This document discusses requirements and considerations for creating Internet of Things (IOT) edge nodes using microcontrollers. It provides an overview of microcontroller vs microprocessor differences, popular low-power radio technologies like LoRaWAN, development environments like Arduino and Mbed, interfaces for connecting sensors, and an example of creating a weather sensor node with a BME280 environmental sensor and LoRaWAN radio module.

1. Living On the IOT Edge
Steve Mylroie
Roietronics

3. Overview
• IOT Edge Node Sensor Requirements
• Micro Processor vs Micro Controllers
• Micro Controller Development Environments
• Low Power Radio Overview
• LoRaWAN
• Things Network
• Sensor Interfaces
• Creating an IOT Weather Sensor

4. IOT Edge Node Sensor Requirements
• Low Power
• Wireless Connectivity
• Multiple Types of Sensor Interfaces
• Low Cost
• Low Deployment Cost
• Low Support Cost
• Security
• Over the Air Update*

5. IOT Data Collection
CloudSensors Micro
Controller
Gateway
Azure IOT Suite
AWS IOT
IBM Bluemix
G.E. Predix
Internet
MQTT
AMQP
HTTPS
IP6
?
Sigfox
LoRaWAN
Bluetooth
ZigBee
Thread
WiFi
Cellular
Digital I/O
Analog I/O
I2C
SPDI
One Wire
FieldBus
Serial
CAN
SDI-12
ARM CPU
SDRAM
NVRAM
A/D(s)
UARTS
Timers
Counters
GPIO
Radio ?
Micro Controller Vendors
Ti, Atmel, ST, Renesas, Nordic Semiconductor, Microchip, Intel, NXP, Silicon Labs, Nuvoton

6. Micro Processors vs Micro Controllers
• High Speed Clock
• Wide Data & Address Buses
• Large Dynamic Off Chip Memory
• Off Chip IO Controllers
• Complex Operating Systems
• High Power Consumption
• Limited Sleep Options
• Large Off Chip Non Volatile
Memory
• X86/SPARK/IBM/ARM Ax
• Low Speed Clocks
• Narrow Data & Address Buses
• On Chip Memory (Static & Flash)
• On Chip IO Controllers
• Simple or No Operating Sytems
• Low Power Consumption
• Fast Enter/Exit Low Power Sleep
• Pin Matrix
• Multiple Counter/Timers
• Arm Cortex Mx

7. Micro Controller
Development Environments
• Proprietary (C/C++) Local
• Arduino
Processing - C++/C Local
Single Thread - Open Source – Multiple Controllers
Mbed
C++/C Local/Web
Multi-Thread – Real Time
Open Source Multiple Controllers
PyXXX
Micro Python

8. Low Power Radio Technologies
• BLE Blue Tooth Low Energy – Open
• Sigfox -- Closed
• LoRaWAN – Open
• LTE-M – Closed
• LTE-NB – Closed
• Zibee – Open
• Next – Open ?

9. Radio Frequency Bands
• Unlicensed – ISM (Industrial, Scientific, Medical)
• 900-866-433 MHz LoRaWAN, Sigfox, Zigbee
2.4 GHz WiFi, Bluetooth, Zigbee, Others
• 5 GHz WiFi 2
• Likened
• Cell Phone Service Provider
• License/Legal Issues
• Type Approval
• On Premise

10. LoRaWAN Modes
Class A Node (Low Power)
• Node initiates session by transmitting to Gateway
• Gateway send reply on same channel after 1 Second
• If no ack sent by node second reply on standard
designated channel at 2 seconds after transmission
• Replay can contain data payload
• Most available module are Class A nodes
Class B Node (Beacon)
• Node and Gateway exchanges periodic messages to
keep clocks synchronize
• Message can contain data payloads
Class C Always On
• Both node and gateway always listening
• Highest Power consumption

11. LoRaWAN Channels

12. Thing Network Project
• Project Page
• https://www.thethingsnetwork.org/ -
• https://www.thethingsnetwork.org/map
• Kickstarter Hardware Page
• https://shop.thethingsnetwork.com/

13. Programing a LoRaWan Module
1. Serial Commands
1. AT style Multi-Tech Systems
1. AT#W=
2. AT$S=data_value
2. Private command set Microchip
1. A
2. B
2. C++ API Multi-Tech Systems
1. MBED Web ARM development environment
2. MBED Offline development environments
3. C++ STM
1. Private IDE
4. Micro Python PyCom (LoPy, FiPy)

14. Code Example
• Sensor to Gateway
• I2C bus Sensor (BME280)
• Interrupt Driven Sensor (Rain Gauge)
• Multi-Tech mDot
• Using Mbed online Development environment
• Mbed-OS https://github.com/ARMmbed/mbed-os/
• libmDot-MBed5
https://developer.mbed.org/teams/MultiTech/code/libmDot-mbed5/

