of (some) relevance: https://purelifi.com/ https://purelifi.com/ https://hackaday.com/2019/12/17/modulated-pilot-lights-anchor-ar-to-real-world/ https://hacka

of (some) relevance: https://purelifi.com/ https://purelifi.com/ https://hackaday.com/2019/12/17/modulated-pilot-lights-anchor-ar-to-real-world/ https://hackaday.com/2019/12/17/modulated-pilot-lights-ancho... https://hackaday.com/2019/12/22/optical-communication-using-leds-alone/ https://hackaday.com/2019/12/22/optical-communication-using-... https://hackaday.com/2005/06/13/ronja-optical-data-link/ https://hackaday.com/2005/06/13/ronja-optical-data-link/