https://www.adafruit.com/product/263
Getting Started with Arduino By Massimo Banzi - 3rd Edition : Adafruit Industries, Unique & fun DIY...
This valuable little book offers a thorough introduction to the open-source electronics prototyping platform that's taking the design and hobbyist world by...
getting started with arduino
https://projecthub.arduino.cc/Isaac100/getting-started-with-the-hc-sr04-ultrasonic-sensor-7cabe1
Getting Started with the HC-SR04 Ultrasonic sensor | Arduino Project Hub
A basic introduction to the low cost and accurate HC-SR04!
getting started withthe hcultrasonic sensorarduino project