Sensing and influencing the physical world

Sensors & Actuators

Sensors sense the physical world. Actuators influence the physical world. 


Together, sensors give a comprehensive 'big-data' information for analytics, decisions and presentation. The sensor suite of the system determines how intelligent a system can become, i.e. how precise and accurate analysis can be done, how valuable the information can be, and how precise automated decisions can become.

Free2move’s wireless sensors are easy to install and have a very long battery life. They are based on a common hardware architecture and wireless protocol as part of the 2Connect™ platform. There are indoor and outdoor models.

For wireless sensors, the indoor sensors make use of the SHF radio band by default. For outdoor, very long range, requirements, the UHF and VHF bands may also be used.  They are certified according to CE/ETSI and FCC, and are produced according to RoHS and REACH standards.


Actuators are devices or subsystems by which 2Connect influences the physical environment. It is through actuators that decisions are effected. Free2move's actuators share the common hardware platform with Free2move's sensors, but have richer I/O options. They are physically designed to be installed in DIN-racks, 19" racks or embedded. In addition, Free2move frequently integrates actuation through 3rd party systems, via protocols such as Modbus and KNX.


Below, the most important sensor and actuator types of 2Connect™ are described. Not every sensor or actuator type is in every installation. Each installation of 2Connect™ is fitted with the sensor and actuator types needed for the intended analytics, decision and presentation tasks given, which in turn is determined by the data model derived while orchestrating the system.

Temperature sensors

The most common sensors are the temperature sensors. Depending on what type of temperature information is required, they measure temperature differently. Ambient temperature sensors are used to monitor room temperature, and sometimes outdoor temperature. The differential between ambient sensors in adjacent spaces provides important information on how temperature fluctuations in two or more spaces are linked to each other. Temporal temperature information give important information about how temperature variations in a building correlate with each other. This is used to save energy and detect anomalies.

The contact temperature sensors can be of proximity sensor type, contact type or probe type. These are for instance used to measure engine temperature, which gives valuable information about the health of the engine, or to measure pipe temperature, to obtain information about heat loss in a heating system.

In food production; food supply chain; (e.g. cold-chain); semiconductor production; and in pharmaceutical supply chain, control of temperature is often critical for quality and health. In public spaces, such as schools, sports stadiums, shops, transportation facilities etc, temperature is important for productivity and health.

Temperature sensors are often used to calibrate other sensors, whose method of measurement has a temperature dependency.

The 2Connect™ platform encompasses a variety of temperature sensors which are selected according to the use case at hand.


Humidity sensors
For compelling reasons humidity sensors (aka moisture sensors) are increasingly demanded. As with temperature, they are critical for human comfort, productivity, fungus prevention and allergy prevention. For this reason they are important sensors in HVAC systems and public spaces, as well as homes.
A safe human comfort zone is typically within the 30 - 48 RH% and 23.0 – 23.5°C limits, but may vary somewhat due to season and the activity within the building.
In both facility management and the manufacturing industry, humidity sensors are used to detect water leakages and control other quality issues. They are used to control environment in critical manufacturing, e.g. food, pharmaceutical, semi-conductor, and in the warehousing of humidity sensitive goods, as well as supply chain.

A log of temperature and humidity variations is used to predict the dew point. This is used to prevent electric shortcuts, wood-rot, fungus, bacteria and corrosion.
Apart from the above, Free2move’s humidity sensors have been installed in sports halls, museums, and in ice-cream and chocolate production plants.
Humidity sensors have a temperature sensor built-in for calibration purposes. Therefore, for every humidity sensor, there is always a temperature sensor.
The 2Connect™ platform includes high accuracy humidity sensors which are selected according to the use case at hand.


Vibration sensors and accelerometers

Vibration sensors are used for a variety of purposes in buildings, manufacturing and transportation. One important area is the monitoring of equipment health, for instance HVAC fan motors, pumps, etc. Anomalies in vibrations are used to predict failures and calculate efficiency together with other sensors. Vibration sensors can also be used to detect anomalies in pipe systems, to monitor workplace health, e.g. prevent vibration related workplace injuries, and for security purposes.

Vibration sensors have typically 1-, 2- or 3-axes, whereas accelerometers have 3-, 6- or 9-axes. The latter are used to track objects or to perform advanced movement pattern recognition, e.g. fall detection.

