Interesting and alternative uses for electronics components?
Thermal cutoff for a power supply uses normal 4007 diodes as temperature sensors.
Hollow pieces of stripped wiring plastic, heated slightly and used as heat shrink.
Reverse voltage of an LED used to detect daylight and guide a solar tracking motor.
21W light bulbs used as constant current sources because of their PTC characteristics.
Fuses made from single strands of copper, doubled up to handle greater current.
There must be more.
Using components and junk in ways they weren't intended opens up all kinds of possibilities for electronics people and students on tight budgets who don't have access to components and technology.
Are there other smart ways to put the characteristics of certain parts to smart use?