Data is the new oil for digital businesses, as the adage goes. So how do you capture real-time data from the physical world?

Therefore, sensors are an essential part of IoT products in many industries and require careful selection as they help to measure and control the properties of assets and facilities (environments). IoT sensors are at the first or bottom layer of the IoT stack.

Innovation leaders with business knowledge develop ideas for new products, process improvements, or ways to solve problems. Then they define the type of data needed and create an IoT use case, such as air quality, retail store occupancy, vehicle traffic monitoring, people flow, perimeter control, temperature, humidity, energy consumption, asset tracking, etc.

For example, if you want to know the temperature in all the hotel rooms and adjust it to optimize energy consumption, you must install temperature sensors. A system will ingest and analyze the data and trigger actions without human intervention.

Sensors transmit data through a communication network that connects IoT edge and gateways and goes to a platform where the data system collects, processes, and analyzes the data. Once you have the data, you can create workflows and pipelines that feed analytics systems, machine learning models, and AI applications.

IoT sensors have principles of operation that measure and detect changes in properties such as electrical resistance, capacitance, light intensity, magnetic fields, electrical signals, etc. Such changes are detected and converted to optical or electrical signals, generating an output processed by the microcontroller.

Microcontrollers convert analog signals to digital signals, such as a voltage signal to a digital value representing the data. These signals are processed to extract information, analyze, and generate an output sent to the IoT platform.

The output generated is used by other systems that perform actions, control, or interact with other devices. For example, if a factory machine malfunction is detected, this signal may stop other machines until corrections or modifications are made.

You want to capture data from IoT sensors to solve problems, save money, and/or create an innovative product. So, the system must process the signals and extract the information with a few techniques, such as filtering for removing frequency components, extracting frequency components, reducing random noise, transforming to other scales, or using algorithms to extract features and patterns (feature engineering). These techniques depend on the type of IoT sensor and the IoT application.

IoT sensors communicate through communication protocols and compatibility with the platform, manufacturer specifications, etc. Communication protocols are lower level and define how devices connect, establishing the physical and logical connection between IoT devices

• I2C (Inter-Integrated Circuit) (synchronous)
• SPI (Serial Peripheral Interface) (synchronous)
• Wireless Protocols
  • Short Range (Bluetooth, Wi-Fi, Matter)
  • Long Range (Zigbee, LoRa, Cellular)
• UART (Universal Asynchronous Receiver-Transmitter) (asynchronous)

Messaging protocols are higher-level protocols in the application layer offering defined mechanisms for exchanging messages between devices.

MQTT (Message Queuing Telemetry Transport) is a lightweight publish/subscribe messaging protocol commonly used to securely connect and share data between IoT sensors/devices, cloud computing, and applications. MQTT requires minimum bandwidth and is ideal for IoT devices with limited resources.

IoT sensors are classified as active (external stimulation) or passive, analog, or digital. A single component or a module with a built-in microcontroller measures different things, such as temperature, pressure, light, distance, etc.

IoT sensors also use different technologies, such as images, light, magnets, infrared, touch sensing, ultrasonic, sonar, and many more.

There are miniature sensors built using MEMS (Microelectromechanical Systems) that are highly sensitive and measure the physical, biological, or chemical properties of particular environments. For example, some MEMS sensors are accelerometers, gyroscopes, and pressure sensors.

Although we have mentioned some of these sensors throughout this paper, you can see a curated list of the top IoT sensors below:

1. Pressure sensors
2. Temperature sensors
3. Image sensors
4. Gas Sensors
5. Humidity Sensors
6. Optical Sensors
7. Proximity Sensors
8. Motion Sensors
9. Infrared (IR) Sensors
10. Smoke Sensors
11. Gyroscopic sensors
12. Acceleration sensors
13. Chemical sensors
14. Water quality sensors
15. Level sensors

Krasamo is an IoT development company based in Plano, Texas, with more than 12 years of experience in IoT projects in industrial and consumer markets.

Krasamo serves the IoT technology market and has participated in strategic developments collaborating with many medium to large US clients.

Learn more about IoT consulting services with Krasamo today.