This document summarizes the subsystems of a line following robot, including its power system using lithium ion batteries and voltage regulators, motors controlled by an H-bridge circuit, line-sensing sensors, and microcontroller code for moving the robot forward, backward, and turning. It describes the results of testing where the robot initially overcorrected when following the line but increasing accuracy after slowing the motor pulses. The conclusion reflects on the challenges of the project and designing an affordable learning platform.

1. Line Following Robot
By Elijah Barner, Timothy Moore, Bryan Quiroz

2. Subsystems Block Diagram

3. Code Block Diagram

4. Power Subsystems
18650 Lithium Ion Batteries
Typical Capacity: 3000 mAh
Min Capacity: 2900 mAh
Nominal Voltage: 3.7V
Charging Voltage: 4.35V
12 volt regulator - 7812
Max Amperage output:1 amp
5 volt regulator - 7805
Max Amperage output:1 amp
5V To 3.3V DC-DC Step-Down Power Supply Buck Module -AMS1117
● Operating Supply Voltage: 4.2 V to 10 V
● Output Current: 800mA
● Output Voltage: 3.3 V

5. Motors
SN754410NE - H Bridge
● Operating Supply Voltage: 4.5 V to 36 V
● Output Current: 1100 mA
Digilent 12v motor
● Max Operating Supply Voltage: 12 V
● Output Current: 240 mA
● Torque: 617 g-cm

6. Sensor Subsystems
PmodLS1
● VCC Pin (Pin 6)
● S1, S2, S3, S4 Header
● Infrared LEDs
● Infrared-sensitive phototransistor
OPB704
● Max Collector Current: 25 mA
● Vf - Forward Voltage: 1.7 V

7. Microcontroller
void forward(){
PWMDTY4=speed;
PWMDTY5=speed;
PTT=0x90;}
void stop(){
PWMDTY4=0;
PWMDTY5=0;
PTT=0x90;}
void left(){
PWMDTY4=(speed-decrease);
PWMDTY5=(speed/5); //slow down
PTT=0x40;}
void right(){
PWMDTY4=(speed/5); //slow down
PWMDTY5=(speed-decrease);
PTT=0x80;}

8. Results
The robot follows the line, but it
overcorrects some of the time at an
average of 21 seconds.
We slowed down the pulses in order
to increase it’s accuracy. With the
correction it still makes it around the
course at the same average of 21
seconds.

9. Summary/Conclusion
This was a very hard project but it was a sum of all that we learned so far.
Programming a microcontroller
Building a Power supply
Wiring and creating a circuit
The Axiom TWR-S12G128 kit was one of the worst ones to use. I think that there could have been something more
affordable in the market where it would have been easier to learn how to code.