first the lecture..... before you buy, get a data sheet of the device. especially from e-bay.
look at the device, what are you actually buying, ? google that,
l298 arduino
l298n arduino
l298 I'm feeling lucky
on each one, hit images and look at the pretty pictures. find the exact match. find out what they say about it.
if you find a lot of posts of 'help, no documentation...' do not buy that part.
I got a great delay timer... has a relay and a bunch of jumpers uses an IC. maybe someone can help ?
the supplier used nail polish and removed the label. I need to identify the chip. it has 14 pins. 7 on each side, looks like a caterpillar.. there is a dimple in near one corner...... for some odd reason, on one has been able to identify the chip.
interestingly, on e-bay ALL the photos from ALL the various suppliers show different views, you can tell it is not the same photo copied, all have the same erased chip label.
back to your chip. the L298n is an H-bridge. so it allows you to run your motor forward and backwards.
you are using a pump. you do not need to run it backwards. so the functionality of the device is lost. not needed.
you have a pump. you can A) use a common FET or transistor and power the unit in an ON/OFF fashion very easily.
or B) you can use a common FET or transistor and PWM the unit to control speed.
or C) use that board.
bottom line, that device is not required and offers no particular benefit in the grand scheme. it does save you from using a resistor and a fet and soldering.
alas, you have it, and want to use it.
understand that most of the data will be for steppers. that requires actually using the H-bridge.
for a one direction motor, you do NOT use the h-bridge, you never reverse the polarity of the coils.
so, connect your 12 to the power input,
connect the motor on out1 and out2
with the enable jumpers in place, IN1
motor will spin.
move wire to IN2 and the motor will spin the other way.
alternate, swap leads on OUT1 and OUT2 and connect 5v to IN1 the motor will spin in reverse.
now, back to the duino.... you have to figure out how to connect your duino to the ground of that board and some way to connect an output pin to that IN1 pin.......
bring your arduino pin high and the motor will spin.
bring it low and the motor will stop
pwm your output and the motor speed with change.
by the way, if you used an FET, it would take one pin, ground and you would either bring that high to run, or pwm to vary speed.
off to get my 3rd cup of coffee.