Week 17: System Integeration

Objectives of the Week

Implemented Methods of Packaging?

Designed your final project to look lik a Finished Product

Docmented System Integeration of your Final Project

Linked to your System Integeration documentation from your Final Project

For More about Final Project

System Integration

So, when we talk about system integration, we're basically referring to the process of combining all the different parts of a system—things like sensors, controllers, actuators, displays—into one complete setup that works together smoothly. It’s not just about connecting wires or writing code for each part, but making sure they all communicate properly, both in terms of hardware and software.

In robotics or product development, this means aligning everything—electronics, the mechanical build, power supply, and programming logic—so the entire system behaves the way we want it to. If it's done right, system integration helps reduce complexity, improves how the robot performs, and makes it much easier to control and troubleshoot. The goal is to make sure the whole system meets functional needs, runs safely, and is easy to use.

About My Final Project - Line Bot

Overview

For my final project at Fab Academy, I built a robot called the Line Bot, which is an autonomous line-following mobile robot. The idea is simple but powerful—the robot can detect and follow a path marked on the ground using infrared sensors.

Main Components

XIAO ESP32-C3 – Main microcontroller handling logic and control
Custom Motor + Sensor Interface PCB – Designed and fabricated for organized integration
BO Motors with Plastic Wheels – Used for smooth movement
L298N Motor Driver – Dual H-Bridge module to control motor direction and speed
5-Line IR Sensor Array – Detects the line on the floor
OLED Display – Shows live feedback like sensor data or direction
Acrylic Chassis – Laser-cut sheet that holds the components
JST Connectors – For neat and reliable wiring
Li-ion Battery – To power the complete system
Line Marker Tape – Used to lay the black path on white surface

Working Principle

The 5-line IR sensor array reads the contrast between the black line and white background. Based on this input, the ESP32-C3 calculates motor speed adjustments using PWM signals. The L298N driver then controls the left and right BO motors accordingly to follow the line precisely.

The OLED display provides real-time information, helping during testing and debugging. All wiring is routed through JST connectors to maintain reliability and reduce loose connections.

System Testing

The system was tested under various lighting and surface conditions to verify sensor accuracy and motor control. Integration was carefully checked to ensure all modules—from sensors to motors—communicate and perform in sync. The final robot delivers stable, smooth, and accurate line-following performance.

Line Follower Bot - Bill of Materials

S. No	Component	Description	Qty	Unit Price (USD)	Total Price (USD)
1	XIAO ESP32-C3	Microcontroller Unit	1	5.50	5.50
2	Fabricated PCBs	Custom Motor + Sensor Interface	2	2.00	4.00
3	Header Pins & Wires	Male/Female Headers, Solder Wires	1 set	1.00	1.00
4	BO Motors + Wheels	Plastic Gear Motors with Wheels	2 sets	2.50	5.00
5	L298N Motor Driver	Dual H-Bridge Driver Module	2	2.00	4.00
6	Connector Wires + JST	JST 2/7-pin wires & terminals	2 sets	1.00	2.00
7	OLED Display	0.96" I2C Monochrome	1	3.00	3.00
8	5-Line Sensor Array	IR Line Detection Module	1	4.00	4.00
9	Acrylic Sheet	100x100 mm Chassis Base	1	1.50	1.50
10	Line Marker Tape	Black Tape for Path	1 roll	0.50	0.50
Total Cost					$30.50

Line Follower Bot Gantt Chart

Subsystem 1: Mechanical Design and Fabrication

Task	Week 1	Week 2	Week 3	Week 4
Rough Sketch
CAD Modelling
Component Selection
3D Printing
Assembly & Fitting

Subsystem 2: On-Bot PCB Design

Task	Week 1	Week 2	Week 3	Week 4
Schematic Design
Power Calculation
PCB Layout
Fabrication & Testing

Subsystem 3: Sensor + Line Following Logic

Task	Week 1	Week 2	Week 3	Week 4
IR Sensor Calibration
Threshold Tuning
Tracking Algorithm

Subsystem 4: Bot Control Software

Task	Week 1	Week 2	Week 3	Week 4
PWM + PID Setup
Motor Control Logic
Serial Debug + Logs

Subsystem 5: Testing and Final Tuning

Task	Week 1	Week 2	Week 3	Week 4
Integration Test
Performance Test
Final Field Run

4. Component Overview

Microcontroller: XIAO ESP32-C3 - Compact, low-power board with built-in Wi-Fi and Bluetooth. Responsible for all sensor processing and motor control.
Motor Drivers: L298N Dual H-Bridge Motor Driver - Controls two BO motors independently through PWM.
Sensors: 5-Channel Infrared Sensor Array - Used to detect the contrast between black line and white background. Analog or digital values processed by ESP32.
Display: 0.96" OLED I2C Display - Displays real-time sensor readings, motor status, and debug messages.
Power System: Li-ion battery (3.7V) with boost converter to 5V/7.4V output.
Mechanical: Acrylic Base (laser-cut), BO motors with wheels, mounting hardware, and wiring using JST connectors.

5. Electronics Architecture

The electronics design was tailored for simplicity and efficiency. The ESP32-C3 interfaces with:

IR sensor via analog/digital input pins.
L298N motor driver via PWM-enabled GPIOs.
OLED via I2C communication (SCL, SDA).
Power supplied from a Li-ion battery regulated via onboard voltage converters.

The system wiring was planned carefully to ensure minimal noise, secure connections, and clear power/data paths. The use of JST connectors simplified replacements and debugging.

6. Mechanical Structure

The body of the robot was designed in CAD and laser cut using 3mm acrylic sheet. The design considerations included:

Adequate spacing between wheels and sensors.
Firm placement of motor driver and MCU.
Slots for wiring and connectors.
Mounting holes for sensors to face the ground at a proper angle.

3D Design

Laser Cutting Process

The BO motors were mounted using acrylic brackets, and the IR sensor array was placed at the front underside. The final structure ensured good balance, durability, and access for debugging.