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Practical introduction to IoT
- 1. Introduction to practical IoT Pekka Nikander, Aalto University June 1st, 2018
- 2. Today’s outline • Introduction to Internet of Things (60 slides, 90 min) • NEPPI IoT (20 slides, 30 min) • NEPPI Tech Tools (10 slides, 15 min) • NEPPI Tech Roles (discussion)
- 3. NEPPI Tech Course • NEPPI Tech is a new IoT course at Aalto university • Goal: learn to make simple IoT devices • All aspects: HW, powering, SW, communication • Teamwork, with different roles • Practical goal: Make a simple BLE device and integrate with an external “gateway” system • https://neppi.aalto.fi/about/ • https://github.com/AaltoNEPPI
- 4. Introduction to Internet of Things Pekka Nikander, Aalto University June 1st, 2018
- 5. Outline • Overall IoT system architecture • What a “real” IoT system architecture would be • The simplified architecture used at NEPPI • Embedded or “thing” devices • User interfaces options and the NEPPI approach • Understanding the cloud and communications • Future directions
- 7. IoT system architecture PC Smartphone / tablet PaaS / serverless RasPi / dedicated Embedded Communication
- 8. NEPPI system architecture Smartphone Linux nRF52 embedded (Arduino) HTTP / HTML5 BlueTooth Low Energy USB / serial Framework7 Unity3D
- 9. Outline • Overall IoT system architecture • Embedded or “thing” devices • Estimating the total cost & feasibility • Hardware & Software • User interfaces options and the NEPPI approach • Understanding the cloud and communications • Future directions
- 11. Estimating the total cost • Development costs • Hardware design: PCB, assembly, testing • Software design: Design, coding, testing • Casing and mechanical design • Manufacturing costs • BOM: Bill of Materials: electronics & mechanics • Manufacturing costs: assembly, testing, packaging • COGS: Cost of Goods Sold
- 12. Thing HW considerations • Real life interfaces: sensors, actuators • Computation needs: logic, protocols, security • Communication: wireline, wireless • Power: wireline, battery, charging • Total cost: Development, BOM, COGS • BOM: Cost of parts, assembly • COGS: Manufacturing, defect products, support
- 13. Estimating hardware cost Cheapest Wearable BLE RasPi Wifi MCU Comms PSU Battery PCB + misc Total ? ? ? + sensors Note! Numbers will be educated guesses! Focus
- 14. Estimating power Battery Electrical capacity ?? mAh Max current ?? mA Power supply MCU Radio Others Voltage regulation Peak and average power consumption ? mA ? V ? mA ? mA ? V Battery life = battery capacity / average consumption
- 15. Where to get the numbers? • Different channels for sourcing components • Digikey for single components and prototypes • Farnell, Mouser etc. for larger numbers • Adafruit and Sparkfun for prototyping boards • Component costs vs. volume: a rule of thumb • Increasing volume 10x lowers the unit price 20% • Experience teaches you to guess
- 16. Three Cs • Connect • Connect locally with the real world • Compute • Perform (relatively) complex operations • Communicate • Communicate through the Internet
- 17. A typical “thing” MCU CPU SRAM Flash memory Comms I2C SPI GPIO … Sensor Actuator Sensor Power supply Antenna -or- cable driver (PHY) Connect Compute Communicate
- 18. Compute • Local application logic • Pre-process data, local control loop, … • Communications • Upper protocol layers, energy saving features • Security • Certificates, crypto keys + algorithms, protocols
