This problem concerns wind measurements made by the wireless weather station. The wind-speed measurement uses a rotating anemometer connected by a shaft to an enclosed disk that is one-half clear and one-half black. There is a light above and a photodiode below the disk in the enclosure. The photodiode produces a 3 V signal when exposed to light and a 0 V signal when not exposed to light.

(a) Sketch the relative appearance of voltage waveforms produced by this sensor

(1) When the wind is calm.

(2) When the wind is 10 mph.

(3) When the wind is 100 mph.

(b) Explain verbally what information the microcomputer must have available and the tasks it must perform to convert the voltage waveforms produced into a binary number representing wind speed in miles per hour.