What is IoT?


Understanding and working with sensors and wireless communication

1. What is IoT?


IoT is short for "the Internet of Things". Although it may be difficult to imagine from these words alone, we can deepen our understanding by looking at usage cases and components that make up IoT.

1-1. The Concept of IoT

IoT refers to the broad network of interconnected devices embedded with sensors and software for the purpose of transferring and sharing data over the internet. This allows information (data) collected from physical objects to be stored on dedicated servers or in the cloud. Analyzing this accumulated information makes it possible to achieve a safer, more convenient society by providing optimal device control and methods.

1-2. Practical Applications of IoT

Now that we have explained the concept of IoT, let’s look at areas where it is already in use. Below are 3 examples.

1-2-1. Smart Homes: IoT + Consumer Electronics

A smart home is a home that uses IoT to provide greater convenience and security. For example, home appliances can be connected to the internet and controlled through human interaction (voice, smartphone app), while attaching sensors enables automated control to deliver unprecedented levels of comfort and convenience.

Specifically, IoT can be utilized to achieve the following.

  • Turn on/off the AC and lights and lock/unlock doors with a smartphone app
  • Monitor daily electricity usage and optimize the AC temperature and light settings to cut costs and adapt to user needs
  • Incorporate sensors to turn on/off lights automatically when entering/exiting the room

1-2-2. Smart Cities: IoT + Cities

Smart cities are cities that adopt IoT to achieve greater energy savings while minimizing environmental impact. The concept of smart cities has changed with the times, but at the moment, many cities are installing multiple sensors to acquire data on environmental conditions and consumer behavior as well as enable remote control of equipment and facilities to optimize operations and improve convenience for residents.

Specifically, IoT can be utilized to achieve the following.

  • Detect and monitor the flow of people based on location information (i.e. using smartphone GPS)
  • Adjust city lights to the optimum brightness by measuring traffic volume
  • Facilitate parking and ease congestion by monitoring and displaying parking space availability

1-2-3. Connected Cars: IoT + Cars

Connected cars are cars that incorporate IoT to achieve safer, more comfortable driving. By acquiring and analyzing driving data obtained through onboard GPS, sensors, and cameras together with information on surrounding traffic it is possible to achieve safer driving control and provide optimal traffic guidance.

Specifically, IoT can be utilized to achieve the following.

  • Achieve autonomous driving (*fully autonomous to be covered in a future story)
  • Track vehicle location (i.e. in the event it is stolen)
  • Check tire pressure and maintenance information using a smartphone app
  • Use your smartphone to remotely control the AC and lights even when not in the vehicle

1-3. Key Elements of IoT

IoT is comprised of 4 main elements: devices, sensors, networks, and applications.

Devices Refers to physical objects (things) people use,
such as the above-mentioned smartphones, appliances,
city equipment/facilities, and cars.
Sensors Components embedded in devices to measure ambient conditions/phenomena.
Examples include sensors that detect changes in the environment
(e.g. temperature, humidity, pressure, light, and geomagnetic field)
as well as motion such as acceleration and sound.
Networks A means of communication for sending data acquired by sensors to terminals
(i.e. cloud servers and smartphones).
Wireless communication such as Wi-Fi is generally used.
Applications Sets that enable visualization of data obtained from sensors.
This typically includes PCs and smartphones.

The operating flow involves first acquiring data from sets equipped with sensors and wireless devices before sending the data to servers and the cloud through the internet for storage and analysis. Next, the data is visualized in an application, providing a general framework for optimizing set usage. The mechanism is shown in the following diagram.

It is the structure of the large frames to optimize the usage of the device

In the next chapter we will cover the sensors and wireless communication methods essential for acquiring data in devices and constructing wireless networks.

2. Sensors for Detecting Various Conditions

Sensors are used to detect various situations. They can be broadly classified into 2 types, field sensors that measure environmental conditions and motion sensors for detecting movement.
Field sensors include temperature and brightness sensors, for example, that can measure external temperatures and light intensity, while motion sensors such as accelerometers measure changes in object movement (i.e. tilt and vibration).

2-1. Typical Sensor Types and Applications

Below is a table listing the names, types and application examples of typical sensors.

Sensor Type Purpose Application Examples
Gyro (Angular Velocity)
Measure changes
in object movement
(i.e. tilt, vibration, rotation)
(e.g. drive recorders, smart keys)
Industrial (motors, robots, etc.)
Measure the Earth’s
magnetic force to
determine direction
Communication devices
(such as smartphones)
Wearables (i.e. smartwatches)
Measure the pressure
of a gas or liquid
Wearables (i.e. watches)
Health & fitness
(activity monitors, etc.)
Measure temperature Room/ambient
temperature monitoring
Measure light intensity Communication devices
(such as smartphones)
Detecting sunlight, etc.

3. Wireless Communication Networks for IoT Devices

Wireless communication is needed to connect devices to the internet.

3-1. Overview and Mechanism of Wireless Communication

Wireless communication is a method for sending information using electromagnetic waves or light (infrared) without the use of wires. Since electromagnetic waves are transmitted through the air over a wide range, they have been primarily used for commercial communication such as TV and radio. In recent years, however, wireless communication has been adopted for personal use in the form of Wi-Fi and Bluetooth® for smartphones and PCs.
In the IoT sector, much attention is being paid in the field of ‘short-range wireless communication’, with technical application expected to follow. In the next section we will introduce the different types of short-range wireless communication.

