Know how the potentiometer works and make it control the LED
The sensor used is ultrasonic sensor; hc-sr04p, which can be operated with 3.3V supply (for NODEMCU). The code to understand the ultrasonic sensor and how it works. Using the LED as a trigger to alert the user it in presence of obstacle.
Connect the apps from the smartphone to the ESP8266. Making the project become a Internet of Things. The apps can monitor the ultrasonic sensor and also control the buzzer.