i´ve read many posts in this forum and took a good time googling but but i´m still not sure what specs the steppers to use with the L298N should have. Lets say i´m powering the steppers with 12V.
I´ve learned that just the current is limiting, so i can use a stepper rated at 2V with my 12V setup, right?
But as there is no current limiting this imaginary 2V stepper should be rated below 333mA to stay below the max 2A (with very good cooling etc) of the L298? But that 2A would fry the stepper?! Or do i have to use resistors in series with the windings to limit the current to that rated current and waste some energy?
I think you're approaching it backwards.
Find motors that will do the task you need, then find a stepper driver that will support them.
Steppers come with 2-coil and 3-coil windings.
L298 will support up to 2A per winding; at higher currents make sure you have a design with good heat sinking.
You can find plenty of cards that look similar to this:
Just to make things clear: I went to ebay and bought a lot cheap of chinese stuff to experiment with. Some sort of sensors and actuators, and two of these dirt cheap L298N stepper driver boards similar to the one in your link. At a price just over 2€ i couldnt do wrong Now i´m looking for evenly cheap steppers to use with that boards. There is no real task yet, just playing around and thats why it should be kept cheap. The question now is what stepper is usable? I might get some printer steppers or what ever with some specs like 3V 0,5A or what ever and i wanted to know wich one, or better: wich specs will do with that board you mentioned..
If a motor has a current limit of 0.5 amps and if the coil resistance is such that it only requires 6 volts to supply that current then connecting it to 12v will overload the coils and may let the smoke out.
"Proper" stepper motor drivers (i.e. NOT the L298) have the facility to measure the current flowing into the coils and to limit it. That allows them to be powered with higher voltages without harming the motor. The higher voltages allow the motor to maintain its torque at higher speeds by forcing the current through against the inductance of the coils.
With an L298 you have to match the voltage to the limits of the motor coils.
Using a lower voltage won't damage anything but may result in poor performance.
i know there are "better" motor drivers but i wanted to try the cheap stuff and have some fun with it. thank you for the explanation, makes things a bit more clear.
So, if i´ve got an unknown stepper where to start at? 5V? just coming back from the "electronics graveyard" with the infamous STH-39D1126 stepper out of an old HP ScanJet 6100C scanner. No infos on google, just questions. at least i found a video on youtube where someone is driving this motor with 5V. Label says 4.1ohms and no more..
my first project idea is to use steppers to adjust big variable capacitors, this wont need much torque but some precision.
found some info on the scanner power supply: "OUTPUT FOR MOTOR: 10V 0,4A"
and i found a nice UDN2916B dual H-bridge IC.. so why not using the scanner power supply and the stepper controller and just control that with the arduino? do i have to connect the IC´s ground to the arduino ground?
PSU and controller are on the same board and in a nice enclosure..
The signals need a common ground with the Arduino. You will need to consult the datasheet to see if the power supply ground also needs to be connected.
i got a bit confused which pins i need to connect? E1, E2 to 5V, GND and?? which pins are needed to control the motor?
the I01,02 and so on pins are for current limiting?
on the L298 boards there are just input 1-4..
That's actually not totally a joke, many datasheets take a lot of reading to work
out the implications. You certainly need to read it twice, once to see if it can do
the sort of thing you want to do and once to see what limitations it might have for
your particular use of it (the devil in the details). If there's a recommended circuit
then use it, they've done all the thinking for you!
Now i´m looking for evenly cheap steppers to use with that boards. There is no real task yet, just playing around and thats why it should be kept cheap. The question now is what stepper is usable? I might get some printer steppers or what ever with some specs like 3V 0,5A or what ever and i wanted to know wich one, or better: wich specs will do with that board you mentioned..