Question

How to make an obstacles avoiding robot?

Answer 1

You could use an arduino uno rev 3 version. Along with photoresistors and hcsr04 module, sense the distance and the light being recieved, and using a l293d ic, make a h beidge motor driver circuit, which will help you make a circuit controlling 2 dc motors at once. You could so put he hc04 module for bluetooth and use it to connect the arduino to your phone and control it through the sensors present on your phone like accelerometer, proximity sensors amd gravity sensor etc .

Answer 2

You can uno rev3+ hc -sr04  + 2 servos .
you can find code for hc -sr04 at arduino website and schematic attached with this answer.
hope it helped!