Vex motor integrated encoder add ons vex 276 1321 this product replaces the plastic cap on the back of a vex 2 wire motor 393 with a quadrature encoder install this product and connect it to your cortex microcontroller via i2c to receive direct feedback from the motor this encoder provides information on how fast the motor is going how far it has travelled and what direction it is moving vex 393 motor integrated encoder add on pack of 2