Measuremen blog - what makes a good workplace sensor_3

What makes a good workplace sensor?

With the increasing prevalence of small, interconnected devices, the word “sensor” is used more and more in our daily lives. From a motion-activated outdoor light to a self-driving car, the way in which sensors are used to interact with the world around us have a large impact on our personal routine. This same concept can be applied to the workplace, boosting employee comfort and satisfaction, while simultaneously automating repetitive tasks and managing the available space more efficiently.

Sensor

A device which detects or measures a physical property and records, indicates, or otherwise responds to it.

Oxford English Dictionary

While the term “sensor” has a simple definition, there is a large variety of different sensor types, each capable of measuring different aspects of its environment. Of the many things that sensors do, people take most of them for granted. However, your time savings and effectiveness has been a rather intense and long process for a small group: the sensor designer. The challenge of the sensor designer is to target a specific metric that must be captured, and combine the available sensor technologies to read this, while eliminating any outside interference. Many other concerns must also be addressed, such as privacy concerns, how the sensor must be installed, and the method of transmitting the information to a central point for analysis.

 

The Pillars of a Good Sensor

The end result is a selection of devices, each representing a specific goal. In our case, a variety capable of accurately describing whether a person occupies a workspace, or a meeting room, and providing results at a frequency much higher than can be realistically achieved with human observation. The rest of this whitepaper will focus on the areas that are essential to a good sensor, and should always be considered when considering a sensor based solution.

Accuracy

With sensors being left unattended, there are no people to ensure that sensors are functioning optimally, without issues. There are two main factors that contribute to an accurate, functioning sensor:

  • Technology. Each sensor must be thoroughly tested to ensure they meet strict accuracy requirements. We aim for a sensor to capture occupancy with a minimum of 98% accuracy over a 24 hour period. There are multiple factors to consider to reach this number:
    • By measuring more frequently, we can track individuals entering or leaving a space at a higher granularity. We collect data from every sensor every 5-6 minute, giving much more insight into when a space is in use, while still maintaining 2 years of battery life.
    • Filtering is a necessity – to not just track motion, but also if that motion is by a human. We do this by only measuring infrared radiation, so as not to catch chairs moving around, for example.
    • Each sensor is specialised to its role. Each device has two or more different sensor types, to combine data and produce one verified reading. Our desk sensors detect movement of one’s legs, and body heat of the abdomen, for example. With both, it is impossible for a person standing nearby to trigger the sensor accidentally.

 

  • Placement. A sensor will only work as intended when it is correctly installed; if the sensor is not placed optimally, it could be measuring people outside the space too. It is often difficult to detect this after the fact, so extra care must be taken by the sensor installation team, with stringent training requirements.
    • Is the sensor measuring the right area? Too small, and activity around the edges will be missed. Too big, and activity from outside the room or space could be mistakenly interpreted as occupancy.
    • Is there anything in the way of the sensor? It’s quite common for a desk to have a central metal beam, which could block the sensor from looking towards the person.
    • Are there any objects that could accidentally trigger the sensor? A sensor does not look for a person, it looks for a combination of conditions that indicate a person. An object such as a heater with a moving vent could affect results.
    • Poor signal strength could result in missing results, lowering accuracy. Elevator shafts, concrete walls and microwaves all play a part in this, and awareness of the environment the sensor is being installed in is key.

 

Frequency

Measuremen’s experience has found that observations through Workplace Occupancy Studies can be accurately conducted once per hour, while a sensor can collect data at a much higher frequency; our current sensors are able to read its environment every 5 minutes or less, providing 12x more data points throughout a regular working day.

A sensor presents a new method of collecting data, but no method is without its advantages and disadvantages. A sensor is specifically tuned to measure one metric, and measure it at a precise interval; a human observer, on the other hand, can collect a larger variety of data at a slower pace. Both approaches complement each other; a person can gain a more in-depth understanding of the situation, and adapt to changing circumstances more quickly, such as a desk or chair being moved. A sensor provides a very rigid, reproducible type of data, without the natural variances that can happen from person to person. In this context, sensors provide accuracy and reliability that people can never match.

