AlphaBot: Lane tracking with camera
| Autor: | Syed Muhammad Abis Rizvi |
| Art: | Praxissemester |
| Studiengang: | ELE |
| Starttermin: | 02.03.2026 |
| Abgabetermin: | 21.06.2026 |
| Betreuer: | Prof. Dr.-Ing. Schneider |
| Sprache: | DE EN |
Introduction
This is an Alphabot by waveshare which supports advanced navigation and sensing features. In this project our task is to drive the Alpha bot with in the right lane along the course by using a pixy2 camera and modify its speed limit. We also added a GY-85 gyroscope IMU sensor to record the Yaw rate so that we can later calculate the yaw angle from the yaw rate data, later we plan to add a Bluetooth module to get the data wirelessly.These components works together so that Alpha bot can drive independently in real time.
Requirements
| Req. | Description | Priority |
|---|---|---|
| 1 | An AMR must drive autonomously in the right-hand lane. | 1 |
| 2 | The Topcon Robotic Total Station is used as the reference measurement system. | 1 |
| 3 | The AMR must evaluate the road data via camera (Pixy 2.1) to follow the lane. | 2 |
| 4 | The reference values must be recorded with MATLAB (x, y, ). | 1 |
| 5 | Measurement errors must be appropriately filtered. | 1 |
| 6 | The two-dimensional digital map showing the robot's pose during movement must be provided as a MATLAB® file (.mat). | 1 |
| 7 | The solution path and solution must be documented in this wiki article. | 1 |
| 8 | An AlphaBot must be used as the AMR. | 1 |
| 9 | MATLAB®/Simulink must be used as the control software. | 1 |
| 10 | From the measured yaw rate the yaw angle must be determined and compared to the reference from Req. 4. | 1 |
| 11 | The AlphaBot's speed must be optimized to it's maximum. | 1 |
Working principle
The AlphaBot uses the Pixy" camera to detect the lane which helps Alphabot to poistion itself on the track and based on this infromation the motor runs and the Alphabot runs independently on the track and stop immediately when it does not detect any line.
GY-85 IMU sensor measures the yaw rate, which is used to detemine the AlphaBot's (yaw angle) according to its movements.
All componennts work together in real time to make sure the AlphaBot runs independently in real time.
Technical Overview
The system is built on the waveshare AphaBot which is integrated with motors. A pixy2 camera is used for keeping the AlphaBot on track.
Gy-85 IMU used to record yaw rate and yaw angle.
Bluetooth module is used for collecting the output wirelessly in real time.
Pin Assignment
The following pin configuration is used to interface the sensors and control the AlphaBot:
Pixy2 Camera (SPI/UART Interface)
Pixy2 Camera is connected to the controller using I2C:
SDA : A4
SCL : A5
VCC : 5V
GND : GND
GY-85 IMU Sensor (I2C Interface)
GY-85 IMU Sensor communicates via I2C:
SDA : A4 (shared I2C bus)
SCL : A5 (shared I2C bus)
VCC : 3.3V / 5V
GND : GND
Serial / Bluetooth
TX (Bluetooth) : RX (D0)
RX (Bluetooth) : TX (D1)
VCC : 5V / 3.3V
GND : GND
Both Pixy2 and GY-85 share the same I2C lines.
Motor Driver (on AlphaBot)
The motors are controlled via PWM pins from the controller:
Left Motor
PWMA : D6 (PWM)
AIN1 : A1
AIN2 : A0
Right Motor
PWMB : D5 (PWM)
BIN1 : A2
BIN2 : A3
Power Supply Battery : AlphaBot power input and sensors powered via onboard voltage regulator.
Measurement method
Measurement is done by using onboard sensors on AlphaBot. Pixy2 camera detects the lane position from which lateral error is calculated. The GY-85 IMU sensor measures the yaw rate which helps determine the yaw angle.
Formula for yaw angle.
\[ \theta(t) = \theta_0 + \int_{0}^{t} \omega(t)\, dt \]
\[ \theta_k = \theta_{k-1} + \omega_k \cdot \Delta t \]
Measuring Circuit
The measuring circuit consists of the AlphaBot and the GY-85 IMU Sensor for recording yaw rate and yaw angle.
Software
PixyMonV2 is used to teach Pixy2 camera to specifiy lane tracking and enhance its vision settings using color-based filtering.
AlphaBot is coded in Ardunio C/C++.
Arduino IDE
The AlphaBot's software is created with the Arduino IDE, which offers a unified environment for writing, compiling, and uploading code to the microcontroller.
The program utilizes Arduino C/C++ and incorporates standard libraries like Wire.h for I2C communication and Pixy2I2C.h for the Pixy2 camera. The loop function operates continuously to read the sensors, compute the yaw rate and yaw angle, and manage the motors.
The Serial Monitor allows for the viewing o data in real-time (line error, yaw rate, heading, motor speeds). This data can also be monitored via Bluetooth for wirelessly.
Simulink
The AlphaBot’s behavior can be modeled, simulated, and analyzed using Simulink, a visual programming environment based on MATLAB.
Measurement
The measurement system records the robot’s navigation performance using onboard sensor.
The Pixy2 Camera for lane detection measurement.
The GY-85 IMU Sensor for measuring yaw rate and yaw angle.
Video
Datasheets
| Component | Model / Type | Key Specifications | Function in Project |
|---|---|---|---|
| AlphaBot | Waveshare AlphaBot | 2 DC motors, motor driver, chassis, 6–12V power input | Mobile platform for autonomous navigation |
| Pixy2 Camera | Pixy2 CMUcam5 | 60 fps
I2C/SPI/UART interface Line-tracking mode || Lane detection and position measurement | |
| GY-85 IMU | GY-85 (HMC5883L + MPU6050) | 3-axis gyroscope, accelerometer, magnetometer
I2C interface || Measures yaw rate, heading, and motion data | |
| Bluetooth Module | HC-05 / HC-06 | UART interface, 3.3–5V operation, 10 m range | Wireless telemetry of sensor and motor data |
| Controller | Arduino Uno / compatible | 16 MHz, 5V logic, 32 KB flash | Reads sensors, computes control, drives motors |
| Motors | DC motors on AlphaBot | 6–12V, PWM control | Propulsion and steering |
| Power Supply | Li-ion / Battery pack | 7.4–12V typical | Powers motors, sensors, and controller |
Related Links
SVN-Repository
https://svn.hshl.de/svn/HSHL_Projekte/trunk/AlphaBot
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