The surprising reason this German island is testing Li-Fi

The island of Mainau has become home to Germany’s first real-world application of Li-Fi

THE small island of Mainau in Lake Constance, with its beautiful botanical gardens and baroque palace, is not the first place you’d expect to find a cutting-edge lighting experiment.

But this local tourist spot has become home to Germany’s first real-world application of Li-Fi – and one of only a handful in the world.

Superfast data through light: a laptop hooked up to a Li-Fi receiver in the pilot project on Mainau

Li-Fi is a faster, more reliable alternative to Wi-Fi that transmits data through visible light instead of radio waves. But the trial on Mainau was motivated not by a desire for faster downloads, but by concerns about what Wi-Fi could be doing to people’s health.

The idea came from the Lake Constance Wireless Initiative, a local group that wants to cut down on the so-called ‘electrosmog’ of radiation from Wi-Fi, mobile phones and other devices, which they believe carries health risks.

Their concerns struck a chord with Countess Bettina Bernadotte, who leads the organisation that manages the island, and says her support for the research comes from ‘personal conviction’.

LED luminaires in the room were equipped with special modulators that encode data into the light they emit. The system was installed gradually in phases, to give researchers the chance to assess the benefits of different set ups.

The trial was run with help from the Fraunhofer Heinrich Hertz Institute (Fraunhofer HHI) and funding from the regional environment ministry.

It has now been going continuously for a year with no faults and ‘highly positive’ user feedback, according to project manager Dr Anagnostis Paraskevopoulos of Fraunhofer HHI. ‘The constructive comments are already being implemented into the further development of our systems today,’ Paraskevopoulos said.

Li-Fi takes advantage of the fact that all LED lights flicker at a speed too fast for humans to see, but that can be picked up by an optical receiver. By changing the pattern of the flicker, data can be encoded into the light and transmitted at speeds in excess of one gigabit per second.

Dr Andrea Leute of the Lake Constance Wireless Initiative says a new approach to mobile communication is ‘urgently required’ to keep radiation exposure in check, and that innovations such as Li-Fi that ‘minimise the radiation load’ are important.

The effect of wireless communications on health is a controversial topic. The World Health Organisation says there is no evidence of adverse health effects from exposure to devices operating within recommended limits.

Some people have reported a range of symptoms when around Wi-Fi networks and mobile phones, and while their distress is clearly real, most scientists are doubtful that radiation from wireless devices is the true cause.

But for the island of Mainau, which promotes itself as an oasis of nature and a paragon of good environmental practice, these concerns were enough to take steps to minimise exposure.

‘This is a groundbreaking pilot project for mobile data communication without the use of radio technology, and a starting point for establishing a new basic technology that can be used where radio technology is not appropriate for health or technical reasons,’ said Dr Andrea Leute.

Countess Bernadotte told Lux: ‘We as the Island of Mainau are pleased that we were able to make a contribution to the further testing of the new technology, and we look forward to its subsequent development.’


  • A special Li-Fi zone featuring innovative developers of the technology will be part of the LuxLive 2017 exhibition and conference in London on Wednesday 15 November and Thursday 16 November 2017. Entry is free if you pre-register at


Picture copyright Calflier Photography 2017. Taken from a Zeppelin NT Airship at 1,000 feet