User Manual
29
Ultrasonic Obstacle Avoidance
How the Obstacle Avoidance Works
The ultrasonic obstacle avoidance module detects and transfers the collected data to
Raspberry Pi that can calculate the distance from the obstacle. The Pi will send a command
to adjust the front wheels and rear wheels direction and rotation to control the PiCar-S walk
away from the obstacle if there is one.
Principle
Supply a short 10μS pulse to the SIG to start the ranging, and then the module will send out an
8 cycle burst of ultrasound at 25 kHz and raise its echo back to SIG. The echo is a distance
object that is pulse width and the range in proportion. You can calculate the through
the between sending trigger signal and receiving echo signal.
Formula:
Or:
Or:
We suggest to use over 60ms measurement cycle, so as to prevent trigger signal to the echo.
Procedures
Step 1. Assembly
Connect the ultrasonic module and the ultrasonic module connector to the ultrasonic module
support with M3*10 screws and M3 nuts. Reminder: It would be easier to place the nuts into
the slots with your fingers to hold underneath. Then assemble them to the Upper Plate with
M3*10 screws and M3 nuts.