Design of an Intelligent Control System for Vehicle Headlights Based on Microcontroller
Ren Wei
(Nanyang Institute of Technology)
【Abstract】With the development of new energy, the number of household vehicles continues to increase, leading to frequent traffic accidents. Among these, a significant proportion of accidents at night are due to lighting issues. To reduce the occurrence of nighttime traffic accidents, alleviate driver stress, and enhance user experience, the intelligent control of vehicle headlights has become an important challenge. This paper designs an intelligent control system for vehicle headlights based on a microcontroller. Through circuit hardware design, software programming design, and simulation verification, this system can adaptively control the switching on and off of lights and the switching between high and low beams based on complex road and lighting conditions. Additionally, the system features filtering capabilities, strong anti-interference ability, and simple installation, making it suitable for most vehicle models.
【Keywords】Microcontroller; Intelligent Headlights; Control System
0 Introduction
In recent years, the rapid development of new energy vehicles has significantly increased the per capita ownership of cars. While the widespread use of vehicles has made life more convenient, it has also led to frequent traffic accidents, resulting in loss of life and property. A considerable number of nighttime traffic accidents are caused by inexperienced drivers, failure to turn on headlights, or incorrect use of high and low beams. Currently, although the lighting function of headlights has seen significant technological upgrades, there are still drawbacks, such as the inability to perform real-time, adaptive switching between high and low beams. To meet the demand for intelligent living, the intelligent control of headlights has become an inevitable trend for future development. This paper designs an intelligent control system for vehicle headlights based on a microcontroller, with the microcontroller serving as the core CPU responsible for overall sensor data acquisition and control command transmission. The design of the entire system includes hardware circuit design, software programming design, and simulation verification. The system can adaptively turn on or off headlights and adjust the state of high and low beams based on complex road environments and lighting conditions, thereby reducing driver stress. The system is highly reliable and has significant practical implications.
1 Intelligent Control System Hardware Design
1.1 Overall Design of the Control System
The implementation of intelligent control for vehicle headlights primarily requires real-time monitoring of the surrounding environment during vehicle operation, data processing and command transmission by the main control chip, and the driving execution function of the actuator components. Therefore, the proposed intelligent control system for headlights mainly consists of a monitoring module, a main control module, and an execution module. The overall block diagram design of the intelligent control system is shown in Figure 1. Due to the advantages of high control precision, low cost, and user-friendly operation of microcontrollers, the STC89C51 microcontroller is selected as the main control chip to effectively reduce the overall cost of the vehicle.
1.2 Module Circuit Design of the Control System
1.2.1 Circuit Design of STC89C51
According to the overall design of the control system, the control module uses the STC89C51 microcontroller. Considering the control requirements for vehicle headlights, the module circuit needs to include a clock circuit and a reset circuit to ensure that the microcontroller’s port values can automatically reset. The circuit diagram of the microcontroller design after adding the clock and reset circuits is shown in Figure 2.
Since this intelligent control system requires timing operations, capacitors are connected to pins 18 and 19 (XTAL1, XTAL2) of the STC89C51 microcontroller, along with a quartz crystal oscillator to form an oscillation loop, thus completing the timer function. The reset function requires a positive pulse to be applied to pin 9 of the STC89C51 microcontroller. Therefore, one end of capacitor C1 is connected to the VCC power supply, while the other end is connected to resistor R1 and in parallel with button RST1. In addition to the automatic reset function achieved through capacitor charging, manually pressing button RST1 can also achieve a reset, thereby clearing the state when the STC89C51 receives or sends erroneous commands and performing port initialization settings.
1.2.2 Circuit Design of Monitoring Module ADC0832
The core of precision control in the intelligent control system for headlights lies in the monitoring module. To monitor the surrounding environmental light, the rate of change in light intensity, and the distance data of oncoming vehicles during encounters, various sensors need to be used in combination. Based on the analysis and research of application scenarios, the BH1750 integrated light sensor is selected to monitor environmental light intensity and the rate of change in light intensity, transmitting the monitoring information to the microcontroller.[4].
The pin circuit diagram of the ADC0832 is shown in Figure 3. In Figure 3, a filtering circuit is also added, using capacitive filtering to reduce noise. Capacitor C4 is connected to pin 3 of the ADC0832. Since the discharge speed of the capacitor determines the effectiveness of noise filtering, C4 is selected as a 100nF capacitor.
