I'd recommend you have a read about the "Sunbeam Radiant Toaster" first released in 1948 [0]!
> When you stick a piece of bread into this toaster, it pushes down a series of cleverly designed levers that have just enough tension to lower and raise two slices all by themselves — and it’s got a mechanical thermostat inside that stops your bread toasting when it’s toasted and ready, NOT after some arbitrary amount of time.
> When you stick a piece of bread into this toaster, it pushes down a series of cleverly designed levers that have just enough tension to lower and raise two slices all by themselves — and it’s got a mechanical thermostat inside that stops your bread toasting when it’s toasted and ready, NOT after some arbitrary amount of time.
[0]: https://www.theverge.com/22801890/sunbeam-radiant-control-to...