Stepper Motor

I bought a bipolar stepper motor for my final project. It will be used for actuating the bubble iris attached with a string. NEMA 17- Body length: 34mm

The principle of a bipolar stepper motor is well explained on the below animation (referenced from link)

why not servo motor instead of stepper ?

Circuit

I used the same circuit design of fab class as shown on the below image. The circuit uses two motor driver IC chip (A4953)

First I fabricated the board using the mods but since I didn't check the firm adhesion of the copper board on the sacrificial layer of the milling machine, the trace had weird shape looks like drawn by hand. Also, when I tried to milling the outline of the board, the double-sided tape started to being detached from the sacrificial layer and I wasn't able to complete the board cut clean.

So, I had to cut out the board manually using the wire cutter and some part of board's edge was teared apart and damaged the trace

To connect the damaged traces, I just soldered a wire between the damaged traces which was the vcc line for the driver board. But when I tried to upload a code through the ArduinoISP, my laptop was not able to detect the ATtiny 44 chip on the board and the chip got very hot that even I couldn't touch it. But I couldn't find any shorted line on the board with multimeter and just assumed that the chip might be damaged. So I replaced only the chip but it still didn't work.

So I made another same board and this time I was able to fabricate the board unimpaired. Now I have two boards which are I call old and new.

Debugging

The problems I found during uploading the code through the ArduinoISP.

Getting the ATtiny44 very hot is happen when I disconnect the power to the board but keep the ISP vcc connected.

After connecting the power and ISP, I was able to upload the code on the motor driver board but the stepper motor didn't move at all

That was because I used the 5V output from the Arduino UNO to power the board and it was not enough to drive the NEMA 17 stepper motor

I supplied 12V to the power jack of the board and the motor started to move

As shown on the above, the old board drained more current upto 0.7A while the new one took 0.5A

Even though the old one was working, the motor speed was significantly different. 60 rpm but the old one looks like 20 rpm.

Test

DC Motor Driver

After making the stepper motor, I built a DC motor driver for my final project. I need to drive 2 DC motors (Fan, Peristatic pump) and decided to make two of this and connect individually.

Ran the fan and it worked!