1.3 Overall PCB Design of the Control System
Based on the circuit design of the intelligent control system for headlights in Section 1.2, the device layout, PCB design, and physical soldering have been completed. The overall PCB design of the intelligent control system for headlights is shown in Figure 4.
For intelligent control systems, the sensitivity and precision of sensors are core to control accuracy. The control system proposed in this paper involves various sensors, which have poor high-temperature resistance, making the soldering of the PCB a certain challenge.[5].
2 Software Design of the Intelligent Control System for Headlights
2.1 Main Program Programming Design of the Control System
The software programming part of the intelligent control system for headlights is mainly implemented using Keil5 software. The main program first initializes each control port, then the sensors begin to work in real-time and transmit data in real-time, sending environmental information to the microcontroller via the ADC0832. The microcontroller makes programming decisions based on the received data to determine whether to turn on the headlights and whether to perform adaptive state changes between high and low beams. The overall programming idea is shown in Figure 5. Based on this programming idea, the corresponding program has been written, and relevant functions have been customized; specific details are not elaborated here.
2.2 Program Design of the Monitoring Part of the Control System
The sensor data from the monitoring part needs to be exchanged between the microcontroller and the sensors through the analog-to-digital converter ADC0832. The ADC0832 uses a serial data transmission protocol, employing two buses for data transmission: the clock bus and the data bus.[6].
When the sensor detects environmental data, it transmits it to the ADC0832. The ADC0832 performs analog-to-digital conversion and reads the data. It checks whether the end bit of the data conversion is 1. If this bit is 1, it indicates that the data conversion has been completed, and the program subsequently ends.
2.3 Program Design of the Actuator for Headlights in the Control System
The actuator part of the intelligent control system for headlights mainly controls the state of the headlights to meet environmental requirements and user habits. Therefore, during the design process, two control modes were specifically designed: automatic mode and manual mode. At the start of the program, the user’s mode selection is first detected.
In manual mode, the user can achieve corresponding functions by pressing the relevant headlight control buttons, and the microcontroller will scan the status of the relevant headlight buttons in real-time to ensure that the user’s needs can be responded to immediately.
In automatic mode, the microcontroller will adaptively decide whether to turn on the low beam, whether to turn on the high beam, and whether to turn off all headlights based on the collected environmental information. The design idea of the actuator headlight program in the control system is shown in Figure 6.
3 Conclusion
The proper use of vehicle headlights is an important guarantee for nighttime driving safety. When encountering oncoming traffic, the glare from high beams can cause visual impairment for drivers, leading to traffic accidents. However, the varying road conditions, environmental factors, and drivers’ familiarity with the roads make existing vehicle headlight systems unable to meet the growing demands of the public, posing significant safety risks. Therefore, this paper proposes an intelligent control system for vehicle headlights based on a microcontroller. This system is a novel, intelligent, and modular solution that achieves adaptive control of vehicle headlights through hardware circuit design and software programming design.
The simulation verification results conducted using Proteus software indicate that this system can adaptively change the state of the headlights in real-time based on external environmental conditions and provides both manual and automatic control modes to meet different user needs. This design not only maximally satisfies contemporary user requirements and reduces the burden on drivers but also enhances driving safety. Furthermore, the system has a high cost-performance ratio and reliability, making it suitable for most vehicle models, with very convenient installation and use, thus possessing broad promotional application value.
References
[1] Li Su, Chen Lei, Guo Rencheng, et al. Intelligent Control System for Simulated Vehicle External Headlights [J]. Science and Technology Innovation, 2025 (3): 58-61.
[2] Tang Nana. Design and Research of Intelligent Control for Vehicle Headlights Based on Microcontroller [J]. Electronic Production, 2024, 32 (16): 100-102, 99.
[3] He Pei. Design of Intelligent Control System for Traffic Lights Based on Microcontroller [J]. Electronic Technology, 2024, 53 (7): 13-15.
[4] Gao Shuzhi, Li Tianchi. Design of Intelligent Control System for Classroom Lighting Based on Microcontroller [J]. Control Engineering, 2020, 27 (11): 2010-2015.
[5] Liu Yuzhong. Research on Intelligent Control Methods for Automotive Wipers and Lights Based on Embedded Technology [D]. Xi’an: Xi’an University of Technology, 2017.
[6] Cao Min, Ding Kun, Xiao Wenxiu. Design and Experiment of Intelligent Control System for External Headlights [J]. Journal of Shanghai Jiao Tong University, 2008 (4): 548-553.
Excerpt from “Automotive Electronics” 2025, Issue 9, pp. 121-123
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