Measuring the workplace using sensor technology can give numerous relevant workplace insights. Considering the purpose of using sensor technology is important for the next steps of understanding and improving the workplace. Sensor type, placement, communication, and energy resources are just a few factors to consider when installing sensor technology at your workplace. In this blog, we are interviewing Mike Kaandorp, our iBASX Senior Project manager, and discuss all the aspects to consider when using sensor technology in the workplace. Mike takes me through the office showing how we are using and testing sensor technology, and discusses various important aspects to consider. In this blog, we share a summary of this conversation, to understand workplace sensor technology with Mike.
Purpose
The first thing Mike talks about is the purpose of sensor technology. Mike explains that there are basically four purposes for using sensor technology: Desk occupancy, people counting, large space monitoring, and air quality. Desiring to know the number of people that pass through a hallway is different from knowing which desks are occupied and when. This directly affects what kind of sensors you need to use, their placement and more. We’ll take these four purposes as an outline for this blog, and discuss some other things to consider after that, hoping to give a good overview that explains Mike Kaandorp’s view on sensor technology.
| Purpose | Sensor technology | Placement | Communication | Energy resource |
| Desk use | Passive Infrared | Under the desk | LoRa | Battery powered |
| People counting | Optical or infrared or time-of-flight | Around doors/hallways | Wifi or LoRa | Battery or grid-powered |
| Large space monitoring | Radar, optical or motion | Ceiling | Wifi, LoRa or WLAN | Battery or grid-powered |
| Air quality | CO2, temperature, humidity, particulates | Wall | Wifi or LoRa | Battery or grid-powered |
Table 1. Purpose and factors of sensor technology
Sensor technology and placement
Desk occupancy
Measuring desk occupancy is relatively straightforward for us, Mike argues. This is usually done by mounting a Passive Infrared sensor under the desk. Infrared is in the wavelength spectrum that is beyond what we can see with the human eye. When a person passes by, the sensor captures a change in Infrared radiation. When the person leaves, the sensor generates a negative differential change reversely. This makes them able to detect people. Passive infrared sensors can only understand whether there are people are not, but now how many. Therefore, they are perfect for measuring desk occupancy. They are called “Passive” because they only activate when a person passes by. Therefore, they hardly use energy. So, we have them battery-powered which makes them last more than five years.
People counting
For people counting, Mike says there are multiple options. We also experiment a lot with different technologies. For example, two infrared sensors (one sender and one receiver) can be placed at each side of the door or hallway which monitor the disruption of the signal caused by people passing through. Monitoring through infrared sensors is accurate, but when people move through the beam at the same time, this can lead to inaccuracies. In big hallways, for example, this causes issues. The other options are heat, time-of-flight or optical sensors mounted above the opening. An Optical sensor is a fancy way of saying that the sensor uses image recognition and translates this information to the number of people passing. The optical sensor makes pictures, processes the images and deletes the old pictures again. Since they take a picture from the top of the head, and delete the pictures directly again, they are relatively privacy-friendly. However, if the sensor is connected to Wifi, this could make people able to hack the sensor, which causes significant issues. But we’ll come back to that. Time-of-flight (ToF) sensors are another option. These sensors emit light and calculate the time it takes to bounce back. When someone passes by, the bounce-back time changes, and thus a person can be detected. This sensor is free of any privacy problems and can be placed on the ceiling to get accurate data.
Large space occupancy
Meeting rooms and large open spaces can be monitored by multiple types of sensors. At Measuremen, we are usually using motion sensors. Depending on the size and configuration of the meeting room one or multiple meeting room sensors are mounted on the ceiling. Motion detection does not require a lot of energy, so they are battery-equipped and last over 5 years on a single charge. There are also new technologies on the market that use Radar technology and can monitor large areas with great accuracy. This also requires fewer sensors per area. Radar uses radio waves to determine the distance, angle and radial velocity of objects at a workplace. It is an active sensing device, with a source of illumination for locating people. It typically operates in the Microwave region of the electromagnetic spectrum from about 400 megahertz (MHz) to 40 gigahertz (GHz). You don’t have to worry about privacy problems when using radars, since it just sees the presence of an object and its movement. Mike is excited about this sensor. However, Mike notices, that these radar sensors come with their own challenges when it comes to power supply and communication. They need to have a power supply and they communicate through Wifi. it’s dependent on the client’s context whether this is an actual issue. And might be a topic for another blog.
Air quality
Air quality can be measured in many ways: temperature, CO2, humidity and particulate matter. When we place a sensor, we do this quite carefully according to Mike. You need to keep the HVAC, windows and door openings in mind that influence the flow of the gasses. For example, we try to place the CO2 sensor exactly at 160cm from the ground to get reliable readings across all the spaces. This required quite some testing, but we have figured it out now.
Costs, accuracy, controllability, and privacy
Next to picking the right sensor, there are also other things to consider. For a client, this is a mix of costs, accuracy, controllability, and privacy. Which are trade-offs from one another. For example, the more accuracy a client desires, the more sensors we need, the higher the costs. Using optical sensors improves accuracy but has negative effects on privacy. Controllability refers to the control that is needed to handle the sensor technology. The available power supplies and the sensor communication (through LoRa or Wi-Fi for example), are influenced by the clients’ office building and IT infrastructure.
Conclusion
In short, there are many options when it comes to picking the right sensor for measuring the workplace. But if you think well about the purpose, the right sensors will emerge. However, this blog gave just a short overview of the available sensor types and did not elaborately discuss everything involved such as the communication network, power supply, sustainability, differences in suppliers and more. Moreover, the world of sensor technology is also continuously evolving. At Measuremen, experts such as Mike, know all the details from A to Z about sensor technology and keep a good eye on all the developments in the market. With their help, your journey of picking the right sensor technology for your workplace will be a smooth ride. They are experts and know much more about the sensors, and sensor communication than is discussed in this blog. So, contact them to get things moving!
Other sources used for this article:
https://resource.milesight.com/milesight/iot/document/milesight-vs121-ai-workplace-occupancy-sensor-whitepaper-en.pdf
