Articles from "Microelectronics News"

Fraunhofer Group for Microelectronics

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Crash sensor increases warehouse safety

Shelves in warehouses have to be able to withstand some punishment. They are frequently hit by forklift trucks when the staff have to maneuver goods through the narrow aisles quickly. For this reason, their stability needs to be checked regularly. Inspection rounds, however, take a lot of time and only provide a snapshot of the situation. Fraunhofer researchers have now developed a wireless sensor-based system that monitors the state of the shelves continuously.


Even minor collisions can destabilize the shelves’ struts over time – the worst case would be collapse of high shelving. For this reason, the struts must be checked regularly for damage. Currently, an employee inspects each shelf individually, which is laborious and time-consuming. If a strut is damaged immediately after the inspection round, the damage remains undetected for the time being. A new type of monitoring system developed jointly by researchers at the Fraunhofer Institute for Microelectronic Circuits and Systems IMS and IWS Handling GmbH offers more effective and reliable protection. A wireless sensor network can be used to monitor the state of each individual strut around the clock.

A sensor reports a collision

The struts are usually covered with a type of protective airbag to absorb the impact of a collision. “We have integrated sensors into this protective device that measure the pressure inside the airbag,” explains Frederic Meyer, project manager at Fraunhofer IMS. If an airbag is run into, the sensor registers the change in pressure and reports it via radio to a central control station. This could be in the manager’s office, for example. Repeaters installed at various locations in the warehouse forward the reports from the sensor nodes to the control station seamlessly. The manager only needs to take a look at the display on the base station to know when and where the last collision in the warehouse took place. The system also automatically shows whether the collision was minor, middling or serious.

Intelligent energy management

Energy management played a central role during development. “Using a system like this only makes sense, of course, if you don’t need to change the batteries in the sensors all the time,” explains Meyer. The Duisburg-based researchers have therefore configured the system in such a way that the electronics are usually in a low-energy standby mode. Only if a change in pressure occurs do the sensor nodes ‘wake up’ and become active. Each sensor node, however, sends a ‘life sign’ with its battery status to a repeater at regular intervals. This ensures that failure of a transmitter node does not go unnoticed. The project is being funded by the Otto von Guericke e.V. working group of industrial research associations.


Frederic Meyer
Phone +49 203 3783-193
Fraunhofer Institute for Microelectronic Circuits and Systems IMS
Finkenstrasse 61
47057 Duisburg