15. Sensor Interfaces
• Digital I/O
• Analog I/O
• I2C
• SPDI
• One Wire
• FieldBus (Mod Bus)
• Serial
• CAN
• SDI-12

16. Tilting Bucket Rain Gauge
Professional Version Example http://static.davis.com/large_images/99800_50.jpg

17. BME280
• The BME280 is an integrated environmental sensor developed
specifically for mobile applications where size and low power
consumption are key design constraints. The unit combines
individual high linearity, high accuracy sensors for pressure,
humidity and temperature in an 8-pin metal-lid 2.5 x 2.5 x 0.93
mm³ LGA package, designed for low current consumption (3.6 μA
@1Hz), long term stability and high EMC robustness.
• The humidity sensor features an extremely fast response time
which supports performance requirements for emerging
applications such as context awareness, and high accuracy over a
wide temperature range. The pressure sensor is an absolute
barometric pressure sensor with features exceptionally high
accuracy and resolution at very low noise. The integrated
temperature sensor has been optimized for very low noise and
high resolution. It is primarily used for temperature
compensation of the pressure and humidity sensors, and can also
be used for estimating ambient temperature.
• The BME280 supports a full suite of operating modes which
provides the flexibility to optimize the device for power
consumption, resolution and filter performance."

18. References
Standards and Tools
1. Sigfox http://www.sigfox.com/
2. LoraWAN https://www.lora-alliance.org/
3. Bluetooth https://www.bluetooth.com/
4. Zigbee http://www.zigbee.org/
1. Arduino https://www.arduino.cc/
2. Mbed https://www.mbed.com/en/
3. Things Network https://www.thethingsnetwork.org/
Azure IoT Suite https://www.microsoft.com/en-us/cloud-
platform/internet-of-things-azure-iot-suite
AWS Iot https://aws.amazon.com/iot/
IBM Bluemix https://console.ng.bluemix.net/

19. References Modules
1. Loran Modules – North America
1. Multi-Tech Systems
1. Mdot http://www.multitech.com/brands/multiconnect-mdot
2. Xdot http://www.multitech.com/brands/multiconnect-xdot
3. STM32F411RET http://www.st.com/content/st_com/en/products/microcontrollers/stm32-32-bit-arm-cortex-
mcus/stm32f4-series/stm32f411/stm32f411re.html
4. ST32L151CCU6 http://www.st.com/content/st_com/en/products/microcontrollers/stm32-32-bit-arm-cortex-
mcus/stm32l1-series/stm32l151-152/stm32l151cc.html
2. STM
1. http://www.mouser.com/new/stmicroelectronics/stmicro-stm32-lorawan-discovery-board
2. http://www.mouser.com/new/stmicroelectronics/stmicro-stm32-lora-extension-board
3. PyCom (LoPy & FiPy) https://pycom.io/hardware/
2. Microchip Sigfox Modules – North America
1. TD Next http://rfmodules.td-next.com/modules/td1508/
2. Radiocrafts http://radiocrafts.com/index.php?sideID=700
3. Atmel http://www.atmel.com/products/Wireless/sigfox/sigfox.aspx
4. Ti http://processors.wiki.ti.com/index.php/Sigfox_SDK_Demo_User%27s_Guide
5. M2COMM http://www.m2comm.co/frontpage/portfolios/wireless-module-sigfox/uplynx-rcz24/
6. MICROCHIP http://www.microchip.com/wwwproducts/en/RN2903
7. PyCom (SiPy & FiPy) https://pycom.io/hardware

20. Module References 2
1. Zigbee
1. Digi https://www.digi.com/products/xbee-rf-solutions/rf-modules/xbee-
zigbee
2. List CALIBEX http://www.calibex.com/Zigbee-Modules/shop-
html?nxtg=ce40a1c0504-BABA93FF7D582E1
2. Bluetooth
1. RfDuino http://www.rfduino.com/
1. Nordic RF51 https://www.nordicsemi.com/eng/Products/nRF51-Series-SoC
2. Simblee https://www.simblee.com/
3. Nordic RF5282 http://www.nordicsemi.com/eng/Products/Bluetooth-low-
energy/nRF52832

21. Reference Other
• Iot Platform as a Service
– G.E. Predix https://www.predix.com/
• Wireless Protocol List
http://www.link-labs.com/complete-list-iot-network-protocols/
• http://www.lairdtech.com/products/rm1xx-lora-modules?language=en
• http://www.cisco.com/c/en/us/products/collateral/se/internet-of-
things/datasheet-c78-737307.html
• https://www.loriot.io/lora-gateways.html
• Protocol Business Case Ananlsys
– http://www.nickhunn.com/lora-vs-lte-m-vs-sigfox/

22. Mbed 5.0 URLs
• Home
– https://os.mbed.com/
• Compiler
– https://os.mbed.com/compiler
• Git Hub Mbed Source
– https://github.com/ARMmbed/mbed-os/
• Sample Code
• https://os.mbed.com/users/Roietronics/code/CodeCampDemo