shapes.geometric,shapes.symbols} + +!ifndef(QUICK) +~~~~~~ + - \usepackage{fontspec} + \setsansfont{Verdana} +~~~~~~ + +--- + +# NodeMCU + +!comment(aka NodeMCU aka ESP-12) + +## NodeMCU hardware + +!ifndef(QUICK)( + +) + +## NodeMCU hardware + +!ifndef(QUICK)( +\begin{center} +!include(images/nodemcu.pgf) +\end{center} +) + +## ESP8266 software layers + +!ifndef(QUICK)( +\begin{center} +!include(images/esp+arduino-sdks.pgf) +\end{center} +) + +## ESP8266 + Arduino + +* Standard Arduino IDE +* ESP8266 Arduino core + * https://github.com/esp8266/Arduino + +## Arduino IDE + +!ifndef(QUICK)( + +) + +## Arduino code structure + +~~~ .c++ +void setup() { + // Called once +} + +void loop() { + // Called repeatedly +} +~~~ + +::: notes + +MCU programming is often structured into: + +* Configure + * CPU + * GPIO ports + * MCU's peripherals + * The rest of the board + * Configure application and callbacks. +* Sleep + +Arduino chooses to run the cpu at 100% instead of the sleep step.. + +::: + +## Arduino file structure + + foo/ + foo.ino + config.h + +::: notes + +`foo.ino` must always be in a `foo` directory. + +config.h is created by "new tab". + +::: + +## Generic Arduino APIs + +~~~c++ +// Pin: D0, D1, etc. +// Mode: OUTPUT, INPUT, INPUT_PULLUP +void pinMode(uint8_t pin, uint8_t mode); + +// State: HIGH, LOW, true/false, 1/0 +void digitalWrite(uint8_t pin, uint8_t state); +int digitalRead(uint8_t pin); + +unsigned long now millis(); +unsigned long now micros(); +~~~ + +## ESP Arduino APIs + +~~~c++ +class { + void restart(); + uint32_t getFreeHeap(); + uint32_t getChipId(); + + ... +} ESP; + +// Usage +ESP.restart(); +~~~ + +## ESP Arduino APIs + +~~~c++ +class { + String macAddress(); + + wl_status_t status(); + int32_t RSSI(); + + IPAddress localIP(); + IPAddress subnetMask(); + IPAddress gatewayIP(); + IPAddress dnsIP(uint8_t dns_no = 0); + + ... +} WiFi; + +// Usage: + +Serial.println(WiFi.localIP().toString()); +~~~ + +::: notes + +http://arduino-esp8266.readthedocs.io/en/latest/libraries.html + +::: + +# What is IoT + +## What is IoT + +* Not "a computer connected to the internet" + * Then it is really just another computer connected to the internet + +* Must be something else + * It is simply devices that are resource constrained + * Usually in more than one way + +* Autonomous operation, the connection might not be permanent + +## IoT is just a concept + +* *The Internet of Things (IoT) is the network of physical devices, + vehicles, home appliances and other items embedded with + electronics, software, sensors, actuators, and connectivity which + enables these objects to connect and exchange data.*^[ + Wikipedia "Internet of Things"] + +## What is an IoT Device? + +::: notes + +As for their definition. + +What differentiates a computer from an IoT device? + +::: + +## What is an IoT Device? + +* Constrained in (one or more of): + * Memory + * CPU + * Network bandwidth and/or latency + * Storage +* Has connectivity + * Bluetooth + * Wi-Fi + * NB-IoT + * LTE Cat-M + * LoRa + * Proprietary radio + +::: notes + +Might not have: + +* RTC + +Extra features: + +* IR +* UART +* CAN + +Sparkfun and Adafruit etc sell modules with all of these technologies. + +::: + +## IoT Devices - Example chips + +Protocol Chip Specs +------------- ---- ----- +Bluetooth 4/5 nRF52x 32-64 MHz, Cortex-M0/M4F, + 24-256k RAM, 192-1024 k Flash, + $1.88-$3.85 +WiFi ESP8266/ESP32 80MHz-160MHz, 1-2 cores, + ~80k RAM, < $1 - $4.53 +LoRa Semtech $3.23 - $4.74 + + +::: notes + +BT and Wi-Fi has many, many more chips. Technologies based on +open/accessible standards. LoRa is much more closed and driven by a +single company. + +4.53 is quantity=10 + +LoRa chips are just trancievers, an MCU with LoRa stack is required. +::: + +## ESP8266 details - Power usage + ++--------------------------+----------------+ +| State | Current usage | ++==========================+===============:+ +| Off | 0.5 µA | ++--------------------------+----------------+ +| Deep sleep with RTC | 20 µA | ++--------------------------+----------------+ +| Light sleep (with Wi-Fi) | 1 mA | ++--------------------------+----------------+ +| Sleep with peripherials | 15 mA | ++--------------------------+----------------+ +| TX | 170 mA | ++--------------------------+----------------+ + +::: notes + +Datasheet page 18 + +::: + +# Lecture: MQTT + +## MQTT + +* *Message Queuing Telemetry Transport* +* [Wikipedia: MQTT](https://en.wikipedia.org/wiki/MQTT) + +::: notes + +MQTT is *the* standard for IoT applications (and lots of other useful +stuff to). Using HTTP is just silly. + +Supports SSL, and requires TCP. + +Has UDP-like semantics with "fire and forget" but on a higher level +(the message always have to be delivered and ACKed by the broker, not +it's final recipient. + +Version 