Some readers may remember a somewhat strange project presented in Elektor last century which consisted of a special set of spectacles, allowing several members of a family gathered together in front of a single TV set to simultaneously watch different programs. The glass of these glasses was made with a curtain of horizontal blinds which opened and closed at a given frequency in precise synchronisation with the frequency of multiplexing of the programs on the screen. It was necessary to choose the right frequency to only view frames of the desired program. For sound, headphones were used.

This preposterous idea resembles that of the "Les Lunettes" night driving glasses by Valeo. Here the frequency of the liquid crystal “shutter” of the glasses is synchronised with the frequency of the LED headlights of the vehicle, for optimal vision. The same operation has the opposite effect on the headlights of any vehicles coming toward you – their brightness is attenuated sufficiently to avoid excessive glare. According to the manufacturer, wearing these glasses has no effect on the displays in the car, or on a Heads-up-display (HUD)

As for the battery autonomy, we’ll talk of that later.