Hi!
First, THANKS to all who have help me with my robot in the pass, although I've lose in the RoboCupJunior Local.

I lose in the Local competition in the RoboCupJunior.
The robot I've made broken down in the 4th match.

I'm a secondary school student. I have used the 89C52 MPU for less than 1 year, I program in assembly. All sensors including Visible light sensor, Infra-red sensor, Ultrasonics sensor and also the "motherboard" (one 40 pins chip socket and 4 9-pins jumper) are hand-made,all by one soldering iron.

DIY is not "stable". The circuit board I made often broken down. That's fine, I've backup it for 3.

Now I want to know the "pros and cons" of using a SERVO motor or a normal burshed DC motor (Tamiya, Japan) WHICH ONE IS BETTER FOR SUCH A SECONDARY STUDENT LIKE ME? (I don't have much $...so I choosed the Normal DC motor.)

Servo: $x00
small dc motor: $x0

The DC motors "waste/need" many power, so my motor driver often broken down (counter EMF? I added diodes, capacitors, coils, and "waxed" the driver board)(it mainly composed of transistors, TIP41C TIP42C)

THE VISIBLE LIGHT SENSORS ARE AFFECTED BY THE MOVEMENT OF THE MOTORS, NOTE THAT THE POWER SOURCE IS SEPARATED. HOW CAN I PREVENT THIS?

thanks for all helps and information!