Science Buddies: "Ask an Expert"

I have replaced the HC-SR04 ultrasonic distance sensor with the Parallax Ping ultrasonic distance sensor for the Build Obstacle-Detecting Glasses for Visually Impaired People project. Could you please let me know the changes for the code. I have tried to use digital pin 7 for SIG and GND for GND and 5V for 5V but the sensor just keeps flashing a light at a very high frequency. I have used the PING example code and it still doesn't work. Thank You.

Hi unsajatoi,

Your wiring sounds correct! The Parallax PING sensor uses only one pin (SIG), while the HC-SR04 uses two pins (TRIG and ECHO). The flashing light might actually be a good sign because it means the sensor is trying to measure distance. First, try running the PING example code and opening the Serial Monitor at 9600 baud. Move your hand closer to and farther away from the sensor. Do the numbers change? If they do, the sensor is probably working. You will just need to change the original code so it uses one pin instead of two. If the numbers don't change, check that all the wires are connected correctly. Could you tell us what numbers you see in the Serial Monitor? This would help us figure out what is wrong. Good luck!