I've been building my quad using an Arduino as a FC and the thing is that I am not able to set the PID gain values correctly thus whenever I try to start lifting it, it goes out of balance and starts spinning or turns upside down on one side. Also, I've noticed that mostly one motor spins much faster than the rest, what should I do? does anybody know how to set these values correctly in one go?
The code I'm using is from www.brokking.net

Guys now s a new problem more intensified push from one motor, seems like it wants to do all the work by itself thus turning a hell lot faster than the rest of them. What could be the problem and solution?

It will be hard for a beginner to build a drone with arduino as Fc.I recommend you to use kk2.1.5 flight controller.It is very easy to configure.

Well that's not an option i have

Check your motor bearings.Bad bearings may reduce the performance.It will consume more power.which motor you are using

Which arduino you are using?

Uno

i have not looked at the code in detail - but why not use multiwii ?

it is a mature project and lot of us can advise. your existing setup should be fine

Yes i was thinking about giving that a shot now, will do it tonight and  post updates here

Obstacle avoidance system can be made with arduino.

I have the code

Multiwii is getting too complicated, cant be done now
Why do you think 2 motors are running faster than the other two.

I need your help in setting values of throttle range
my throttle , roll pitch and yaw axes of transmitter do not go from 1000 to 2000 so i need some help about how to set the multiwii code according to it?

In stall position there would gyro drift in sensor which could be reason for your problem. Try to fly the quad. During flight it wont effect that much.
I think two oppsite motors are spinning trying to yaw the quad. If that is the case try lowering "I" constant for yaw which is also a reason for yaw.