// Stop analogWrite(M1_SPEED, 0); delay(2000);

HW-130 Motor Control Shield for Arduino: The Complete Hardware Datasheet & Engineering Guide

Can drive up to 4 bi-directional DC motors or 2 stepper motors (unipolar or bipolar).

#include <AFMotor.h>

void setup() motor1.setSpeed(150); motor2.setSpeed(150); BT.begin(9600);