Part D: Narrative design

Q7. An Unmanned Aerial Vehicle (UAV) using four wheels sensors A, B, C, and D. Every two wheels are parallel to

provide balance during landing, A//C, and B//D. Design the functional system for landing wheels. A circuit is required

to indicate the status of the landing wheels before landing. A green LED display turns on if any parallel pairs or all four

wheels are down; the switch will activate the system to prepare for landing. A red LED display turns on if all wheels,

or the two parallel wheels, fail to come down properly before landing.

Assume that its sensor produces a LOW voltage when a leg is down. When a landing wheel is stuck, its sensor has a

HIGH voltage. Implement a circuit to meet this requirement.