3-2. List of Communication Standards

Several standards for wireless communication exist. Here we will take a look at the 4 main bands - Bluetooth®, Wi-Fi, EnOcean, and Specified Low Power Wireless Communication (Wi-SUN) - comparing the frequency bands, communication range, and transmission speed while listing application examples.

The table below summarizes the primary features of the four standards.

  Bluetooth® Wi-Fi EnOcean® Specified
Low Power
~10m Hundreds
of meters
~200m ~1km
1Mbps~ 11Mbps~ 125kbps ~9600bps 50kbps~
Remote controls,
PC peripherals,
consumer electronics,
blood pressure monitors,
heart rate monitors,
surveillance cameras
(for controlling
Smart meters,

3-3. Regarding Radio Laws and Technical Suitability

As a precaution for wireless communication, it is necessary to understand all applicable radio laws.
Communicating using the same frequency band in the same area may cause interference. Therefore, in order to transmit wirelessly, it is necessary to obtain a radio license from the government in order to ensure fair and equal use.
In addition, under the radio law each wireless device must meet the prescribed technical standard, and verification that it conforms to this standard is referred to as the technical standards conformity certification (technical compliance).

4. Easy to Use IoT Kit Optimized for Home Projects

Thus far, we have covered sensors and wireless communication protocols that are key to understanding and configuring IoT devices. Next we will discuss IoT kits make it easier to build IoT devices, especially for those that still find it difficult to imagine the concept of IoT.

4-1. DIY IoT Devices

Let’s look at an actual example of a homemade IoT device built using a kit.

4-1-1. Multifunction voice-operated remote control

Multifunction voice-operated remote control

Shown above is a multifunction remote control with Raspberry Pi MCU board designed to turn ON/OFF various equipment by voice. The device is comprised of an MCU board, infrared LED, and voice guidance software. In the photo, the remote is used to turn ON/OFF the TV by voice, but can be registered to control AC and lighting equipment as well.

Click on the link below to learn more. (This page is only available in Japanese.)

The IoT kit allows users to design a whole range of devices and functions. Check out our Device Plus website for additional ideas.

4-2. MCU Boards and Evaluation Kits Essential for IoT

In recent years a number of MCU boards optimized for developing IoT devices have emerged, such as Raspberry Pi, Arduino, and Sony Semiconductor Solutions’ SPRESENSE™.

4-2-1. Arduino


Arduino was one of the most popular MCU boards that existed before IoT began attracting attention. Its relatively cheap price and easy startup (simply connect to a PC via USB to begin operation) make it ideal for beginners. However, Arduino does not have a native operating system (OS), and therefore requires a dedicated integrated development environment tool (IDE).
Arduino’s main areas of focus lies in equipment control (i.e. of robots), communication with PCs, and simple circuit testing.

4-2-2. Raspberry Pi

Raspberry Pi

Raspberry Pi is a well-known MCU board about as popular as Arduino. Features include both video and sound outputs, output to HDMI displays, USB, and LAN, providing functionality similar to an ultra-compact computer.
Although slightly more expensive than Arduino, it is possible to install Linux OS, making it easier to use for those familiar with this operating system. Raspberry Pi excels in areas such as configuring servers and converting electrical appliances to IoT.


SPRESENSE™ is an MCU board developed by Sony Semiconductor Solutions Corporation. Like Arduino, it has no native OS and therefore requires a dedicated IDE for development. But unlike other MCU boards, it includes GPS and high-resolution audio functions, enabling the development of sensing applications using voice, image, and position information.

4-2-4. Evaluation Kits

When developing applications and software to achieve IoT with an MCU board, it is advisable to use an evaluation kit (expansion board) for carrying out wireless communication and data acquisition from sensors.
ROHM provides evaluation kits and development tools that facilitate the development of IoT devices.

Sensor Medal
[ROHM Sensor
Evaluation Kit]
A sensor evaluation kit Ideal for beacons and wearables. geomagnetic field,
brightness, 6 sensors are built in (accelerometer, pressure, and magnetic (Hall IC)),
together with a Bluetooth® module. (Japanese page)
[ROHM Sensor
Evaluation Kit]
A sensor evaluation kit compatible with open platforms
such as Arduino Uno and mbed.
8 sensors (accelerometer, pressure, geomagnetic field, brightness/proximity,
color, and magnetic (Hall IC) are mounted on the substrate.
EnOcean A self-powered wireless communication module that transmits data using
a small amount of energy generated from the surrounding environment
(i.e. from kinetic energy, temperature differences).
Lazurite A low power MCU board integrating 920MHz wireless communication functionality.
(Kits compatible with Raspberry Pi are also available.) (Japanese page)
Add-On Board for
An add-on board that expands the functionality of the SPRESENSE™
computer board for IoT offered by Sony Semiconductor Solutions Corporation.
Adds functions for sensors along with Bluetooth®
and Wi-SUN wireless communication protocols.


Thus far, we have discussed the mechanism of IoT, provided application examples, and covered sensors and wireless communication protocols that are expected to be key to developing IoT technology in the future.
To this end, ROHM provides a number of MCU boards and IoT evaluation kits that facilitate IoT set development and prototyping. But perhaps the best way to understand IoT is to try it out firsthand, so why not give it a shot?