1. ROVER PROJECT #1: Maneuvering the Rover
Andrew Brouillete, Michael Hernandez, and Bach Nguyen
Report by: Bach Nguyen
CSIT Department
Southeastern Louisiana University
Hammond, LA 70401
Contact Number: 985-662-2106
Contact Email: bach.nguyen-2@selu.edu

2. ABSTRACT:
This project is done to demonstrate our understanding of using the DFRobot V1.2 Motor
Shield. By controlling the signal from the Arduino to the motor shield we were able to maneuver
it in 4 directions. Here is the list of directions: backward, forward, left and right.
INTRODUCTION
At the most basic level, electric motors exist to convert electrical energy into mechanical
energy. This is done by way of two interacting magnetic fields -- one stationary, and another
attached to a part that can move. A number of types of electric motors exist, but most BEAMbots
use DC motors1 in some form or another. DC motors have the potential for very high torque
capabilities (although this is generally a function of the physical size of the motor), are easy to
miniaturize, and can be "throttled" via adjusting their supply voltage. DC motors are also not
only the simplest, but the oldest electric motors. The basic principles of electromagnetic
induction were discovered in the early 1800's by Oersted, Gauss, and Faraday. By 1820, Hans
Christian Oersted and Andre Marie Ampere had discovered that an electric current produces a
magnetic field. The next 15 years saw a flurry of Cross-Atlantic experimentation and innovation,
leading finally to a simple DC rotary motor. A number of men were involved in the work, so
proper credit for the first DC motor is really a function of just how broadly you choose to define
the word "motor."(Seale 1)
BACKGROUND:
Because of these reasons, the dc motor is chosen to use to drive a set of mechanical gear
that is connected to the wheel. This particular set of rover from DFRobot has 4 wheels which are
drive by 4 dc motors.
PROJECT GOALS:

3. The goal of this project are to get familiar with the control system of a 4 wheel drives
rover using. We set up the rover to move forward, backward, turn left and turn right depends on
which function is called in the main function of the Arduino. Also we attempted to do the 8
figure with the rover.
METHODOLOGY
By utilize these following materials we were able to complete the rover and make it
move:
 DFRobot 4 Wheel Drives Kit
 DFRobot Arduino Uno
 DFRobot Motor Shield V 1.2
 9 V power supply
We choose to do a tank control mode for the turning since there are no mechanic part of the
rover that let us maneuver it using the default setup. To use the tank control mode of the rover
we connect the left side motors of the rover to the first 2 slots in the motor shield connector and
the right side to the last 2 slots of the motor shield. To make sure the wire stay connected and not
compromise the power connection between the shield and the motors we twist the wires together
to make one single input to the slot. Below is the picture of the finish product should look like.

4. Here is the code and the description for the functionalities of the rover.
int E1 = 5;
int M1 = 4;
int E2 = 6;
int M2 = 7;
int i = 0;
int j = 0;
void setup()
{
pinMode(M1, OUTPUT);
pinMode(M2, OUTPUT);
}
void loop()
{
figure8();

5. }
void figure8(){
forward();
for(i = 0; i < 4;i++){
forward();
left();
if (i == 3){
forward();
for(j = 0; j < 4 ; j++){
forward();
right();
}
}
}
i = 0 ;
j = 0 ;
}
void forward(){
digitalWrite(M1,HIGH); //clockwise turn right
digitalWrite(M2, HIGH);
analogWrite(E1, 220); //PWM Speed Control
analogWrite(E2, 220); //PWM Speed Contro
delay(1000);

6. }
void backward(){
digitalWrite(M1,LOW); //clockwise turn right
digitalWrite(M2, LOW);
analogWrite(E1, 220); //PWM Speed Contro
analogWrite(E2, 220); //PWM Speed Control
delay(1000);
}
void right(){
digitalWrite(M1,HIGH); //clockwise turn right
digitalWrite(M2, LOW);
analogWrite(E1, 200); //PWM Speed Control
analogWrite(E2, 230); //PWM Speed Control
delay(1000);
}
void left(){
digitalWrite(M1,LOW); //counter clockwise turn left
digitalWrite(M2, HIGH);
analogWrite(E1, 230); //PWM Speed Control
analogWrite(E2, 200); //PWM Speed Control
delay(1000);

7. }
In this code, for each function with the entitled with direction are made of 2 set of function to
control motor set 1 and motor set 2. To be able to move forward, both of the set has to have a
high signal going through it. For it to go backward, the 2 set of motor is set to both receive a low
digital Input from the Arduino. To turn right the first set must be write high with speed slower
than set 2 with low signal and higher speed due to the lack in traction of the tires. To turn left the
same thing is done but opposite with turning right. For the figure 8 we use a counter in a for loop
to control the number of turns the rover make to create a circle of that direction then we add
another counter to stop it from going the other way then start going the other way to complete the
letter 8. To get the traction of the tires are really bad we decided to wrap wires around the wheels
like the picture below.

8. RESULTS
After countless time of recalibration, we finally were able to successfully made the 8
figure even though there are few minor bugs like the traction would not let the rover turns or the
batteries went dead because huge power drainage. So it took us a really long time to get a good
reading on how to modify the turns.
CONCLUSIONS:
We completed the project with a lot of minor setbacks whether it’s the traction of the tires in
which we have to nets wire segments for the wheel to rollover or replacing the batteries that’s powering
the whole system.

9. REFERENCES
Seale, Eric. "DC Motors -- Background and History." DC Motors -- Background and
History. Solarbotics Websites, n.d. Web. 10 May 2016.
"Motor Shield V 1.2." - Robot Wiki. N.p., n.d. Web. 10 May 2016.