45
v.
Servo Controller
The Servo Controller is built based on PCA9685. PCA9685 is a 16-channel LED
controller with I2C bus interface. The resolution ratio of each channel is 12 bits
(2
12
=4096 levels). The controller works in a frequency between 40Hz and 1000Hz
and its duty cycle can be adjusted in a range of 0 to 100%. It provides PWM signals
for the servo and controls the rotation angle of the servo. Meanwhile, the module
controls the duty cycle of the square waves output from channel 14 and 15 to
regulate the rotational speed of the DC motor, so as to control the speed of the car.
vi.
USB Wi-Fi Adaptor
The adapter helps Raspberry Pi connect to a Wi-Fi hot spot.