The 2Connect™ platform includes high accuracy vibration sensors and accelerometers which are selected according to the use case at hand.


Gas sensor - Carbon-dioxide, CO2

Along with temperature and humidity, COconcentration is an important factor in air quality. High CO2 concentrations in buildings are usually a result of poor ventilation and are associated with occupant health, comfort and performance degradation. Long exposures at upper limits, 5000 ppm (0.5%), leads to headaches, lethargy, mental slowness, emotional irritation, and sleep disruption. Fresh air should have a concentration around 400 ppm (0.04%).

Apart from a product of cellular respiration in organisms, the gas is often used as a refrigerant, as a greenhouse gas to increase plant growth and reduce pest damage, and as a pneumatic propellant and inert gas.

Monitoring CO2 in the context of HVAC control is important in school auditoriums and lecture halls, in sports halls, officers and public areas. In normally ventilated areas, the gas mixes well in the air, but since it is also heavier than air, if there is no ventilation for a long time, it tend to concentrate along the floor and in spaces beneath the floor.

The 2Connect™ platform includes high accuracy CO2 sensors which are selected according to the use case at hand, and are calibrated from other sensors.


Gas sensor - VOC

Volatile organic compounds (VOCs) are organic chemicals that have a high vapour pressure at ordinary room temperatures. Their high vapour pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and enter the surrounding air, a trait known as volatility. For example, formaldehyde, which evaporates from paint, has a boiling point of only –19 °C (–2 °F).
VOCs are numerous, varied, and ubiquitous. They include both human-made and naturally occurring chemical compounds. Most scents or odours are of VOCs. Some VOCs are dangerous to human health or cause harm to the environment. Anthropogenic VOCs are regulated by law, especially indoors, where concentrations are the highest. Harmful VOCs typically are not acutely toxic, but have compounding long-term health effects.

The 2Connect™ platform includes high accuracy VOC sensors which are selected according to the use case at hand, and are calibrated from other sensors.


Gas sensor - Carbon-monoxide, CO

Carbon monoxide (CO) poisoning is the most common type of fatal air poisoning in many countries. Carbon monoxide is colourless, odourless, and tasteless, but highly toxic. It combines with hemoglobin to produce carboxyhemoglobin, which usurps the space in hemoglobin that normally carries oxygen, but is ineffective for delivering oxygen to bodily tissues. Concentrations as low as 667 ppm may cause up to 50% of the body's hemoglobin to convert to carboxyhemoglobin. A level of 50% carboxyhemoglobin may result in seizure, coma, and fatality. Within short time scales, carbon monoxide absorption is cumulative, since the half-life is about 5 hours in fresh air.

This requires CO sensors to have fast detection and have high alarm priority in the system.

In homes, fresh air has around 1 - 5 PPM concentration of CO, but it may increase to 15 PPM around stoves and in vehicle garages, parkings etc. The lowest level of CO alert should be 35 PPM, which is the recommended maximum level.

The 2Connect™ platform includes fast and reliable CO sensors which are selected according to the use case at hand.


Tachometers, rotation sensors & revolution counters

These sensors measure the rotating speed of a shaft, disc or wheel. They utilise different sensing principles based on the object and application. They can be magnetic, optical, infrared, mechanical or accelerometric. They are used to sense and control angular speed, often measured in Revolutions Per Minute (RPM).
Combining the measured RPM value with vibration, temperature, current consumption and air-flow of a fan engine is used to obtain a health record of the engine, and hence the need for maintenance.

The 2Connect™ platform includes fast and reliable techometers which are selected according to the use case at hand.


Pressure sensors

Differential pressure sensors give valuable information about air flow between two spaces. This is used in the monitoring of HVAC system performance and how heat flows through the building.

Barometric pressure sensors give information about absolute pressure. This is important for spaces which need to have controlled pressure, e.g. certain production processes and hospital operating theatres. Barometric pressure is also used in weather stations.

Apart from the above, pressure information is also used to calibrate other sensors, e.g. gas sensors of various types.

The 2Connect™ platform includes high accuracy pressure sensors which are selected according to the use case at hand.


Operation theatre

When right climate is really critical

Facility management

When cost and service level are really important