Recommended · for beginners
Ultrasonic Sensor with the Raspberry Pi
Why people recommend it
A guide to reading an ultrasonic distance sensor from a Raspberry Pi, including a resistor divider to drop the 5V echo signal for the GPIO pins.
Watch for: Readings can drift; check wiring and timing if results vary
In their words
I setup ultrasonic sensor on B+, following instructions given in this video.
Lynob on raspberrypi.stackexchange.com, Mar 2015. CC BY-SA.