Liangshan faction car

## **Question requirements**
1. Based on Liangshanpai development board
2. Self-designed-originality


## **Description of car board functions**
1. Ultrasonic ranging module-obstacle avoidance car
2. Infrared module-tracking car
3. Status indicator-car status indication
4. Buzzer-car status indication 5.
2.4G module-remote control
6. Bluetooth module-remote control



## **Schematic design description** ### 1. The power chip selects Infineon's TLE42754D. This LDO is a car-grade LDO with a wide temperature tolerance range and good stability. It can continuously output 450mA current, package TO252-4, generate little heat, and dissipate heat quickly. ![1.png]
### 2. The power plug uses a T-shaped plug, which can withstand a maximum current of **30A. It has the function of anti-reverse connection**. The figure below shows the plug at the battery end, and the board is its opposite end. The connection is stable and reliable to avoid power failure due to the bumps of the car. ![2.png] ### 3. OLED uses a 0.96-inch OLED display screen to **display the parameters of the car** and output debugging information during debugging, which is convenient for debugging and understanding the status of the car. ![3.png] ### 4. Buzzer circuit The buzzer is driven by **NPN transistor. When the level is high, the buzzer sounds, and when the level is low, the buzzer does not sound**. This design can avoid the abnormal buzzer sound caused by the unstable pin level when the car is powered on. ![4.png] ### 5. Button circuit The button is valid at low level, and the external **capacitor is used for hardware debouncing**. ![5.png] ### 6. Remote control circuit The remote control part uses: 2.4G NRF24L01 module ![6.png] ### 7. Motor drive circuit The motor drive chip uses RZ7899 chip, which can drive a motor. At the motor output end, **a 104 capacitor is connected in parallel** to eliminate the back electromotive force and even sparks when the motor is commutated or stopped. ![7.png] ### 8. The tracking circuit op amp chip uses LM393, and the infrared pair tube uses ITR9909. The sensitivity of the infrared module can be adjusted by adjusting the organization of the RP1 resistor. ![8.png] ## **PCB design instructions** The Liangshan School development board is placed on the front of the board, and the sliding rheostat of the tracking part is placed on the front of the board for easy adjustment. The circuit of the tracking module is placed on the bottom of the board. The main power switch is placed on the edge of the board for easy switching. Liangshan School's socket welding method uses the main chip facing up, which is convenient for pressing the reset button. ![9.png] ![10.png] The layout of the power supply part, as long as the line is short and thick, can stably output the required voltage and current. ![11.png] ## **3D diagram as shown** ![12.png] ## **Battery charging method** The battery is charged with a B3 balance charger, which can ensure **balanced power between the two batteries**. ![20.png] Battery charging diagram: ![21.png] ## **Software description** //OLED function 1. Display the distance of the ultrasonic wave; 2. Display the real-time voltage of the battery; 3. Display the remaining parameter information of the car; 4. Display personalized information; example: ![22.png] ## **Physical display description** ![13.png] On this side, you can see the OLED, power supply part, and Liangshan School development board. ![14.png] On this side, you can see the ultrasonic module and tracking module adjustment potentiometer. ![16.png] Here is the battery, using **two 603040 polymer lithium batteries in series** to power the entire system. And stick it to the bottom plate. Battery charging port, placed next to the battery. ![23.png] Turn on the switch and power on the car! ! ## **Demo video** B station link: https://www.bilibili.com/video/BV17s4y1F7XQ ## **Other development plans** 1. The 2.4G module based on Liangshan School has been drawn, but not verified yet. Wait for the next free board, and then verify and open source. Function: gravity sensing, 2.4G remote control, display, joystick, buttons, indicator lights, lithium battery power supply, rechargeable, free proofing effect diagram is as follows: ![26.png] ![27.png] 2. Enrich the car functions; such as: gravity sensing remote control, ultrasonic drawing site scanning map, etc. ## **Other attachments uploaded** 1. Program for ultrasonic ranging to display on OLED. 2. Program for car movement. 3. Some chip datasheets. ## **Acknowledgements** Thank you very much for the strong support of LiChuang development board! And the guidance of LiChuang engineers!