Mindboards

I'm trying to build a robot that would detect the brightest source of light in a room(light follower). i'll really appreciate it someone could put me through.

Well, as I said in the PM, we really need more details. What is the design of the robot? What sensors are available? Can you be more specific about what you mean by "light follower"? Do you want the robot to follow a flashlight around?

am building a 3 wheeled tribot that uses its light sensor to scan its environment and detects the brightest source of light . The robot then moves in the direction of the light and it also gets to avoid obstacles in its path by using an ultrasonic sensor. the source of the light could be anything including a "touch light".

I still need a lot more details to give specific help.

Here is what it sounds like your robot is designed like:

Standard TriBot, with a light and ultrasonic sensor pointing outwards (and perhaps the light sensor it pointing slightly upwards).

Here is what it seems you want it to do as soon as you start the program:

Turn 360* around, while taking ambient light sensor readings.
Determine where the sensor saw the light the brightest in the rotation.
Turn towards the position where it saw the brightest light.
Drive straight towards the light. Do you want it to keep fixing on the light, or do you want it to just drive as straight as possible?
If the ultrasonic sensor "sees" anything within a certain range, give priority to getting around the obstacle, and then resume going towards the light (again, what type of path determination do you want to use?).

So what specifically do you need help with?