DIY 3D printer part 8 - making a UNIPOLAR stepper motor driver for my 28BYJ-48 based extruder!

Get 10 Arduino sized PCBs for $5 at https://www.pcbway.com/ ! In this episode of my DIY budget 3D printer we're building a custom, GRBL and Marlin compatible, UNIPOLAR stepper motor driver to control the 28BYJ-48 based extruder!!! Chronic UniStep as I've decided to call it is just as easy to use as the ubiquitous A4988 for bipolar steppers - except it's a better fit for high-impedance unipolar motors like the ones you can salvage from e-waste! If you guys want me to open-source this invention let me know! Also I might have to do a seperate video to explain why you would use a dedicated unipolar stepper motor driver instead of just converting unipolar motors to bipolar like I had planned to do with all of mine...

Here's the test code I used:
Bidirectional speed control potentiometer:
https://drive.google.com/file/d/1Sr5E...

Affiliate links* to the ICs and some parts I got for this printer:
10pcs CD4017 decade counter IC (SMD version): https://s.click.aliexpress.com/e/_Dln...
10-20pcs ULN2003A SOP-16: https://s.click.aliexpress.com/e/_Dks...

5pcs A4988 stepper motor drivers: https://s.click.aliexpress.com/e/_Apv00b
Cheapy hotend kit: https://s.click.aliexpress.com/e/_A217Gn
Arduino mega 2560: https://s.click.aliexpress.com/e/_AnxG2B
4010 turbine fan: https://s.click.aliexpress.com/e/_AnUid9
100k NTC temperature sensor for heated bed: https://s.click.aliexpress.com/e/_A9cOwJ
10m nylon coated fishing line: https://s.click.aliexpress.com/e/_9HKabt
Keep in mind I got a few of these items during sale, so the total might well be above $50 now (especially with inflation)


* if you decide to purchase something through an affiliate link I may receive a small commission
-------------------------------------------------------------------------------------------------------
Support this channel on Patreon: https://www.patreon.com/user?u=81848920

Follow me on Twitter for random updates and personal opinions on different topics: @chronic_atronic

Join r/chronicmechatronic for occational peeks behind the scenes, or general project discussion!

Get my best photographic works on Shutterstock:
https://www.shutterstock.com/g/Floraf

Or download free stock photos from my profiles on Unsplash:
https://unsplash.com/@floraf
https://unsplash.com/@clicabout
-------------------------------------------------------------------------------------------------------
Additional sound effects from https://www.zapsplat.com