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Diffstat (limited to 'what-is-iot.md')
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diff --git a/what-is-iot.md b/what-is-iot.md index c4a1a63..3b1b570 100644 --- a/what-is-iot.md +++ b/what-is-iot.md @@ -6,11 +6,11 @@ header-includes: allbordercolors={0 0 0}, pdfborderstyle={/S/U/W 1}} - \usepackage{tikz} - \usetikzlibrary{arrows,decorations.pathmorphing,backgrounds,fit,positioning,shapes.symbols,chains,shapes.geometric,shapes.arrows,calc} + \usetikzlibrary{angles,arrows,backgrounds,calc,chains,decorations,decorations.pathmorphing,decorations.pathreplacing,decorations.text,fit,positioning, quotes,shapes.arrows,shapes.geometric,shapes.symbols} !ifndef(QUICK) ~~~~~~ - \usepackage{fontspec} - \setsansfont{Verdana} + \setsansfont{Verdana} ~~~~~~ --- @@ -103,15 +103,15 @@ The ESP8266's RAM depends on which firmware stack is used. Physical is probably +--------------------------+----------------+ | State | Current usage | +==========================+===============:+ -| Off | 0.5 µA | +| Off | 0.5 µA | +--------------------------+----------------+ -| Deep sleep with RTC | 20 µA | +| Deep sleep with RTC | 20 µA | +--------------------------+----------------+ | Light sleep (with Wi-Fi) | 1 mA | +--------------------------+----------------+ | Sleep with peripherials | 15 mA | +--------------------------+----------------+ -| TX | 170 mA | +| TX | 170 mA | +--------------------------+----------------+ ::: notes @@ -241,6 +241,10 @@ Note that the "total length" field is 16 bits, 2 bytes, it's maximum value is 64 # Lecture: ESP8266 aka NodeMCU aka ESP-12 +## ESP8266 software layers + +!ifndef(QUICK)(!include(images/esp+arduino-sdks.pgf)) + # Lecture: MQTT ## MQTT @@ -248,23 +252,154 @@ Note that the "total length" field is 16 bits, 2 bytes, it's maximum value is 64 * *Message Queuing Telemetry Transport* * [Wikipedia: MQTT](https://en.wikipedia.org/wiki/MQTT) -## MQTT Implementations +::: 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). + +::: + +## MQTT - The protocol + +Agents have one of two roles: + +* *Client* + * Publishes *messages* + * Subscribes / unsubscribes to *topics* + +* *Broker* (aka Server) + * Handles network connections + * Keeps subscription state + * Manages client + * Disconnects + * *(last) will* + * Persistence + +::: notes + +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. + +::: + +## MQTT - The protocol - MQTT Topic + +* Topic name: `foo/bar/baz` +* Topic filter + * `foo/bar/?` + * `foo/#` + +## MQTT - The protocol - 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/$device-id/command` + +::: notes + +Typical first round of implementation. + +Commands can be: +* load new firmware (maybe an URL and firmware signature). +* Set new calibration values +* Change reading interval, altert levels (autonomous operation) + +::: + +## MQTT - The protocol - MQTT Packet + +* Size oriented +* Flags indicate type of remaining bytes + * Packet type + * Topic name + * Payload + +::: notes + +Only packet type + flags (1 byte) is required, everything else is optional. + +The size field is variable length encoded, 0-127 bytes is 1 byte, 128-16383 use 2 bytes etc, up to 4 bytes for 256MB payload. + +::: + +## MQTT - The protocol - MQTT Topic - more + +Enten må den holdes rett etter "## MQTT - The protocol - MQTT Topic" ellers kanskje flyttes etter "patterns". + +The central application is split: + +* An aggregating agent: + * `myapp/#/temperature` + * `myapp/#/humidity` +* Emailing agent + * `myapp/$device-id/altert` + +* Publishes on: + * `myapp/$device-id/command` + +::: notes + +::: + +## MQTT - Patterns + +Må utvides + +Explain: + +* Message sizes with MQTT +* "will" messages +* Push vs pull, central applications can push to clients +* mostly mqtt, some http + +## MQTT - Implementations * Mosquitto * Eclipse Paho -* Redis with MQTT connector +* 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 + * Amazon IoT + * Google Cloud IoT + * Microsoft Azure IoT + * CloudMQTT * DIY - * ThingMQ - * HiveMQ + * ThingMQ + * HiveMQ ::: notes @@ -275,11 +410,20 @@ In between are: ::: + # Notes -## Assignments +# Assignments + +## Assignment 1: Blink a led + +## Assignment 2: Connect to Wi-Fi + +## Assignment 3: Connect to MQTT broker + +## Assignment 4: Network play time * Measure round trip time/latency. Measure UDP, TCP. Measure when the packet size is greater than the MTU -* Measure ISR timing +* Notice variations in RTT |