IoT & Embedded Systems

The small computers inside everyday things: microcontrollers, sensors and radios, how devices talk to each other and to the cloud, the Dutch smart meter as a worked example, and how to keep thousands of connected devices updated and secure.

16 pages 125 glossary terms

How to use this topic

This topic builds on Hardware, which covers the personal computer, and sits next to OT & Industrial Control Systems, which covers industrial control. The first seven pages are about the device itself: what IoT is, the boards, sensors and actuators, pins and buses, power and firmware. Pages 8 to 12 follow the data from the device to the cloud: radios, MQTT, the smart meter and its P1 port, gateways and platforms. The last four cover keeping devices updated and secure, handling their data, and IoT at home and in buildings.

Hardware such as pins, radios and logic analyzers could not be connected to the test machine, so that output is marked illustrative. The MQTT output was recorded with a real broker on the test machine, and the calculations, protocol decoders and checks are short programs with their exact output.

Learning path

  1. 01What Is IoT?What the Internet of Things is and how it relates to embedded systems and operational technology: devices, gateways, platforms and users, typical uses, and why IoT is hard to do well.Beginner
  2. 02Microcontrollers and Single-Board ComputersThe two kinds of brains in IoT devices: microcontrollers such as the ESP32, Arduino boards and the Raspberry Pi Pico, single-board computers such as the Raspberry Pi, and how to choose between them.Beginner
  3. 03Sensors and ActuatorsHow devices sense and act on the physical world: analog and digital sensors, analog-to-digital conversion, resolution, noise and calibration, and actuators such as relays, motors and LEDs.Beginner
  4. 04GPIO, PWM and InterruptsTalking to the outside world pin by pin: digital inputs and outputs, pull-up resistors and debouncing, pulse-width modulation, polling versus interrupts, and voltage levels that must not be mixed.Intermediate
  5. 05Bus Protocols: UART, I2C and SPIHow chips on one board talk to each other: serial UART, the two-wire I2C bus with addresses, the fast SPI bus, when to use which, and how to debug them with a logic analyzer.Intermediate
  6. 06Power and BatteriesKeeping a device alive on little energy: supply voltages and regulators, battery capacity, sleep modes and duty cycles, calculating an energy budget, and harvesting energy.Intermediate
  7. 07Firmware and Embedded ProgrammingWriting the software that runs on the device: C and C++ with frameworks such as ESP-IDF and Arduino, MicroPython, real-time operating systems, the main loop, watchdogs and working with very little memory.Intermediate
  8. 08Wireless BasicsThe radios IoT devices use and their trade-offs: Wi-Fi, Bluetooth Low Energy, Zigbee, Thread and Matter, LoRaWAN, and cellular NB-IoT and LTE-M, compared on range, power, bandwidth and cost.Beginner
  9. 09MQTT and IoT MessagingHow devices send data: the MQTT publish-subscribe model, brokers, topics and wildcards, quality of service, retained messages and last will, securing MQTT, and alternatives such as CoAP and HTTP.Intermediate
  10. 10Smart Meters and the P1 PortThe Dutch smart meter as a worked example: what it measures and sends, the DSMR P1 port and its telegrams, reading and checking a telegram, and the privacy rules around meter data.Intermediate
  11. 11Edge Computing and GatewaysProcessing data near the devices: what gateways do, protocol translation, filtering and buffering at the edge, store and forward, and when to compute at the edge or in the cloud.Intermediate
  12. 12IoT Platforms and the CloudManaging many devices from one place: IoT platforms, device registries, device twins and shadows, digital twins, rules and data pipelines, and the trade-offs of cloud platforms versus self-hosting.Intermediate
  13. 13Provisioning and Over-the-Air UpdatesGetting devices into service and keeping them up to date: device identity and certificates, provisioning at scale, over-the-air updates with A/B partitions and rollback, and decommissioning.Intermediate
  14. 14IoT SecurityWhy IoT devices are attacked and how to protect them: default passwords and botnets, secure boot and signed firmware, encrypted communication, ETSI EN 303 645, product security law per region, and segmenting IoT networks.Intermediate
  15. 15IoT Data: Time Series and StreamsHandling the data devices produce: time series and timestamps, sampling and aggregation, gaps and late data, time-series databases, retention and downsampling, and data quality at the source.Intermediate
  16. 16Smart Home and Building AutomationIoT where people live and work: smart home hubs and Home Assistant, Matter and Thread, building management systems and BACnet, energy management with solar panels, batteries and dynamic tariffs.Beginner

IoT & Embedded Systems glossary

Short definitions of the terms used in this topic. The full glossary covers every topic.