Much like the mechanical alarm clocks that eventually replaced them, their services weren’t always appreciated. How Knocker-Uppers WorkedNo two knocker-uppers worked the same way. In 1930s, Mary Smith earned 6 Pence per week working as a knocker-upper in East London, a job that involved waking sleeping workers by shooting dried peas at their windows. Mary Smith is said to have collected six pence per week: hardly enough to purchase a four-pound loaf of bread. The profession gradually faded away at the start of the 20th century, when mechanical alarm clocks became both available and affordable.