I am trying to design an object tracker (only left and right) and I am using phototransistors by using two analog inputs.I have to explain my problem more clear.When I turn power on servo tracks object but after a while sometimes pic resets itself or servo motor suddenly stops..What do you suggest? Here is my design.When you see the design there is a lcd.I use it for watching the values of analog input.When servo rotates,brightness of lcd changes (getting brighter or darker)...I think thats another weird thing...

here is my design.

 

The image is much too small to see anything. Could the problem have to do with using small batteries? That would explain the LCD dimming and the PIC resetting.

 

In addition to the comments by beenthere, you may want to make certain that you have adequate power supply filter capacitance. You might benefit from the use of a large valued electrolytic capacitor. A 10 ufd at 16V would be a good start though you could go larger if you have a larger value laying around. You also need to add a 0.1uFd/25V ceramic capacitor to bypass/filter the higher frequency noise that is probably being induced onto the power supply lines by the servo. The 0.1ufd will do the most for you if you locate it physically near the PIC's power and ground.

You will also need to make sure that you have good ground line connections throughout your circuit. Keep the ground connections as short as practical.

hgmjr

 

my battery is that
switching adapter
input:ac 100-240V-50hz 0.36A
output:dc 5v--2.5A

Does it make problems?

 

If the servo pulls significant current, it will cause problems. Remember that we can't see any details about the supply, isolation from the load, filtering, and so on.