Control DC motors using Arduino

Hi everyone, I'm working on my graduation project which involves quadcopters, and I need help to control the DC speed motors speeds, as well as make my quadcopter hover at a certain position above the earth.

Any advice is welcomed,

Thanks in advance.

I need help to control the DC speed motors speeds

Easy enough, the analogWrite function is what you need to use. What are you going to use as a motor controller? Make sure you take into consideration the power to weight ratio. The sum of the combined weights must be less than what the motors can provide, otherwise it will not get off the ground.

make my quadcopter hover at a certain position above the earth.

This will require a GPS module.

luhan: I need help to control the DC speed motors speeds ... make my quadcopter hover at a certain position above the earth.

There is a huge chasm between those two problems. If you don't find the first one trivial, I suggest it is unrealistic for you to try to tackle the second one.