- 19. Compute alternatives • MCU: Micro Controller Unit • A tiny computer: CPU, SRAM memory, Flash • FPGA: Field Programmable Gate Array • Programmable logic gates • ASIC: Application Specific Integrated Circuit • Custom designed chip
- 20. MCU / FPGA / ASIC MCU FPGA ASIC Availability COTS COTS Custom Development Easy Harder Hardest Performance Slow Faster Fastest Power Highest Depends Lowest Size Large Large Small Upfront cost Low: 1k+ Medium: 10k+ High: 500k+ Unit cost Medium: 0.50–50 High: 5–200 Low: 0.01–5
- 21. Example low end chips STM 32F030 nRF52832 ICE40LP8 ECP3-17 CPU Cortex-M0 Cortex-M4F FPGA FPGA SRAM 4 kb 32 kb 16 kb 90 kb Flash 16 kb 256 kb 7680 LUT 17 kLUT Performance 43 MIPS 80 MIPS ~10 ns ~5 ns Powering 3.3V 1.8–3.3V 1.2V 1.2V Consumption 20 mA 10–50 mA < 20 mA > 100 mA Cost @1 $1 $4 $7 $25 Since 2015 2016 2013 2012
- 22. Connect: Sensing and actuating • Sensing the environment • Hundreds of possibilities: temperature, light, noise, humidity, orientation, movement, … • Usually implemented with a separate chip • Actuating • Lighting, voice, vibration, movement, … • Usually need a separate driver chip or circuit
- 23. Some sensors examples Light sensor Gyroscope GPS Sensing Ambient light Direction, movements Outdoor location Example AMS TSL2571 STM L20G2 Venus638FLPx Powering 3.3V 1.8V, 3.3V 3.3V Consumption 170 μA 1.4 mA 50 mA Interface I2C SPI I2C, SPI, UART Cost @1 $0.70 $2.20 $40
- 24. Communicate • Talk with the rest of the system • Basic alternatives: wireline or wireless • Wireline allows integrating power delivery • Wireless is sometimes cheaper but less reliable • Wireless the only choice for mobile devices
- 25. Wireline alternatives USB (Type C) Ethernet 802.3 PoE 802.3at PoDL 802.3bu PLC (Homeplug) Max bps 10 Gb 1 Gb 1 Gb typ. 10 Mb (802.3cg) 500 Mb Latency Low Low Low Lowish High Max length < 5 m 100 m 100 m 200 m or 1 km ~50 m Cable USB specific 4 pairs UTP 4 pairs UTP 1 pair UTP AC power Max Power 100 W – 50–90 W 65 W > 1 kW Cost ~$10 $2–10 ~$10 < $1 ? ~$40 Since 2016 1980s 2009 2018 2010
- 26. Some wireless alternatives WiFi 802.15.4 BLE NB-IoT Typical speed 150 Mbps 250 kbps 1 kbps 20 kbps Latency 2 ms varies 1 s 2–10 s Distance 100 m 10 m 10 m 10 km Freq ISM 2400 or 5000 ISM 900 or 2400 ISM 2400 4G licensed Power 1W 100 mW 10 mW 500 mW Cost @1 $5 Builtin Builtin $10 Since 1990s 2006 2010 2018
- 27. A typical “thing” MCU CPU SRAM Flash memory Comms I2C SPI GPIO … Sensor Actuator Sensor Power supply Antenna -or- cable driver (PHY) LiPo battery
- 28. Estimating power Current Cheapest PoDL Wearable BLE RasPi Wifi MCU 20 mA 20 mA 500 mA Comms 50 mA 30 mA 300 mA Max current 70 mA 50 mA 800 mA Battery capacity – 500 mAh 4000 mAh Sleeping time 90 % 96 % 90 % Battery life — 75 h 50 h
- 29. Powering examples CR3032 battery Rechargeable LiPo battery PoDL 802.3bu Picture Nominal voltage 3V 3.7V 12V or 48V Capacity 210 mAh (e.g.) 500 mAh No limitation Std current 0.2 mA 100 mA N/A Max current 15 mA 500 mA typ. > 1000 mA Weight 7g 10g N/A PSU cost $1 $5 ?? (not available yet) Battery cost $2 $8 –
- 30. Estimating hardware cost Cheapest PoDL Wearable BLE RasPi Wifi MCU 0.50 3.00 7.00 Comms 1.50 (IC + isolation) 1.00 (antenna etc) 5.00 (Wifi module) PSU 2.00 (IC + isolation) 2.00 (charger + coil) 4.00 (charger + coil) Battery – 4.00 8.00 PCB + misc 1.00 1.00 4.00 Total @10k 5.00 11.00 28.00 Note! Numbers are educated guesses for a lot of 10k!
- 31. Rough relative cost Power 50 % Comms 38 % MCU 13 % Power 60 % Comms 10 % MCU 30 % Power 50 % Comms 21 % MCU 29 % Cheapest PoDL Wearable BLE RasPi WiFi (battery powered) Powering matters!