3.1.1 er den som gjelder, V 3.1 er rar, de andre finnes ikke +(før standardisering). + +::: + +## Device and application architecture with MQTT + +!ifndef(QUICK)( +\begin{center} +!include(images/mqtt-example-architecture.pgf) +\end{center} +) + +## MQTT - Implementations + +* Mosquitto +* Eclipse Paho +* RabbitMQ +* ActiveMQ + +::: notes + +RabbitMQ has a separate connector that must be installed +Not sure about ActiveMQ but it is at least a part of the project so it is releases at the same time. + +::: + +## MQTT Cloud Connectors + +* Cloud + * Amazon IoT + * Google Cloud IoT + * Microsoft Azure IoT + * CloudMQTT (at Heroku) + +* DIY + * ThingMQ + * HiveMQ + +::: notes + +In between are: + +* self hosted +* Generic bridges + +::: + +## MQTT - The protocol + +Agents have one of two roles: + +* *Client* + * Publishes *messages* + * Subscribes / unsubscribes to *topics* + +* *Broker* (aka Server) + * Handles network connections + * Keeps subscriptions + * Manages client + * Disconnects + * *(last) will* + * Persistence of retained messages + +::: notes + +network connections: this includes removing closed sockets, client's that doesn't respons to timeouts and duplicate clients. + +http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html + +Subscriptions are not permanent. The connection is (unlike HTTP) +stateful. + +Some messages may be persistent, but only one per topic. You will +often end up with a "proper" mq on the backend if queuing is needed. + +Push vs pull, central applications can push to clients + +::: + +## MQTT - The protocol - MQTT Packet + +* Size oriented +* Flags indicate type of remaining bytes + * Packet type + * Topic name + * Payload + +::: notes + +Only packet type + flags (1 byte) is required, everything else is optional. + +The size field is variable length encoded, 0-127 bytes is 1 byte, 128-16383 use 2 bytes etc, up to 4 bytes for 256MB payload. + +::: + +## MQTT Connect + +* `CONNECT` + * `clientId` + * `username` + * `password` + * `keepAlive` + +<!-- --> + +* Keep alive + * `PINGREQ` + * `PINGRESP` + +## MQTT - The protocol - MQTT Topic + +* Topic name: `foo/bar/baz` +* Topic filter + * `foo/bar/?` + * `foo/#` + +## MQTT - The protocol - Retained message + +Message is kept by the server even after disconnect + +* `CONNECT` +* `PUBLISH` + * `RETAIN` + * `$app/$device/temperature` + * `22.3` +* `DISCONNECT` + +Later on: + +* `SUBSCRIBE` + * `$app/#/temperature` +* `PUBLISH` + * `$app/$device/temperature` + * `22.3` + +::: notes + +The last PUBLISH is an incoming message + +::: + +## MQTT - The protocol - Will message + +Message sent when you disconnect + +Client #1: + +1. `CONNECT` + * `WILL TOPIC: $app/$device/online` + * `WILL PAYLOAD: 0` +1. `PUBLISH` + * `$app/$device/online` + * `1` +1. `DISCONNECT` + +Broker + +1. *To all subscribers* `PUBLISH` + * `$app/$device/online` + * `0` + +## MQTT Topic + +The temperature sensor: + +* Publishes on: + * `myapp/$device-id/temperature` + * `myapp/$device-id/humidity` + * `myapp/$device-id/altert` +* Subscribes to: + * `myapp/$device-id/command` + +The central application: + +* Subscribes to: + * `myapp/#/temperature` + * `myapp/#/humidity` +* Publishes on: + * `myapp/$device-id/command` + +::: notes + +Typical first round of implementation. + +Commands can be: +* load new firmware (maybe an URL and firmware signature). +* Set new calibration values +* Change reading interval, altert levels (autonomous operation) + +::: + +## MQTT on Arduino + +PubSubClient is our MQTT client implementation. + +~~~c++ +WiFiClient wifiClient; +PubSubClient mqtt(wifiClient); + +void callback(char* topic, + byte* payload, + unsigned int length); + +void setup() { + // Configure WiFi + mqtt.setServer(mqtt_server, 1883); + mqtt.setCallback(callback); +} +~~~ + +## MQTT on Arduino + +~~~c++ +void loop() { + if (!mqtt.connected()) + reconnect(); + else + mqtt.loop(); + // Do work +} + +void reconnect() { + while (!mqtt.connect(client_id)); + + mqtt.subscribe(topic_pattern); +} +~~~ + +::: notes +This is blocking! +::: + +## Assignment + +* `mqtt` + +## MQTT topic architecture + +The central application is split: + +* An aggregating agent: + * `myapp/#/temperature` + * `myapp/#/humidity` +* Emailing agent + * `myapp/$device-id/altert` + +* Publishes on: + * `myapp/$device-id/command` + +## MQTT topic architecture + +!ifndef(QUICK)( +\begin{center} +!include(images/mqtt-example-architecture.pgf) +\end{center} +) + +## MQTT topic architecture + +!ifndef(QUICK)( +\begin{center} +!include(images/mqtt-example-architecture2.pgf) +\end{center} +) + +## MQTT - Patterns + +* Combining MQTT and HTTP +* Using web sockets transport + +## Assignment + +* `mqtt2` + +## Assignment + +* `mqtt3` + +::: notes + +discussion: how to connect these two devices? + +::: |