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Stepper Motor Tester

Whenever there is a requirement to test a Stepper Motor performance or coil connection sequence, we need a stepper motor controller board, a variable DC power supply source, a logical signal generator ( or a microcontroller ) and separate power supply for logical system etc.  Still this total circuit makes confusion with so many wire connections.  The circuit used here is quick, low cost, handy, compact and requires only one DC power supply input.  The stepper motor driver used here can handle up to 2A  stepper motor.

Stepper Tester-THUMBNAIL_WIX.jpg

A4988 module (breakout board) is a small size, 2A bipolar stepper motor driver, which has on board adjustable current limiting, over current protection, short circuit protection and five micro-steps resolutions.  The module can be operated from 8VDC to 35VDC for Stepper motor and 3VDC to 5.5VDC for logical system.  Only two pin interface is used to control the direction and step of the stepper motor.

Refer full circuit diagram: 

StepperMotorTester NEW.png

Testing : Assemble all the components as per the above circuit on a PCB.  Connect all jumpers J1 to J7.  Connect 4 LEDs to the 4pin connector with 3.3K resistance in series for each LED. Connect DC power supply and switch ON the power switch.  The 555 IC is connected as Astable multivibrator mode and generates pulses and the pulses are fed to the Step of A4988 module.  The speed of the pulse train may be observed with the help of Blinker LED connected to pin 3 of 555 IC. Due to the input pulses to Step pin of A4988 module, the 4 LEDs glow in sequential pattern, indicates the circuit is working properly.  By changing the variable resistance VR2, the speed of the LED pattern varies.  With disconnecting and connecting Jumper J1, we can achieve two speeds of pulse trains from pin 3 of 555 IC and accordingly speed of the LED pattern.


Usage : Switch OFF power supply, disconnect 4 LEDs and then connect (4 wires) a Stepper motor to the 4 pin connector.  Now, switch ON the power supply to the circuit.  Adjust VR1 to get the required voltage to the stepper motor, which may be measured at TP3 w.r.t. ground.  The Stepper motor rotates in one direction (either CW or CCW).  Now, disconnect  the Jumper J6 and check that the motor rotates in opposite direction. By connecting and disconnecting jumpers J3, J4 and J5 the rotation of angle of the motor shaft varies for each step pulse input as described in the table below.


This circuit works upto 12VDC power supply.  To use different power supply or more than 12VDC (upto 35VDC) to the stepper motor, disconnect Jumper J7 and connect +ve power to the TP3 pin and –ve power to ground line of the circuit.


To control the stepper motor from other source, like microcontroller etc,. disconnect jumpers J2 and J6 then connect step control to TP1 and direction control to TP2 pins respectively.


List of Components:

1 x LM338T Voltage Regulator

1 x 7805 5V regulator

1 x 555 Timer IC

1 x A4988 stepper motor driver module

3 x 1N4007 dioides

2 x 20K preset (volume control)

1 x 1K resistance

2 x 2.2K resistance

2 x 3.3K resistance

5 x 4.7K resistance

1 x 47uF 50V capacitor

1 x 22uF 16V capacitor

3 x 10uF 50V capacitor

1 x 2.2uF 16V capacitor

1 x 0.1 disc capacitor

1 x 0.01 disc capacitor

1 x 3mm red LED

1 x 3mm green LED

1 x 3mm yellow LED

1 x 2A(or more) SPST switch

Berg strips, connectors, power supply, stepper motor etc.



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