- 32. Outline • Overall IoT system architecture • Embedded or “thing” devices • Estimating the total cost & feasibility • Hardware & Software • User interfaces options and the NEPPI approach • Understanding the cloud and communications • Future directions
- 34. Thing SW considerations • Remember: really small memory • Flash: 16 kb — 1024 kb • SRAM: 4 kb — 256 kb • Memory is a major cost factor for the MCU • Not even a remote possibility to run Linux • Choices: Bare metal or RTOS
- 35. Bare metal • Program directly on the top of hardware • Maybe a “HAL” (hardware abstraction layer) • No dynamic memory management • No multitasking: no processes, no threads, nothing • Choices: Polling, interrupts, custom scheduler • Must tackle the parallelism present in hardware • Many I/O functions work autonomously
- 36. Real Time OS • Dozens of different ones available • Complexity and features vary a lot • Complexity also affects memory cost • Most popular ones today open source • Pay attention to community, licence, ownership • FreeRTOS, RIOT-OS, Contiki, mbed, Brillo • At NEPPI we use RIOT-OS by default
- 37. IoT RTOS comparison Contiki RIOT-OS FreeRTOS TinyOS Owner Community Community Amazon* Community License BSD LGPL MIT BSD Min SRAM 10 kb 1.5 kb 500 b 400 b Typ. SRAM 30 kb 5 kb 2 kb 1 kb Min Flash 30 kb 5 kb 10 kb 1 kb “Forks” 2200 1000 160 400 Status Active Active Active Waning out Since 2003 2013 2003 2000 * Amazon bought FreeRTOS in 2017
- 38. Typical SW architecture MCU CPU Hardware abstraction layer Radio I2C SPI GPIO… Interrupts SchedulerSerial driversRadio driver Sensor drivers Comms protocols GPIO Application
- 39. Software challenges • Power consumption • Device should sleep most of the time • Both HW and SW should be considered • Concurrency • Sensors and actuators work independently • Testing and debugging • Stability
- 40. Application Interrupt handlers Typical app structure SchedulerDrivers Comms protocols Main loop Worker tasks Worker tasks Interrupt handlers Statically allocated global data
- 41. SW development costs • Typically agile methods used • Hard to estimate exact final cost beforehand • Typical MCU apps: 6–36 man months • Software architecture matters • Try to keep it as simple as possible (KISS) • Study open source, search for good examples • Latent and late obscure bugs cost most • Swat bugs early, aim for zero bug toleration
- 42. Outline • Overall IoT system architecture • Embedded or “thing” devices • User interfaces • Typical IoT user interfaces • Approach at NEPPI • Understanding the cloud and communications • Future directions
- 43. User interfaces GUI Embedded UI
- 44. Main UI options • Embedded, part of a building or environment • E.g. light switch, burglar alarm control, etc. • Mobile • Smartphone app or a separate device • Web enabled, served from the cloud • Web UI, usable from PC and smartphone • Not much focus on NEPPI, more a sideline
- 45. Embedded • Traditionally custom-designed • Nowadays more and more one of the following: • Raspberry Pi with a small (touch) display • Android tablet in a custom casing • One of the emerging embedded platforms: Arduino, mbed, Android Things, … • Fixed installation power consumption not an issue • The price of the PSU and cabling still matters
- 46. Embedded UI @ NEPPI • You are on your own • No support from the course • Recommended: • Arduino • RasPi + Linux + Display • Either with USB power • Mind the cable lengths
- 47. Mobile UI • Smartphone app • Harder to develop & install • Works without Internet connectivity • Can use all sensors and e.g. Bluetooth • Web-based mobile UI • Easier to develop, no installation • Requires Internet (or local server) • Restrictions on using Smartphone functionality
- 48. Mobile UI @ NEPPI • Web-based mobile UI • Recommended: Framework 7 • Served from a local server • Server runs inside Unity3D • Connectivity: • 3G/4G cellular Internet • Local high speed WiFi
- 49. Cloud web UI • Web UI served from a cloud server • Often both mobile and tablet/PC adaptions • Often shows near real time data from sensors • Evolving area, no clear market leaders yet • Most popular prototyping framework: • Node RED • Not considered at NEPPI
