Sensors and transducers are essential components in modern IoT applications. A transducer is a device that detects a physical phenomenon and converts it into a signal that can be measured or analysed. A sensor is a broader term covering transducers and other devices that collect information from their environment.

IoT and Sensors

The Internet of Things (IoT) connects devices and sensors to the internet, enabling data exchange and remote control. Sensors are the key components of IoT systems — they collect real-time data from their environment and transmit it for analysis in a wide range of applications, from industrial automation to healthcare.

Air Quality Sensors

Air quality sensors are essential for maintaining healthy indoor air. The most common types include:

  • CO2 meters: Measure the concentration of carbon dioxide in the air. High CO2 levels can cause fatigue, headaches, and reduced concentration. Critical in schools, offices, and other high-occupancy spaces.
  • VOC sensors: Detect volatile organic compounds (VOC) that may come from paints, cleaning products, and building materials.
  • TVOC sensors: Measure total VOC concentration, giving an overall picture of air quality.
  • Dust sensors: Measure the amount of airborne dust particles.
  • PM2.5 and PM10 sensors: Measure fine and coarse particulate concentrations. These particles can penetrate deep into the lungs and cause health problems.

Humidity Sensors

Humidity sensors measure the moisture content of air and are critical in buildings, industry, and HVAC systems:

  • Relative humidity sensors: Measure the relative humidity of air. Managing humidity is important in buildings — too high or too low moisture can cause problems such as mould growth or material drying.
  • Dew point sensors: Measure the dew point — the temperature at which water vapour begins to condense. Critical in industrial processes.

Humidity sensors are especially important on construction sites, where moisture management is essential for structural durability and indoor air quality.

Temperature Sensors

Temperature sensors are widely used in industry, home appliances, and environmental monitoring:

  • PT100 sensors: A resistance temperature sensor based on the electrical resistance of platinum. Provides highly accurate temperature measurements for industry and laboratory applications.
  • Thermocouples and semiconductor sensors: Widely used in household appliances (refrigerators, ovens) and environmental temperature monitoring.

Barometric Pressure Sensors

Barometric pressure sensors measure changes in air pressure and are important in weather forecasting, altitude measurement, and aviation:

  • Absolute pressure sensors: Measure air pressure directly in real time. Used in weather stations and aircraft.
  • Differential pressure sensors: Measure the difference between two pressures. Useful in HVAC systems and filter monitoring.

Motion and Distance Sensors

Motion and distance sensors are used for liquid level monitoring, vehicle collision avoidance, and robotics:

  • Accelerometers: Measure acceleration and motion in three dimensions. Used in collision avoidance systems and motion detection.
  • Distance sensors: Measure the distance to a target. Used in robotics, automation, and liquid level monitoring.

Electrical Current Sensors

Electrical current sensors are central to industry, energy management, and buildings:

  • Shunt resistor sensors: Measure current by detecting the voltage change across a known resistance. Accurate and reliable.
  • Hall-effect sensors: Use the Hall effect to measure current via magnetic field changes. Widely used in electric motors.
  • Current transformers: Scale current down to a safe measurement level. Used in high-voltage systems.
  • Optical sensors: Use light changes to measure current. Useful in medical devices and high-voltage applications.

Electrical current sensors are essential for energy management — they help monitor and optimise electricity consumption.