So I've been thinking to make a sonar using Arduino. The idea is to make it powerful to detect distant objects, but for now I want to try it at the scale of an HC-SR04.
My idea is to send a pulse and detect all echoes on a certain amount of time, so I can detect several objects. The problem is that the sensor I mentioned only detects the first object. I thought of making my own sensor using a bandpass filter and an amplitude detector to find where the echos are in time, however I still really noob on electronics. Any idea of where should I begin?
As reference, I'll show an image of how an early radar works, which is sort of what I'm thinking about.
At the end, you'll get a array of the distance of each peak and each index corresponds to an echo and, in theory, an object. On a bigger scale or on outdoors should work fine. On indoors may have trouble due to the sound bouncing everywhere.