Trying to find the simplest way to move a servo using an android phone via USB. Have tried a few apps, but so far no luck.

The premise for the latest attempt is use of an audio output (via OTG adapter) to drive a servo or servos.  "PWM Buddy" sounds great for what I want to do which is:

Guide a glider toward a pre-determined destination using a tiny (PVG100 Palm) android phone.  I'll add a microcontroller in between if need be (tiny85?) but in a perfect world I'd just be able to plug it in direction.  The idea was to control a single servo operated rudder and carry the tiny phone along.  If I can do that, I can use the phone's internal camera and plethora of sensors to manage all kinds of data- but it all depends on getting that servo to work somehow.   Yes, I could use a bluetooth sheild or module or whatever but since I'm pulling power from the USB-C anyway, it would be great if I could just get that servo going via the same means.  Just trying to keep it simple.

Other options include this "ESC & Servo Controller" which also sounds pretty great but it never detects a device.  (Yes, I loaded the code onto an arduino nano).

I guess it needs a device to be in host mode but that sounds like it shouldn't be too hard.

I've also started looking at various "app maker" apps, but so far nothing has worked to control a servo.

help?