Functions: An ultrasonic range finder sensor enables a robot to detect obstacles in its path by utilizing the propagation of high-frequency sound waves. The sensor emits a 40kHz sound wave, which bounces off a reflective surface and returns to the sensor. Then, using the amount of time it takes for the wave to return to the sensor, the distance to the object can be computed.
Benefits: Unlike the bumper switch and limit switch that alert you when they have been hit, the ultrasonic range finder sensor can alert you to an obstacle in the path of the robot prior to hitting it. This can allow you time to safely navigate around obstacles.
Application: The sensor can be used to determine distances to objects. It can be used as a tool to determine if any objects are in the robot’s path at all. To increase the sensing range, the sensor can be mounted to a servo to allow it to rotate.
The sensitivity of the sensor depends on the objects’ surfaces that are detected by the emitted sound waves. For example, a reflective surface may produce a different reading than a non-reflective surface. The resolution of the sensor also depends on the sound waves. However, sound waves can reflect or be absorbed and possibly not return with enough power.
- Sensitivity: Detect a 3cm diameter pole at greater than 2m.
- Usable Range: 3.0 centimeters - 3.0 meter / 1.5 inches - 115 inches
- Frequency: 40 KHz
- Resolution: 1 inch
Programming with Sensors in ROBOTC (Teaching ROBOTC for VEX)
ROBOTC Sample Code
easyC Sample Code
CAD File (STEP)
- Compatible with all VEX Microcontrollers and 3-Wire Extension Cables
- Inputs: Start signal to the ultrasonic sensor. Connect to a interrupt port.
- Outputs: 3-Wire Cable Connects to a interrupt port. Echo response from the ultrasonic sensor. Black: Ground Red: +5V Orange/Yellow: Control Signal