AZDelivery 3 x Compatible with HC-SR04 Ultrasonic Rangefinder Sensor Module compatible with Arduino and Raspberry Pi including E-Book!

AZDelivery is my go to for small smart electronics projects and these sensors were no different. Cheap and seems accurate in most situations. In close quarters though it does get a bit choppy, however is good enough to detect the level of salt in my water softener.

Good bargain for these five sensors, great for robot like project fast delivery,

These Ultrasonic distance sensors works fine. Easy to operate using the Adafruit libraries in CircuitPython. They give an approximate range, but don't expect anything too accurate. The distance measured depends on the shape of the object the sound is bouncing off. Angles and curves will change the measurement.But if you are wanting to know is something is in the way, or if an object has gone past the sensor, these will work. If you want something millimeter accurate, use LIDAR.