- 50. Outline • Overall IoT system architecture • Embedded or “thing” devices • User interfaces • Understanding the cloud and communications • Cloud only very briefly • Comms: Options, protocols, Bluetooth LoW Energy • Future directions
- 52. IoT cloud • Storage and computation taking place in the cloud • Emerging field, no clear market leaders • Heavyweights rushing in: IBM, Amazon, Google, … • No clear open source platform leaders yet • EU pushes FIWARE, but it is not very good • At NEPPI we use a local Linux instead of a cloud
- 53. Communications • Local vs. Internet communications • Local: Between the “thing” and the gateway • Internet: All the rest • Wireline vs. wireless communications • Covered briefly already earlier • Protocol stacks: Internet, BLE, others
- 54. Local communication • Thing to gateway • Wireline: Ethernet, USB, PoE, others; legacy • Remember power and its cost! • Wireless: BLE, ZigBee (802.15.4), WiFi, others • Remember power and battery lifetime
- 55. Protocol stacks • TCP/IP • Used everywhere in the Internet; often also locally • Assumed to be known to everybody • USB: Own, complex protocol stack • Many subprotocols, including “serial emulation” • Also Ethernet over USB (several variations), supporting TCP/IP • BLE: Own, complex protocol stack • Main protocol: GATT (Generic ATTribute Profile) • Also TCP/IP over BLE (RFC 7668)
- 56. Bluetooth Low Energy (BLE)
- 58. Outline • Overall IoT system architecture • Embedded or “thing” devices • User interfaces • Understanding the cloud and communications • Future directions
- 60. IoT future directions • Things: • All things using electricity connecting to the Internet • PSU cost probably a major limiting factor • Target cost: < $3 with the PSU and casing • Gateways: • Hopefully standardisation and consolidation • RasPi as the de facto platform • RasPi 3 has built-in BLE and WiFi • Target cost: < $15 with the PSU and casing
- 61. IoT future directions • Cloud: • Edge and Fog computing • Network Function Virtualisation (NFV) • Computation at the network closer to the 4G/5G devices • Hopefully standardised IoT interfaces at some point • E.g. W3C Web of Things (WoT) • Artificial Integration and Big Data integration • Communication • Ethernet (for PHY) and TCP/IP as the de facto standards • USB, BLE, IoT-NB, etc as specialised local / last mile • Security more and more importan
- 62. IoT future directions • User interfaces • Smartphone increases, consolidation in embedded platforms • Security and privacy • Increasingly important • Major factor for R&D costs • Integration with blockchains aka Distributed Ledger Technologies • Data markets • Rise of Digital Twins • Possibly Open Digital Business Platforms with DLT
- 63. Summary • Overall IoT system architecture • Embedded or “thing” devices ⇐ focus here • User interfaces • Cloud and communications • Future directions
- 64. IoT system architecture Gateway Sensor Sensor Actuator PC Smartphone / tablet PaaS / serverless RasPi / dedicated Embedded Communication Cloud
- 65. IoT teaching focus Linux nRF52 embedded BlueTooth Low Energy
- 66. NEPPI IoT Pekka Nikander, Aalto University June 1st, 2018
- 67. NEPPI approach • NEPPI provides a partial, simplified IoT platform • Development boards for HW • Skeleton code for SW • Other tools may be freely used • No support from the course personnel • Recommended that you specialise! • E.g. embedded HW, SW, UI, communication, …
- 68. Course IoT architecture Smartphone Linux nRF52 embedded (Arduino) HTTP / HTML5 BlueTooth Low Energy (USB / serial) Framework7 Unity3D
- 70. Mapping the structure Linux nRF52 (Arduino)
- 71. Demo Demo of the current functionality
- 72. NEPPI components • Things: nRF52 Development Kit + RIOT-OS • User interfaces: Unity3D, Mobile Web app • Communication: BLE GATT, TCP/IP HTTP • Gateway + cloud: PC + Linux + Unity3D
- 73. Embedded Smartphone Linux nRF52 embedded (Arduino) HTTP BlueTooth Low Energy USB / serial (Framework7) Unity3D
- 74. Nordic Semi nRF52 • Very popular Bluetooth capable wireless MCU • 32-bit ARM Cortex-M4F CPU • Up to 512kB Flash • Up to 64kB SRAM • Embedded 2.4GHz radio • Internal power supply unit • Designer friendly • List price USD 1.50 – 6.00
- 75. nRF52
- 76. RIOT-OS • Popular open source RTOS • Many developers at Freie Universität Berlin • Supports programming in C (and partially C++) • Can be debugged inside a Linux process (“native”) • nRF52 BLE support experimental • Alternative: 6LoWPAN IPv6 (needs further study)
