For part 1, I programmed two leds to increase their brightness from off to the brightest and gradually decease to off. For part 2 and part 3, I just made the standard circuits.
For part 4, I used a photoresistor as the sensor and keep track of the lowest value and highest value it receives. The video I uploaded blurred and did not show clear display. So I wrote down the experiment results: the lowest value was 14 and the highest value was 45.
Part 1 “Pulse”:
Part 2 “Color Mixer” :
Part 3 “Pulsing Color Mixer”:
Part 4 “Finding Sensor Limits”: