For some upcoming work, I needed to drive the quad A1 around without being tethered to a computer. To date, my control mechanisms have been:

• A web interface driven from a computer with joystick attached.
• A nrf24l01 link driven from a nrfusb attached to a computer.

Note, both of those methods involve being tethered to a computer, which makes it hard to be mobile. As a possibly short term solution to this problem, I went ahead and got a bluetooth “gaming” controller for my phone (non-affiliate amazon link):

It turns out the web interface I updated previously works just fine on the phone, as does the javascript “gamepad” interface. The only glitch was that this particular gamepad requires that you manually sweep the analog sticks through their full range of motion at each power on before they start providing correct values. Until then, they act as digital inputs. That can be a little disconcerting when the robot starts running ahead at full speed!