A central component of the 'Esima' project - 'Esima' stands for "energy self-sufficient sensor technology in interaction with mobile users" - was not only the development of energy self-sufficient sensors but also the visualization, which enables the plant operator to gain a differentiated understanding of their own processes and thus makes a contribution to Industry 4.0 factories.

With the integrated concept of simple sensor installation, data acquisition, wireless transmission and visualization, energy consumption (e.g. for individual workpieces) can be derived. The sensors can be easily retrofitted to existing production systems. All relevant consumption data is recorded during the production process: for example, electrical energy consumption (current, voltage, power) or compressed air consumption (pressure, flow rate). The wireless sensor systems can also record relevant environmental parameters such as temperature, humidity and CO2 content. The measured values are then pre-processed and transmitted wirelessly to a base station.

The measurement data obtained is visualized using an internet application developed in the project and can be viewed using mobile devices such as smartphones and tablet PCs. The presentation of the data can be customized depending on the user. For example, a machine operator can view current sensor readings and system statuses, whereas a team leader is more interested in energy consumption and production statistics.

"The results of 'Esima' show ways in which energy data can be recorded much more cost-effectively and flexibly," explains Bernd Kärcher, project manager of 'Esima' at Festo. "In the context of Industry 4.0, data acquisition, its transmission by radio and the visualization of the data in a web application on mobile devices enable efficient energy management."

In addition to the possibility of optimized energy use, users also benefit in the area of maintenance: as the sensors automatically report even the smallest deviations from the normal value, repairs can be carried out before production downtimes occur.

The joint project was funded by the Federal Ministry of Education and Research (BMBF) as part of the ICT 2020 research program in the field of "Energy self-sufficient mobility - reliable energy self-sufficient systems for mobile people".

In addition to Festo, which developed a compressed air sensor in the project that simultaneously measures pressure and flow and transmits the data obtained by radio to a base station, the following project partners from industry and science were also involved:

• Varta Microbattery supplied the necessary components for storing the electrical energy in the wireless sensors.

• Hahn-Schickard-Gesellschaft developed sensors for recording electrical energy consumption (e-meters) and environmental sensors.

• The company EnOcean contributed its know-how in the field of energy conversion and low-power radio systems to the project.

• The required wireless components and the base station were developed at the Chair of Electrical Measurement Technology (EMT) at Helmut Schmidt University.

• C4C Engineering developed and programmed the web application for visualizing and evaluating the measurement data.
• The Institute for Machine Tools and Production Engineering (IWF) at the TU Braunschweig developed methods for automated data analysis and was the test field for the prototype implementation.

In the next step, the 'Esima' system will be tested in a real production environment at the Mercedes-Benz plant in Mannheim.