Sensor Networks: Definition, Operation & Relationship

Instructor: Chris Farquhar

Chris is an experienced technology professional and subject matter/industry expert in AI, Internet of Things and enterprise security. He has a Science Degree (Computer Science/Information Technology).

A sensor network connects numerous sensor nodes that can detect information such as heat, pressure, and motion. With the rapid development of sensors, sensor networks are a vital part of the internet of things (IoT) and the modern world. In this lesson, we will define sensor networks, their components, their operation, implementation, and uses.

What are Sensor Networks

Today sensors are everywhere. We take these for granted, but sensors are in our phones, workplaces, vehicles, and the environment.

A sensor network comprises a group of small, powered devices, and a wireless or wired networked infrastructure. They record conditions in any number of environments including industrial facilities, farms, and hospitals. The sensor network connects to the internet or computer networks to transfer data for analysis and use.

Sensor network nodes cooperatively sense and control the environment. They enable interaction between persons or computers and the surrounding environment.

Figure 1, illustrates the widespread use of sensors connected via multiple sensor networks.

Figure 1: Smart City - Sensors and Sensor Networks
Smart City WSN

Wired vs. Wireless Sensor Networks

Sensor networks can be wired or wireless. Wired sensor networks use ethernet cables to connect sensors. Wireless sensor networks (WSNs) use technologies such as Bluetooth, cellular, wifi or near field communication (NFC) to connect sensors.

WSNs are easier to deploy and maintain and offer better flexibility of devices. With the rapid development of sensors and wireless technologies, WSNs have become a key technology of the IoT. WSNs don't need the physical network infrastructure to be modified.

Operation of a Sensor Network

Sensor networks typically include sensor nodes, actuator nodes, gateways, and clients. Sensor nodes group inside the sensor field and form networks of different topologies. The following process describes how sensor networks operate:

  • A sensor node monitors the data collected by the sensor and transmits this to other sensor nodes.
  • During the transmission process, data may be handled by multiple nodes as it reaches a gateway node.
  • The data is then transferred to the management node.
  • The management node is managed by the user and determines the monitoring required and collects the monitored data.

Figure 2, shows the components of a sensor network.

Figure 2: Sensor network components
Sensor network components

Sensor Nodes

There are many nodes in a sensor network. These nodes are the detection stations. There is a sensor/transducer, microcontroller, transceiver, and power source:

  • A sensor senses the physical condition, and if there is any change, it generates electrical signals.
  • The signals go to the microcontroller for processing.
  • A central processor sends commands to the transceiver and data is transmitted to a computer.


The sensor is the bond of a sensor network node. Examples of sensors include temperature sensors, accelerometers, infrared detectors, proximity sensors, and motion detectors.

Figure 3, shows the sensors used in a self-driving (autonomous) car.

Figure 3: Sensors used in a self-driving car
Autonomous vehicle sensor

Sensor Network Topologies

There are four types of sensor network topologies:

  • Point to point network
  • Star network
  • Tree network
  • Mesh network

Point to point topology

In this topology, there is no central hub. A single data communication channel is used for a secure communication path. Each device can act as a client and a server in it.

Star network topology

Unlike point to point networks, a centralized communication hub is present in a star network. Each communication flows through a centralized hub.

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