I briefly discussed my experience with the Mindstorms ultrasonic sensors tonight. Below is a plot of sensor data from the ultrasonic sensor mounted on a rotating pedestal (very similar to the setup on the front of the Elegoo robot kits); a 16 oz soup can (~3 in diameter) was placed about 18" in front of the sensor. No other objects were within, so the points see on the right side at 100 inches (max distance) are expected. Everything on the left is ... confusing. I'm fairly certain the sensor was detecting the floor, but it's really the sensor readings of the can itself that were most concerning to me. The can looks HUGE to the sensor. From my research, the sensors are also known to interfere with one another.
This doesn't rule out their use, but it requires consideration / compensation elsewhere in the design.
A warning about ultrasonic sensors:
I briefly discussed my experience with the Mindstorms ultrasonic sensors tonight. Below is a plot of sensor data from the ultrasonic sensor mounted on a rotating pedestal (very similar to the setup on the front of the Elegoo robot kits); a 16 oz soup can (~3 in diameter) was placed about 18" in front of the sensor. No other objects were within, so the points see on the right side at 100 inches (max distance) are expected. Everything on the left is ... confusing. I'm fairly certain the sensor was detecting the floor, but it's really the sensor readings of the can itself that were most concerning to me. The can looks HUGE to the sensor. From my research, the sensors are also known to interfere with one another.
This doesn't rule out their use, but it requires consideration / compensation elsewhere in the design.