Arduino hall effect and dc motor

Hello,
I want to do this circuit, a hall effect sensor will measure will measure the returns of a small tire then arduino take the returns measured per minute and with the speed measured, do some calculations and the result will be the speed of a 12 dc motor. Here i have a guestion. Will arduino have problem if i give it 12 volt to control the motor, or i will give the electricity that motor needs from an other external source directly to motor ?
thank a lot

** I'm am new to electronics please help me :sweat_smile: :slight_smile: :blush:

Will arduino have problem if i give it 12 volt to control the motor

Only if you connect the motor directly to the arduino, which you should not do. You need a motor drive circuit of some sort.
http://www.thebox.myzen.co.uk/Workshop/Motors_1.html

i will make this circuit, and then it will be controlled by arduino but the source will be exernal if i understood well. right?

but the source will be exernal if i understood well.

If you are powering the arduino from an external source into the power jack you can use the same voltage source to connect to the motor's supply.

I will use 12 volt from tractor plug to connect the arduino.. so as you said i do not need the circuit