Types of smart building sensor and how they work
The world of smart building sensors can be a confusing one. There are lots of different options out there and there’s a whole lot of information too – ranging from the very basic to the impossibly technical. Here’s our break down of types of sensors found in smart buildings.
Arguably, the first thing we ever wanted to measure within a workspace, temperature is key to several factors and can be a very useful metric in almost every work environment. Here’s the HSE website with guidance for the reference.
In an industrial setting such as manufacturing, there are numerous advantages to measuring temperature. Machinery has to operate within tolerances, and if the ambient temperature in a factory or workshop doesn’t remain within these parameters, the performance or longevity of the equipment may be impacted. Even if not, operating outside of these conditions may void the warranty or lease agreement of the equipment.
Temperature measurements can contribute to predictive maintenance too. Many machines used in manufacturing and computing are sensitive to temperature and have to be protected from overheating. With smart temperature sensors, businesses can automate heating, ventilation and air conditioning controls to maintain ideal conditions and automatically detect failures or faults as they happen, or even notice trends or patterns which warn you of the failure before it happens.
There are four types of temperature sensors:
Semiconductor-based sensors: Placed on an integrated circuit, these identical diodes use temperature-sensitive voltage compared with current conditions, allowing them to record changes in temperature.
Thermocouple: As the name suggests, this consists of two wires – these are made from different metals and placed a different points, with the change in voltage between the two points showing change in temperature.
Resistance Temperature Detector: A film or wire is wrapped around a ceramic or glass core, with temperature measured from the resistance between the element with temperature. These tend to be the most accurate type of sensor, but can also be the most expensive.
Negative Temperature Coefficient Thermistor: Providing high resistance at low temperatures, as temperature increases resistance quickly drops – reflecting changes quickly and accurately.
This type of sensor will let you maintain ideal conditions and take action straight away if there’s a change. In homes and businesses they’re used to control heating, ventilating, and air conditioning systems. They’re used in manufacturing plants, hospitals, museums, greenhouses and weather stations – any environment that’s sensitive to moisture.
There are three common types of humidity sensors:
Capacitive: With a porous dielectric substance at the centre, surrounded by two electrodes, the sensor uses water vapour to monitor humidity – when the vapour reaches the electrodes it creates a voltage change.
Resistive: Less sensitive than capacitive, they operate on a similar basis, using electrical change to measure relative humidity. However, they use ions in salts to measure this change to resistance on the electrodes.
Thermal: Two matched thermal sensors conduct electricity based on humidity of the air surrounding them. One is coated in dry nitrogen, the other measures ambient air – with the difference between them measuring the humidity reading.
Electrical current monitoring sensors
Electrical current (CT) sensors measure real-time energy consumption at a circuit, zone or machine level. Knowing how much energy is being used has two main uses.
Firstly, you can identify where you use and waste the most energy, allowing you to make savings. You can also automatically switch off assets when they’re not in use. Secondly, if you can recognise normal operating conditions you can also see when machinery isn’t functioning as well as it should. For example, a higher-than-average operating current could tell you that a motor has been overloaded.
This insight means you can schedule maintenance when it’s actually needed rather than pay for routine inspections. You can also fix potential problems straight away and keep unplanned downtime to a minimum.
Types of CT sensors
Split core: These can be opened and fitted around a conductor, so are ideal for existing configurations.
Hall Effect /DC: These sensors use what’s known as the Hall Effect to measure both AC and DC current, measuring the changing voltage when a device is placed in a magnetic field. They can be be either open or closed loop. Open loop are compact, low cost and accurate, closed loop offer fast response and low temperature drift.
Rogowski coils: Flexible current transformers, these are easy to install. A thin coil threads around the conductor and is snapped closed.
Solid core: Best for new installations, these sensors are complete loops with no way of opening. They are renowned for their high levels of accuracy.
Other types of smart building sensors
While we don’t currently offer these sensor types as off-the-shelf products, we can work with you to develop bespoke solutions – read up on our design and manufacturing capabilities to find out more or use our contact form to get in touch.
Other types of sensors
Optical sensors measure electromagnetic energy including electricity and light. They’re used in industries such as healthcare, energy and communications to monitor variables including light, radiation, electric and magnetic field and temperature.
Proximity sensors, much like motion sensors, detect the presence of an object and measure how close it is. One of the most familiar uses is reverse parking sensors in cars.
Pressure sensors detect pressure and alert the system administrator of any deviation from the standard pressure range – similar to machine monitoring. This is useful in manufacturing as well as in water and heating systems.
Water-quality sensors are used in environmental management to measure chemicals, ions, organic elements, suspended solids and pH levels in water.
Smoke sensors detect levels of airborne particulates and gases. While they’ve been around for a while, the development of IoT means they’re now able to notify users of problems immediately.
Level sensors determine the level of fluids, liquids or other substances in an open or closed system. They’re mainly used to measure fuel levels, but are also used to measure sea and reservoir levels and in medical equipment, compressors and hydraulics.
Image sensors can be found in digital cameras, medical imaging and night vision equipment and biometric devices. They’re also used in the car industry and play an important role in the development of driverless cars.
Accelerometer sensors detect vibration, tilting and acceleration in an object. Uses include anti-theft devices, vehicle fleet monitoring, aircraft and aviation industries and consumer electronics, including smartphones and pedometers.
Gyroscope sensors are used together with accelerometers and measure angular velocity, defined as a measurement of speed of rotation around an axis. Their main applications include car navigation systems, game controllers, robotics and consumer electronics.
Editor’s note: This post was originally published on Mar 4 2019 and updated on Jan 24 2024.