- 77. UI Smartphone Linux nRF52 embedded (Arduino) HTTP BlueTooth Low Energy USB / serial (Framework7) Unity3D HDMI
- 78. Unity 3D • Cross-platform game engine • Runs under Windows, Linux, and Mac OS X • Generates directly the 3D graphics from Linux • Supports “scripting” in C# (and Unity JavaScript) • Able to run “background tasks” — both WIP • Web server for a Mobile Web UI • BLE communication for nRF52 “things”
- 79. Mobile Web App • Served from the local Web server in Unity3D • Accessible over local WLAN (later also Internet) • Recommended UI framework: Framework 7 • Also other frameworks will be used • Only a secondary learning goal at NEPPI • Standard HTML5, supposed to be known • Support from the course somewhat lower
- 80. Communication Smartphone Linux nRF52 embedded (Arduino) HTTP BlueTooth Low Energy USB / serial (Framework7) Unity3D (HDMI)
- 81. BlueTooth Low Energy • Most commonly used low power protocol stack • Designed to work for years with CR3032 battery • Supported in all smartphones, most tablets & PCs • Most commonly used wireless in wearable devices • Requires a new GATT Profile to be defined • Programming both in Unity3D and nRF52 • Defining and implementing a major task
- 82. HTTP and HTML5 • Communication over local WiFi • Between Linux and Mobile Web app • Standard HTTP and HTML5 • Assumed to be known, e.g. from • CS-C3170 Web Software Development • CS-E4400 Design of WWW Services • CS-E4460 WWW-applications
- 83. “Cloud + gateway” Smartphone Linux nRF52 embedded (Arduino) HTTP BlueTooth Low Energy USB / serial (Framework7) Unity3D
- 84. Linux PC • Standard Linux PC running Ubuntu • Use a Virtual Machine if you run Windows • Ask for instructions from the course assistants • (Mac OS X maybe supported by the course) • Used for • Unity3D development • Compiling for and flashing nRF52
- 86. Mapping the structure Linux nRF52 (Arduino)
- 87. NEPPI Tech tools Pekka Nikander, Aalto University June 1st, 2018
- 88. NEPPI tools • Source code management tools • Programming languages and their purposes • Embedded HW development tools • Embedded SW development tools • BlueTooth development tools • Mobile Web app development tools • Locally developed tools
- 89. Source code management • The tool: git • Most popular source code management tool today • The cloud: Github • Most popular open source management platform • Tutorial on Monday June 4th • Given by Santeri Paavolainen
- 90. Programming languages • C (or limited C++) • ELEC-A7100 C programming basics • Used for nRF52 embedded coding • C# • Object oriented language, similar to Java • Used for Unity3D programming • JavaScript • Kind-of object oriented language, with its own twist • Used for Mobile Web app programming
- 91. Embedded HW tools • Nordic semi nRF52 DK • Breakout boards for sensors… • Dataloggers, oscilloscopes • Available at Sähköpaja • USB cable for powering, programming and debugging • KiCAD PCB design tool • Tutorial on June 5–6
- 92. Embedded SW tools • nRF52 SDK • RIOT-OS • Flashing tools • Linux command line • Makefiles (make) • Gnu C Compiler (gcc) • Gnu Debugger (gdb)
- 93. BLE tools • nRF Connect https://www.nordicsemi.com/ eng/Products/Nordic-mobile- Apps/nRF-Connect-for-Mobile • Downloaded app • Ubertooth https:// greatscottgadgets.com/ ubertoothone/ • Physical device, may be borrowed from Salu
- 94. Web app tools • Framework 7 http://framework7.io • New also to us; we are learning • Suitable Web debugger, e.g. • Safari: https://developer.apple.com/safari/tools/ • Chrome: https://developer.chrome.com/home/ devtools-pillar • TCP/IP protocol analyser (if really needed) • Wireshark: https://www.wireshark.org/
- 95. Locally developed tools • Unity3D Web server • https://github.com/AaltoNEPPI/uniwebserver • Unity3D Bluetooth interface • Not yet ready for release, coming • Unity3D skeleton app • https://github.com/AaltoNEPPI/Unity_NEPPI_Skeleton • All work in progress!
- 96. NEPPI roles
- 97. NEPPI Tech roles Pekka Nikander, Aalto University June 1st, 2018
- 98. Potential roles • HW developer • Embedded SW developer • BLE protocol designer & developer • Mobile Web App developer • Unity3D developer