I yet have to buy the power unit and it will be 12 or 15 volt.
Not sure what i need for it depending on answers here.
What I would like to do is to control is a normal DC motor (12volt)
In such a way that an arduino controls the voltage to the motor (serial out ?) control bij mosfet transistor ?
But also power the arduino itself rom that same power unit.
Normally i powered small detector things who were powered directly from the Arduino.
This time i'd like to control something that requires a bit more juice then the Arduino itself.
So how would such a schema look like, i have no background in electronics.
Its a normal DC motor not a stepper motor
If possible in schema not sure how hard that is to revert power as well ( switching + - to motor to let it turn back)
If you want to control DC motor speed and direction you need an H-bridge motor driver. There are many of them available. To choose the right one you need to know not just the motor voltage but how much CURRENT it needs.
If you only want to control speed but not reverse the motor then a logic level MOSFET will do it. The circuit is simple, search for "Arduino MOSFET pwm" for many examples.
A 5V DC-DC converter connected to the 12V supply will run the Arduino.
Hm if I use 4 MOSFETs shouldn't it then be possible to use 2 pins like one up other down for direction. have a circuit that looks like a h bridge (thanks for that term) and use pwm to control speed ?
Certainly you can build your own H-bridge if you like. It will take a few more components than just 4 MOSFETs but there are circuits available all over the internet. But you'll still need to know how much current you're trying to switch to choose the right components.
"just time to build is more expensive than module"
The reason I suggested buying one is there is a
lot you need to know about H-Bridges, not the
least of which is SHOOT-THROUGH.