In this tutorial you will see how to control the Torque or Speed of your Brushless DC motor using SOLO and Arduino in closed-loop sensor-less manner . In this tutorial Arduino acts just like a commander and sends some PWM pulses to increase or decrease the Speed/Torque. If you like you can use just a potentiometer instead of Arduino. 

The full Article:

https://solomotorcontrollers.com/how-to-control-speed-or-torque-of-your-brushless-motor-with-arduino-using-solo-closed-loop/