Design of smart Bluetooth car based on Liangshan School

1. Project Introduction
The car is based on the Liangshanpai development board and can switch between two modes. It is equipped with an HC05 Bluetooth module and can be remotely controlled by a Bluetooth app. It has five infrared automatic tracking channels and an ultrasonic obstacle avoidance function. The passive buzzer can sound an alarm when encountering obstacles.
General Function Introduction
1. LED lights:
There are two LED lights in front of the car, one on each side.
2. Buttons:
The car expansion board has two independent buttons, KEYS and KEYM, which are used to start and switch between sports modes. The KEYS button has a green LEDS indicator, and the KEYM button has a blue LEDM indicator. Pressing the button can switch the status of the light.
3. Buzzer:
    The car is equipped with a buzzer, which can be used to sound an alarm when encountering obstacles.
4. ADC voltage detection:
The car is equipped with an ADC voltage detection circuit, which uses the ADC acquisition function to realize voltage acquisition. When the battery is out of power, the buzzer sounds to remind us to charge in time.
5. Ultrasonic module:
There is an HCSR04 ultrasonic module in front of the car, which can be used to achieve ultrasonic obstacle avoidance.
6. Motor:
The car has four motors, driven by RZ7899 chip. It can realize forward, backward, left turn, right turn, stop (brake/turn off), and the speed of the car can be changed by combining the timer PWM function.
7. Tracking:
The car is equipped with 5 infrared tracking channels, which can be used to follow the black line.
8. Obstacle avoidance:
The car can use the ultrasonic module to complete the obstacle avoidance function.
9. Bluetooth module:
The car provides a Bluetooth module interface, which can be used with the mobile phone Bluetooth APP to realize the function of wireless remote control of the car.
10. Camera
The car has reserved the camera module interface circuit.
11. 2.4G wireless module
    The car has reserved the 2.4G wireless module interface circuit.
Physical picture:
 
Overall design scheme Circuit design The
 
input interface of the power supply is a battery holder connected to 2 3.7V 14500 lithium batteries to power the car. The power supply passes through a HE6250MPR step-down chip to output a fixed 5V voltage to provide power to the microcontroller and peripheral devices, and the motor driver chip is directly powered by the battery.
The motor drive circuit
 
RZ7899 is a DC bidirectional motor drive circuit with good anti-interference, small standby current and low output internal resistance. It controls the forward, backward and braking of the motor through two logic input terminals BI and FI. BI and FI are connected to the microcontroller IO. By changing the high and low levels of the microcontroller I/O port output, the level of the chip control end output pin is changed, so as to control the forward and reverse rotation, stop and brake of the motor. It is very convenient to use and can meet the high current requirements of DC motors. The working principle of
 
the tracking circuit
 
 
is to connect the pin of the voltage comparator to the pin of the microcontroller, and the IO is configured as the input mode. When the pin of the voltage comparator outputs a high level, it means that the infrared light is absorbed, the black line is detected, the LED indicator lights up, and the microcontroller IO reads a high level. The principle of infrared tracking: using infrared light to avoid
obstacles in different colors . The circuit uses the HC-SR04 module and ultrasonic module to achieve the obstacle avoidance function. PS: Tracking demonstration video. Due to the current conditions, black ribbon is used for demonstration. Please forgive me (*^_^*) Project summary.    Through the study of this project, I have roughly mastered the basic hardware circuit design ability, strengthened and consolidated the schematic diagram and PCB drawing ability, and improved the software code function debugging ability to a certain extent, as well as the ability to solve various problems encountered in the project development process. It is a good experience. Thank you for the support of LiChuang! ! !