Wireless and battery-free radio sensors are proving increasingly beneficial as the Industrial Internet of Things matures. They can be used directly on moving parts or in hermetically sealed environments, for example to measure the flow, pressure and temperature of liquids or gases. Above all, industrial companies save themselves time-consuming and cost-intensive cabling.

However, it is of crucial importance that wireless sensors employ energy harvesting, rather than being powered by batteries. This is because replacing a single battery in an industrial environment costs between $250 to $500 US dollars. Although the actual battery exchange happens quite quickly, the travel, locating, device-testing, and documentation increase the hourly costs enormously. Very often, batteries are said to have a service life of two to five years, but in practice they are often replaced every one to two years in order to avoid early failures.

Resource saving and environmental protection are also becoming increasingly important: the prices for copper are steadily going up and the harmful components as well as safety aspects of batteries are a serious problem. A sustainable solution is needed that takes both the financial aspect and the damage to the environment into account.

There is a more sustainable way for wireless sensors: sensors that obtain their energy from movement, light, and temperature differences according to the principle of energy harvesting. This means that they neither require cables nor batteries for smooth operation. Therefore, they can be flexibly mounted directly on moving parts. The combination of radio and energy harvesting enables new applications entirely without maintenance requirements and battery waste.

Sensors in quality control

Quality monitoring is a key aspect of the production process in order to ensure that the final product meets predefined parameters. To achieve this goal, a variety of parameters must be monitored, such as environmental factors like temperature, humidity, and air quality; process factors like speed, force, pressure, and temperature; or material factors like the starting materials used.

Many of these parameters are suitable for automated monitoring with the help of sensors. Ideally, sensors can be optimally integrated into existing production processes and require neither special training nor do they cause follow-up costs in ongoing operations.

Maintenance-free process monitoring

The aim of process monitoring is to ensure that a defined production quantity is achieved, taking into account various parameters such as the required time, material and personnel. Deviations in the production process must therefore be detected at an early stage and failures avoided. The integration of wireless sensors in production offers decisive advantages: wireless sensors can be used, for example, in hermetically sealed environments such as pipelines to measure the flow, pressure, and temperature of liquids or gases.

Read more: Battery-free wireless sensors conquer the IIoT