4.1(a): Diagram of connections between HC-SR04, LED and board | Download Scientific Diagram
Is it possible to make an LED turn on with an HC-SR04 without using an arduino? Only when an object is near it? - Electrical Engineering Stack Exchange
diymore HC-SR04P/SR04 Ultrasonic Sensor HC-SR04 Measuring Distance Sensor LED Display Module for Arduino Robot - AliExpress
Distance Measuring with LED Notifier using HC-SR04 Ultrasonic Sensor a – QuartzComponents
Led distance measurement using ultrasonic sensor and aurdino - Hackster.io