Getting started with IoT

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Microcontrollers, edge and
embedded computing
A microcontroller is an integrated chip that contains a
processor (CPU), memory and interfaces to communicate
with sensors. These are typically used in IoT devices.
A processor acts as the brain of the IoT device. Depending on
the application, this can simply read the sensor data and pass
it to the communications module, or it can perform more
powerful edge processing tasks.
A microcontroller provides
the ability to:
• Interface with one or more sensors and extract the data
• Control something, e.g., switch or unlock an item such
as a valve or a fan
• Perform processing on this data
• Transmit this data over a wired or wireless network
• Receive instructions over the network from the
application and execute these instructions.
• Control power consumption of the IoT device
The responsibilities required of the microcontroller will
depend on the nature of the project. It is the role of a
firmware engineer to develop the necessary firmware of
the microcontroller so it can carry out the tasks required.
Return to
a sleeping
state
Listen for any
incoming
instructions from
the application and
execute these if
found
Remain in a
sleeping state
most of the time
to conserve
battery life
8
1
Edge node
process flow
7
Wake from a
sleeping state for
an event or an
alarm
2
6
Interface with the
communications
module to send the
data packet over the
network
3
5
Take readings (data)
from a sensor(s)
4
If required,
carry out
some form of
processing on
this data
Package the
data into a
format suitable for
sending over the
communications
network
Criteria for microcontroller choice
• Power consumption: Effective performance and long
battery life at the lowest possible cost.
• Ability to support any interfaces required by the
application.
• Performance need: IoT devices typically use low
performance microprocessors (sleeping most of
the time). If more pre-processing of the data is
required, a mid-range performance microcontroller
will be needed.
• Onboard memory component requirement:
If it is more useful to log data in batches and only
send at an appropriate time or when there is a signal,
onboard memory components will allow the
developer to store records of data that will remain
when the device is powered down.
• The preference of the development environment.
• Package size, reliability and ease of replacement
• Required functionality of software and technical
support from vendor.
Choosing a development platform
Microcontroller manufacturers offer hardware development
platforms for their devices. These electronic boards allow
engineers to quickly develop firmware for their products
without first having to develop any hardware. They also provide
a good example of the hardware required to support the
device. This can help the hardware engineer when it comes to
designing a custom board. Vendors will often provide source
schematics and PCB layout files (Altium, OrCad, Eagle) to aid
the development of custom/bespoke hardware and shorten
time to market.
For devices designed with IoT in mind, their development
platforms will often include various sensors integrated directly
on to the board, as manufacturers expect most engineers will
use their device to integrate with sensors.
Development boards are constantly evolving to include the
latest technology, especially in a rapidly evolving IoT market.
Some examples of popular development platforms are:
• Thunderboard Sense 2
• MangOH
• Arduino & Shields
• Particle.io
• Raspberry Pi
• ESP32 & ESP8266
• MSP430
• STM32 family
When developing commercial hardware, products must have
the relevant approvals and certification (EMC, safety, radio) in
place before being offered for sale.
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