EM-09 · Chapter 8 · Low-Speed Interfaces & Embedded Hardware
Elevator-door state machine
Design the state machine for an elevator door with open and close buttons, an obstruction (light-curtain) sensor, a fire-service override and a power-failure mode.
| Level | ●● onsite technical |
| Track | Embedded & wearables |
| Really testing | State-machine design and edge cases. |
Full worked answer: in the book, page 218 — what to say first, how to explain it, the numbers worth quoting and the follow-ups. About the book →
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Extra explanation that is not in the book: worked numbers, where people go wrong, and how to say it in the room.
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