Each Stepper needs at least 2 pins, step and dir probably also the enable pin but perhaps that's not essential.
You will also need at least 1 pin each for:
3x End Stops,
Hot end PWM (optional)
Fan PWM (optional)
Heated Bed PWM (optional)
Also you will not be able to do microstepper with the ULN2003 very easily so you will be more limited in accuracy.
Why build a printer with such limitations? How are you going to source all the mechanical parts for under $30?
Also as langwadt said, those steppers are terrible.
I've already got all the steppers, all the driver boards, the extruder and the arduino ordered for 16 bucks.
Linear sliders will be pulled out of a printer.
The rest will be made of plywood, except for the bed which will be made of 6mm plexi that i got from an old LCD monitor.
Accuracy is not important at this point because it can be improved once the printer is working.
As the title suggests i'm making a 3D printer but i'm making mine under 30 bucks and it will (i hope) be controlled by an Arduino Nano.
I'll be moving everything with the el-cheapo 28BYJ-48 stepper with the ULN2003 driver, Y and Z will have two on each and X will have one as it will be moving a smaller mass.
I did a quick google search but couldn't find anything readily available for my little project, so here i am asking for help.
Untill my stuff arrives i hope to have most of it sorted out and at least the chassis ready for parts.
From what i see Arduino nano has 16 I/O so it will all be taken up by the motor driving (4 for each stepper (X, Y, Z and extruder))
Dunno if i'll be able to make it work but i'll try.
I'm a newbie when it comes to micros so all help is wellcome, especially reading the G-code and interfacing the software.
Thanks.
Those steppers doesn't have enough torque to pull the skin off a pudding, and if you don't use a high voltage
constant current driver you'll have to also have to run them very slow
A 3D printer has already been made using these steppers ( look up ToyRep ) so they have plenty of power for a desktop project, for my use the speed is acceptable and will not bother me as long as the printer itself works.
More powerful steppers are a better solution but they are much more expensive and since i can not buy what i can not afford renders those steppers useless, thus in my case making this budget 3D printer faster than it would be otherwise.
Also exploring new grounds and pushing things to their limits will serve as a reasonable example of what can be achieved for under 30 bucks.
are the L298N better for stepper motor control ? they are still very cheap.
They might be a good choice for future improvements, since the the cheap unipolar steppers can be modified to be bipolar, in which case the L298N board would work out very well.