Step Motor With Driver Shield

Step Motor Test Photo

Let’s control a Step Motor with a custom-designed shield. It’s just like the Motor Driver Shield, but cheaper and more fun because we make it ourselves.

Driver Shield Parts

Total BOM cost for this shield is $8.63, plus $8.40 for the board, totals $17.04.


Qty Source Part# Description Price Comments
1 Mouser 511-L298 Motor / Motion / Ignition Controllers & Drivers Dual Full Bridge $4.67 Datasheet
8 Mouser 821-1N4001 Rectifiers Vr/50V Io/1A T/R $0.16 Datasheet
3 Mouser 651-1935161 Fixed Terminal Blocks PT 1.5/2-5.0-H $0.34 Datasheet
2 Mouser 647-UVR1E101MED1TA Aluminum Electrolytic Capacitors – Leaded 25volts 100uF $0.04 Datasheet
2 Mosuer 660-MF1/4DC1002F Metal Film Resistors 10K 1% 100PPM $0.04 Datasheet
1 Sparkfun PRT-10007 Arduino Stackable Header Kit $1.50


The L298 Motor Driver is the chip at the heart of this all. This is the one that handles all the current, allowing us to make small signal inputs with our Arduino to control motors of large voltages. This part is also available from Sparkfun for ~$1.50 less, so if BOM cost is important, you can get it there.

Diodes are needed to protect against reverse pulses coming from the motors back onto the rest of the circuit and ruining things.

Screw terminals for attaching the step motor wires and external power.

Capacitors are needed to even out the flow of power.

The board has a pair of switches separate from the motor circuit for me to give inputs into the Arduino that the sketch can use for whatever it wants. These resistors are there to pull down the switches to ground. It turns out that using these is a bad idea. Instead, I should have used the Arduino’s internal pull-up resistors and then connected the switches. In a future revision, I will change that and remove these resistors.

The trick to making a shield is getting these great stackable headers which stick through the board into the Arduino, and let you attach something into them above.

Other Parts

Qty Source Part# Description Price Comments
1 Sparkfun ROB-09238 Stepper Motor with Cable $14.95
1 Sparkfun BOB-09540 Breakout Board for L298N Full-Bridge Motor Driver $2.95

The Sparkfun motor is a great motor to start out with. Sturdy, powerful, priced right. That said, this setup will work with any bipolar step motor.

When working with this on a breadboard, having the little breakout board for the L298 is critical. We won’t need it when the shield is done, though.

Background Reading

First, it’s good to be familiar with this stuff:


L298 Motor Test V2.sch

Fundamentally, we are building the “Reference Circuit” from the L298 data sheet onto an Arduino Shield.


See the entire sketch on github:Step Motor Simple Test

The test software is simple. We use one button to turn left, and the other to turn right. Pressing a button turns the motor 180 degrees in the indicated direction.

void loop(void)
// read the pins
int sw1_reading = digitalRead(sw1_pin);
int sw2_reading = digitalRead(sw2_pin); 

// if only one switch is high, turn the motor the
// corresponding direction one half revolution.
if ( sw1_reading && ! sw2_reading )
if ( sw2_reading && ! sw1_reading )

Circuit Board

Following the advice in the Beginners Guide to Arduino Shield PCB, I then laid this circuit out using EAGLE, and send it off to for fabrication. $25 and 14 days later, I have three of these handy purple boards in my hands for all my step motor driving projects.

Note that this will also drive a pair of regular bi-directional DC motors.

L298 Motor Test V2-laen

The Future

This whole setup could be made even smaller and cheaper by using an Arduino Pro Mini from Sparkfun. The next revision of this board will use a 24-pin socket to stick the Pro Mini onto the board.


Filed under Arduino, L298

4 responses to “Step Motor With Driver Shield

  1. lunwala

    A thousand and one thanks. The circuit diagram is a big help.
    once again thanks a million

  2. pukhraj

    is this circuit properly working???

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