Motors with an encoder (rotation angle sensor) are gaining more and more popularity due to a smoother and more dynamic start from a standstill. We have released a board that allows you to upgrade QS138 to an encoder.
This is an ABZ+PWM encoder for 1024 pulses. The set includes a board, wires with a connector, two magnets of different thicknesses, and plastic adapters for installation.
Cost $30. The boards are in stock. Order.