[LiChuang Development Board] Intelligent car based on Liangshan School

## Functional description

1. Motor control
2. Buzzer
3. ADC detection
4. Tracking
5. Mode switching
6. Bluetooth control
7. PWM speed regulation

## Schematic diagram design description

### 1. Power supply circuit
! [image.png] Two 18650 batteries are selected to power the car through the battery holder. After the HE6250 step-down chip, 5V voltage is output to power the microcontroller. The motor is directly connected to the 7.4V battery for power supply. It is equipped with a diode to prevent reverse connection and an LED power indicator.
### 2. Motor drive
! [image.png] Motor drive, choose RZ7899 chip. (After doing it, I found that it seems that less than 4 chips should be used. I feel sorry for my money).
### 3. LED and independent button circuit
! [image.png] One end of the LED and button is connected to the microcontroller pin. The high and low changes of the microcontroller level detect the button press and control the LED light on and off.
### 4. Buzzer circuit
![image.png] Use active buzzer, it will sound when powered on, cooperate with triode, and control the buzzer by adjusting the high and low levels of the IO port of the microcontroller.
### 5.ADC voltage acquisition circuit
![image.png] Measure ADC through the form of resistor voltage division.
### 6. Tracking circuit
![image.png] The tracking circuit is designed with LM393 voltage comparator and TCRT5000 infrared pair tube. Connect the 1 pin of the voltage comparator to the pin of the microcontroller, and judge whether the black line is detected by judging the high and low levels through the microcontroller.
### 7. Bluetooth module
![image.png] Use JDY-31 Bluetooth module, communicate with the microcontroller through the serial port, and control the forward and backward movement of the car.
### 8. Ultrasonic module
![image.png] Use the new HC-SR04, use the microcontroller pin to trigger the ultrasonic transmission, and calculate the distance between the car and the obstacle through the high level time returned by the timeout wave module.
### 9.2.4g module
![image.png] Using NRF24L01+ module (not yet implemented).
### 10. The wheels
use four N20 reduction motors, 6V 500 rpm.
## PCB design instructions

1. Pay attention to the line width of the power circuit, 7.4V 40mil, 5V 20mil
2. The layout of components should not only consider symmetry and beauty, but also convenient routing and physical size.

## Physical display instructions

The battery compartment is too tight, so it is all tilted
![DSC01222.JPG] It hurts my hand, so I took 3M glue and stuck it all on
![DSC01223.JPG] The poor Liangshan faction was used as a cushion
![DSC01224.JPG]
## Goal

1. Develop 2.4G remote control
2. Add a screen
3. Add WIFI module
4. Add a camera
## Video demonstration