For the encoder, the protocol will be as follows:
e<space><left_encoder_ticks><space><right_encoder_ticks>
For the ultrasonic sensor, the protocol will be as follows:
u<space><distance_in_centimeter>
For IMU, the protocol will be as follows:
i<space><value_of_x_quaternion><space><value_of_y_quaternion>
<space><value_of_z_quaternion><space><value_of_w_quaternion>