Today I got my first "missing" parts to propel my ball 🙂 I'm going to make a simple and cheap speed controller by using two 30A brushed plane ESC, less than $9 each.

The problem with these ESC's is that they don't have a reverse mode, so I have to make a kind of hack to be able to reverse my ball.
I found this nice Open-source Servo Switch that I'm going to modify and use to switch the polarity of my DC motors, thus making the motors go reverse.
All parts; ESC's, relay, ATTiny, some capacitors and resistors will cost about $30, witch is approx $20 less than a comparable 2 channel speed controller with a RC interface!

Hopefully in a couple of days I will get my two 500 RPM DC motors as well, then I will start to experiment with my propel system!
BTW I also have a test print of a motor mount, that I've made in FreeCAD, waiting to be delivered 😎