FREIBURG/INNSBRUCK, 10th November 2015. Temperature, moisture and air pressure need to be precisely measured in museums, libraries and archives. This needs to be more cost-effective and maintenance-free in the future. Freiburg researchers have now developed the world’s first battery-free internet sensor. Using a special solar cell, it receives power indoors and sends the measured values of several tens of thousands of linked mini sensors direct to the internet via WiFi or GSM. A base station is no longer needed. Once on the internet, the data can be documented and alarm notifications can be automatically sent to the person in charge by email or SMS. At the Exponatec in Cologne from 18th to 20th November 2015, Dr. Tolgay Ungan’s research group will present the endiio GmbH sensor for the first time in hall 3.2 at stand D.065. The newly founded endiio GmbH is a spin-off

Tens of thousands of mini sensors are only woken up when needed

The internet sensor uses a patented wake <up radio technology, which allows tens of thousands of mini sensors to be “woken up” from deep sleep on demand, so that the measured data can be collected. This makes the system 10,000 times more economical than conventional radio solutions. Both the internet sensor and the mini sensors are supplied with energy via indoor solar cells and can also be operated in low light conditions. They require at least 50 lux. When there is less than 50 lux, an integrated energy buffer with an operating lifespan of several decades can be utilised.

Simplicity meets economy

This eliminates additional costs for base stations and battery changes. Another new feature is the use of special coatings on the solar cells, which allow the components to be colour-matched to the exhibition rooms. The monitoring system uses the newest generation of

multisensors from Bosch Sensortec GmbH, which do not have to be recalibrated. This results in new possibilities for cost-effective and maintenance-free monitoring of the climatic conditions in museums. Even the flow of visitors could be identified with the help of gas sensors.

Practical development

“We have intensively discussed the practical requirements for the sensor with the Deutsches Museum”, says Tolgay Ungan. Expert requirements have already been incorporated into the development. At the Institute for Microsystem Technology at the University of Freiburg, so-called energy harvesting technologies have been researched for a long time, with the aim of being able to operate microsystems in an energy self-sufficient and therefore battery-free manner. They would use energy from the environment, record sensor values and send these wirelessly. Until now, these microsystems were able to obtain their energy from mechanical movement, temperature difference (Peltier effect), light (solar cells) or even blood glucose (fuel cells), but were only able to transmit a radio signal to a permanently accessible base station after collecting energy for a long time.

About endiio

endiio GmbH is a spin-off endiio GmbH