In Britain and Ireland, a large number of enterprising early birds made a living waking people for work.
A knocker-up would be paid a few pence a week to make the rounds and rouse workers, banging on their doors with a short stick or rapping on upper windows with a long pole. The knocker-up would not move on until he received confirmation that his drowsy client was up and moving.
The profession died out in the 1920s as alarm clocks became cheaper and more reliable, but a few specialized knockers-up — such as Doris Weigand, employed by a railway depot to summon workers for short-notice shifts — survived for a few decades more.
Here is the full story, via Michael Clemens. Remember how the Brits used to say “can you knock me up in the morning?” Here is the Guardian on the race to build the world’s first sex robot.