This has been in my queue for quite a while (and I’m pushing it out now with no pictures, oh darn). When I was in college we were working on a quadcopter. I think our descendants are still working on the same one. When I was there we had an ardupilot board and were making a frame, tuning the hardware. One of the optional extras that the ardupilot code can take is an ultrasonic sensor. The sensor they use outputs an analog voltage. The sensors I had around used a trigger and echo pin. Rather than modify the ardupilot code I chose to throw a pro mini at and adapt my sensor to what the ardupilot expects. Here is my code for how to make a DYP-ME007 act like a Maxbotix ultrasonic sensor. For anyone who wants to get away with a cheaper ultrasonic sensor here is my code, if it looks simple that’s because it is.
ultrasonic adapter for quadcopter