This project refers to an Arduino sketch which uses an ultrasonic sensor for calculating the time return of the ultrasonic signal emitted by the sensor and the object reflecting the signal back. Then, with the help of appropriate physicomathematical formulas, it performs calculation of the distance between the sensor and the object causing the reflection signal. Also, the system includes a piezo speaker used to produce a tune when an object is detected too close nearby. This system could be used in security doors, on cars as a helper to park or anywhere else where distance at close proximity is important.
For more information you can get the project itself:
`vehicle_parking_alarm_via_ultrasonic_distance_ping_sensor‘
Below the image of the application:
Efstathios Chatzikyriakidis 
Be well.
Probably this project will combine my three loves: ecology, agriculture and computers… Thanks for the ideas! Keep up the good work you do!
I am glad that I helped in some way with your automatic watering can.
It is quite interesting.
I also suggest installing a moisture sensor to irrigate only those in need of water, not all.
As for the ultrasonic sensor, it will work fine.
Only take care that you do not use transparent glass to do the testing.
I appreciate that you mentioned me in the article on the ultrasonic sensor.
Be well. Keep us informed!
You posted it just in time! I was looking for a way to make my “watering can” automatically recognize when there is an object to be filled…