Reliability

A major benefit of using unobtrusive sensor technologies is its “hands-off” nature. Once the sensor is installed and confirmed to be functioning correctly by a trained installer, the device will function for years with almost no human intervention. Data is collected constantly on a 24/7 basis, so a compromise must be struck; how do you keep at the forefront of technology, without the reliability pitfalls that come with it?

With such a fast-moving field, it’s important to spend time to take the edge off the bleeding edge, and produce a solution that is reliable and robust.

The road to the ultimate sensor, Elvin Luff

This balance is maintained by marrying components widely in use today with unique new concepts, tailored to a new field. Reinventing the wheel is exciting, but comes with risks not suited to a working enterprise environment. With this in mind, Measuremen set out to use as many widely available technologies as possible, to create a solid foundation for our new ideas. We demonstrate these ideas in our Innovation Lab, where we actively test new sensor technologies in our office spaces. This gives us a real, living environment that pushes our sensors to the limits. Only once a sensor has passed months of testing do we offer the technology to our clients.

A core technology in the sensors is LoRaWAN, the wireless communication method used for sending data to the cloud. This is a proven protocol, with its security verified by experts and a strong backing, including telecommunications companies such as KPN and Orange. Using this as a building block has allowed us to build new sensors, with confidence that our data will always be received.

 

Longevity

Purely from a cost perspective, replacing devices with newer technologies frequently does not provide good returns on investment, compared to the gains in functionality received. Installing (and removing) sensors takes time, and a level of trust is built in the accuracy of data gathered from these devices over their lifespan.

When a device meets all other pillars of a Good Sensor, the next step is to ensure that it stays this way. Ultra-low power consumption devices like the Measuremen sensors can continue to function for up to 7 years without the need for battery replacement, ensuring that little to no technician intervention is required for the whole service life of the device.

Another factor is how long a sensor stays secure. New vulnerabilities are uncovered every day; while it is impossible to guarantee a device’s future security, we can take every step to minimise the possibility of data breach today. Simplicity is key – by only providing enough software for the sensor to do its job, and not connecting it directly to the internet, we reduce the possibilities of attack.

 

The Measuremen Sensor

Motion sensors have been in our daily lives for years already, but the technology behind them is more advanced than you might think. The specific type of motion sensor we have developed only detects infrared light.

What this means is that the sensor will only record when a heat emitting object walks past it, such as a person, while ignoring all other outside factors. This method of filtering allows us to accurately determine if someone has entered a space, without the need for cameras. Not only are cameras more expensive, but they raise many privacy concerns among employees.

Why are these details important? By examining the small details in sensor technologies, one gains a true understanding of how we achieve a Good Sensor. These details allow us to bring the cost of each sensor down far enough to become cost effective to place a sensor under every desk.

Looking Forward

Working with this criteria for a Good Sensor, Measuremen is developing a portfolio of sensors for a variety of different workplace situations. From measuring space utilisation, to air quality levels, the Measuremen Innovation Lab already has a variety of different models in testing phases to accurately deliver insights, from small shared offices to large multi-level office buildings.

The possibilities for using sensors extends beyond the data they can gather. Using these technologies, we can gather data for longer periods of time for little extra cost, and theoretically collect data for years. This allows for employers to not only gain insights into how their workspaces are being used today, but also to see how their workspace changes over time. This data is available on demand and can provide instant feedback into how changes in the environment change behaviour throughout a space.

What will these insights show us? Only time will tell, and Measuremen has multiple sensor projects planned over the course of 2019. By ensuring that our sensor technologies perform optimally from the get-go, we look forward – how will your workspace look in 2 years time? A Good Sensor will be reliable, ready, and able to show you at a moment’s notice.