SUMBA - a sumo robot and my first project

Hi everybody, as some people allready know i am new to LMR and robots all together, meaning this is my first robot.

It was originally going to be a holiday project but when my science teacher gave us a holiday assignment that had rather open criteria, the bot for fun got given 4 weeks to be finished, so now with a bit over 2 weeks left I almost have the entire bot assembeled.

The chasses dimensions are 15cm wide X 15cm long X 5cm high

At the moment all i have is the unfinished chasse asembled (I still need to add holes for the wheels and skrew down the motor), and the code that i believe is finished, it may need some editing once i hook up the senors and test the whole thing out. 

here is a fritz of the wiring it will be more compact when actually put together, those are 1K resistors.

here 

also with the code im using PWM to control the motors because I have an NPN transistor between the motors and the batterys and i dont want to burn out the motors.

Here is the code:

(EDITED CODE) changed after seeing the comment by bdk6

CHANGE LOG: when one motor is running the other is set to off

#define RIGHTDC 5

#define LEFTDC 6

#define MIDDLEIR A0

#define LEFTIR A1

#define RIGHTIR A2

#define DANGER 1000

#define HALFSPEED 127

#define STOP 0

void setup() {

  pinMode(RIGHTDC, OUTPUT);

  pinMode(LEFTDC, OUTPUT);

}

void loop() {

  if (analogRead(MIDDLEIR) < DANGER) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if (analogRead(RIGHTIR) < DANGER) {

    analogWrite (LEFTDC, HALFSPEED);

    analogWrite (RIGHTDC, STOP);

  } else if (analogRead(LEFTIR) < DANGER) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, STOP);

  } else if ((analogRead(LEFTIR) < DANGER) &&

             (analogRead(MIDDLEIR) < DANGER)) {

               analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if ((analogRead(RIGHTIR) < DANGER) && 

             (analogRead(MIDDLEIR) < DANGER)) {

               analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if ((analogRead(LEFTIR) < DANGER) && 

             (analogRead(MIDDLEIR) < DANGER) && 

             (analogRead(RIGHTIR) < DANGER)) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if ((analogRead(LEFTIR) < DANGER) && 

             (analogRead(RIGHTIR) < DANGER)) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else {

    analogWrite(LEFTDC, STOP);

    analogWrite(RIGHTDC, HALFSPEED);

  }

}

(OLD CODE)

#define RIGHTDC 5

#define LEFTDC 6

#define MIDDLEIR A0

#define LEFTIR A1

#define RIGHTIR A2

#define DANGER 1000

#define HALFSPEED 127

void setup() {

  pinMode(RIGHTDC, OUTPUT);

  pinMode(LEFTDC, OUTPUT);

}

void loop() {

  if (analogRead(MIDDLEIR) < DANGER) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if (analogRead(RIGHTIR) < DANGER) {

    analogWrite (LEFTDC, HALFSPEED);

  } else if (analogRead(LEFTIR) < DANGER) {

    analogWrite(RIGHTDC, HALFSPEED);

  } else if ((analogRead(LEFTIR) < DANGER) &&

             (analogRead(MIDDLEIR) < DANGER)) {

               analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if ((analogRead(RIGHTIR) < DANGER) && 

             (analogRead(MIDDLEIR) < DANGER)) {

               analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if ((analogRead(LEFTIR) < DANGER) && 

             (analogRead(MIDDLEIR) < DANGER) && 

             (analogRead(RIGHTIR) < DANGER)) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else if ((analogRead(LEFTIR) < DANGER) && 

             (analogRead(RIGHTIR) < DANGER)) {

    analogWrite(RIGHTDC, HALFSPEED);

    analogWrite(LEFTDC, HALFSPEED);

  } else {

    analogWrite(LEFTDC, 0);

  }

}

If you see anything that you think i could improve on please tell me, as i said i am a beginner and i would love any help that can be supplyed to me.

(MAJOR EDIT!!!)

i haven't updated this in a while so here is what has happened with my bot.

First off, the gear box that i was going to use had shafts that were  3 ml in diameter and they did not fit my wheels, so i looked for new wheels and coudnt find any to the right size so instead i got new motors, this leads to my next problem.

i looked for the motor on the website of the place that my sister works at and got her to buy them for me, i stuffed up and didnt look at the dimensions and i got motors that were much larger than i originally thought.

to combat this problen i got rid of three walls and the roof to make room for the new motors and battery pack.

i also edited the front of the bot so that the sensors had somewere to be placed seeing as they were originally going to be attatched to the roof.

finally, when i was about to finish the robot i found the the cable ties i had bought to hold the motors down weren't long enough.

by tommorow i should have the robot done and be ironing out the bugs so expect videos and pictures soon.

 there will also be updated code as i do not need to use PWM any more