> You might think such a system would involve a thermostat, a microcontroller, and an actuator, but this design [...] has bimetallic arms with steel on the oute

> You might think such a system would involve a thermostat, a microcontroller, and an actuator, but this design [...] has bimetallic arms with steel on the outer surface and copper on the inner surface. As the filament heats up, the arms warm up, causing the copper to expand faster than the steel. This expansion pushes the arms open, releasing the lighter. The coil spring then causes the handle to pop out, signaling that the lighter is ready. Maybe I am in a picky mood, but for me the intro made it sound like all three items (thermostat, microcontroller, actuator) would not be necessary, though of course only the microprocessor is missing from the design (thermostat -> bimetallic arms, actuator -> spring). Mandatory link to another marvel in the same problem space (I found the 19min video worth the time): "An Antique Toaster That's Better Than Today’s [video]" https://www.youtube.com/watch?v=1OfxlSG6q5Y https://www.youtube.com/watch?v=1OfxlSG6q5Y https://news.ycombinator.com/item?id=21164014 https://news.ycombinator.com/item?id=21164014 [2019, 386 points|5 years ago|232 comments]