Dual Bipolar Stepper Motor Shield for Arduino (A4988)

Generally, it's not an easy thing to drive stepper motor(s) with Arduino; but with this stepper motor shield, you can easily control 2 stepper motors via just 4 digital I/O’s. This board is compatible with the Arduino UNO R3, and get direct support with Xbee and Xbee form factor Wi-Fi, Bluetooth and RF modules. Easy connection of cables via screwless PC terminals. Each stepper motor has a code switch for adjusting driving modes, to obtain different rotational speeds.The interfaces of the board include extension 6 channel Analog I/O, 10 channel Digital I/O & I2C. 

The driver IC is using the most popular A4988 which is widely used in 3D printer and CNC machine.  The A4988 is able to control one bipolar stepper motor at up to 2 A output current per coil.  With one mega and DFRobot's mega expansion shield, a 3D printer control board can be built so much eaiser.  Here are key features for A4988 stepper motor drivers

• Simple step and direction control interface
• Five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step
• Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor’s rated voltage to achieve higher step rates
• Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
• Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection
• Short-to-ground and shorted-load protection

• Easily control 2 stepper motors with only 4 digital I/Os.
• Fully compatible with Arduino UNO R3、Leonardo、Mega and supports XBee，XBee Wi-Fi，Bluetooth and RF modules.
• 6 Analog / 10 Digital & I2C
• Screwless connection with press and connect. For detailed pin mapping please refer to product wiki.
• Each stepper motor has a switch for mode switch to obtain different rotational speed. Step modes include 1, 1/2, 1/4, 1/16.
• Wireless switch next to Xbee. "PROG" mode for USB uploading and "RUN" mode for wireless communication.