Automatic door

[1] In the 1st century AD, mathematician Heron of Alexandria in Roman Egypt invented the first known automatic door.

After a few hours atmospheric pressure built up in a brass vessel causing it to pump water into adjacent containers.

These containers acted as weights that – through a series of ropes and pulleys – would open the temple's doors at about the time people were to arrive for prayer.

[2] In 1931, engineers Horace H. Raymond and Sheldon S. Roby of the tool and hardware manufacturer Stanley Works designed the first model of an optical device triggering the opening of an automatic door.

The invention was patented and installed in Wilcox's Pier Restaurant in West Haven, Connecticut for the benefit of waiters carrying plates of food and drink.