Three-in-one expansion board with infrared tracking module, impact detection, and ultrasonic obstacle avoidance.

Key Improvements:
The eight-channel infrared tracking light is fully lit upon power-up, but turns off when the tracking sensor detects a black line. This differs from other products on the market. My suggestion is to change it so that the light illuminates when a black line is detected and turns off when detected. This is a hardware bug; please be aware of this if you adopt this project.
The potentiometer for adjusting the infrared light could be a rotary type, but it's more expensive; consider the application requirements.
Project Introduction:
This project was prepared for an electronics design competition last year, but unfortunately, there was no car-related topic. However, it was later used in other projects.
This is a multi-functional sensor expansion board with ultrasonic obstacle avoidance, infrared tracking, and impact detection. All pins are brought out, and it uses a 5V power supply.
Project Functions:

An eight-channel infrared tracking sensor, symmetrically designed for easy detection of black lines, is used for tracking
. An HC-SR04 ultrasonic interface can be plugged in to measure distance. This allows the car to follow people or avoid obstacles.
Impact detection can be used for limit functions; of course, I'm thinking of impact detection, but it could also be used for other functions.

Physical Demonstration
Notes
: 1. When soldering, please pay attention to the soldering order to ensure the power supply is correct and to avoid burning out subsequent circuits! The soldering order should follow the principle of from shortest to smallest, and from inside to outside.
2. The circuit has been verified. Solder according to the component parameters in the schematic diagram. It is recommended to solder the main controller first, as it is more difficult to solder. It is recommended to use a heated soldering station
. 3. When using board cleaning fluid, be careful not to let it come into contact with plastic, as some plastic materials will cause minor problems after corrosion.
4. It is recommended to use the schematic diagram parameters. The BOM list contains errors.
Acknowledgements:
Thank you for your patience in reading. Due to my limited technical level, if there are any omissions or errors, please feel free to provide valuable feedback.