Design of Solar Wireless Street Light Wireless Monitoring Energy Saving System

First. overview

Solar street light is a kind of street light that uses solar energy as an energy source. Because it has no influence on power supply, it does not need to ditch and embed the line, does not consume conventional electric energy, and can be installed on site if the sun is sufficient. Because it does not pollute the environment, it is called a green product. Solar street lights can be used for lighting of town parks, roads and lawns, but also for areas with small population density, inaccessible economy, lack of conventional fuel, and difficult to generate electricity with conventional energy, but solar energy resources are abundant to solve these areas. People's home lighting problems.

The solar light is an application product of photoelectric conversion technology, and has the advantages of energy saving, environmental protection, safety, no wiring, easy installation, automatic control, and the position of the insertion and replacement can be changed at any time as needed. The main types of solar lamps are solar garden lights, solar street lights, solar lawn lights, solar landscape lights, and solar signal lights.

In the practical application of solar street lamps, solar street lamps in many places cannot meet the normal lighting needs, especially in rainy days. Therefore, this requires solar street lamps to dynamically adjust their own power according to pedestrian conditions during work. At the same time, it can save more power and ensure long-term operation of the system. In addition, the existing solar street lamps can not detect and diagnose the faults of their own working state and peripheral circuit parameters, and cannot form a remote monitoring network, thus requiring a remote The wireless monitoring system detects the solar street lamp circuit parameters, and realizes the diagnosis and alarm functions for the faults that occur, and realizes the intelligent management of the street lights.

Second, the demand analysis

2.1 Functional requirements

1. The system is powered by solar cells and batteries, which is environmentally friendly and pollution-free;

2, solar cells can automatically track the sun, to maximize the use of solar energy;

3, the street lights can automatically light up when it is dark, and can be dynamic according to the situation of people passing by and no one passing by.

Adjust the power of the street lamp to achieve energy-saving effect; after 12 o'clock in the evening, due to the scarcity of pedestrians, the street lamp will be in a semi-activated state. When someone passes, it will light up. If no one passes, it will not light, and it will ensure the illumination of a small number of pedestrians. Energy saving; in the morning, enter the normal lighting mode again, until the daylight is off, enter the energy storage stage.

4. The system has an automatic monitoring function, which can monitor the operation of the street lamp and its peripheral circuits. Once an abnormal situation occurs, the slave sends it to the host through the wireless network. After the host is summarized, it is sent to the monitoring center via the GSM network to notify the technician to perform maintenance. To ensure the speed of maintenance.

2.2 Performance requirements

1, ADC conversion accuracy is 10 bits;

2. The effective distance of wireless transmission is 100m (different wireless modules can be used to realize long-distance transmission of data according to actual needs);

3, GSM super long transmission distance, as long as there is a signal, you can receive the data;

4. A monitoring center can monitor multiple hosts, and one host can monitor multiple slaves.

Third, the program design

3.1 System function realization principle

Figure 1: System block diagram

The system consists of three parts: the monitoring center, the main unit and the slave. The monitoring center realizes remote communication with the host through the GSM network. The host and the slave are close to each other, so the 2.4GHz wireless network is used for communication.

Figure 2: Block diagram of the hardware of the monitoring center

The monitoring center is mainly responsible for the analysis and display of the summary of each host. At the same time, it can notify the staff of the street lamp damage by means of on-site or texting. In addition, the system parameters can be set, mainly by AVR MCU, GSM module, light sensor, Human body infrared sensor module, matrix keyboard, sound and light alarm, position detection resistor, motor module, liquid crystal display, power management, real-time clock circuit DS1302, backup power supply, solar battery and battery.

Figure 3: Block diagram of the host hardware

The host is responsible for collecting the slave and its own monitoring data. It is the bridge between the monitoring center and the slave. It is mainly composed of AVR microcontroller, GSM module, wireless transmission module, optical sensor, human body infrared sensor module, position detection resistor, motor module, power management, Real-time clock circuit DS1302, backup power supply, solar battery and battery.

Figure 4: Slave hardware block diagram

The slave is responsible for controlling and processing the solar street light, and monitoring the circuit. If abnormal conditions are found, the fault diagnosis will be performed, and the result will be sent to the monitoring center through the host for processing. The AVR microcontroller, wireless transmission module, and optical sensor are mainly used. , human body infrared sensor module, position detection resistor, motor module, power management, real-time clock circuit DS1302, backup power supply, solar battery and battery.

3.2 Hardware platform selection and resource configuration

The hardware platform uses EVK1100, the serial port is used to communicate with the GSM module, the PWM is used for backlight conversion, the illumination sensor is used to detect ambient ambient light, the liquid crystal display is used to display various information, the SPI is used to communicate with the DS1302, and the ADC is used for solar cell voltage. Detection, battery voltage detection, ambient photometric detection, solar cell position detection and solar position detection, 1 universal input and output port for human body infrared detection module, 4 universal input and output ports for motor control, 8 universal input and output ports On the 4*4 matrix keyboard.

3.3 system software architecture

Figure 5: System Software Architecture

3.4 System Software Process

Figure 6: Flow chart of the monitoring center program

After the system is powered on, initialize the system and GSM module, then update the system time, and then judge whether it is day or not. If it is, continue to judge whether the system receives the information. If not, check if new information arrives. At night, there is The new information indicates that there is a problem with the host or the slave. The system enters the information processing stage. According to the user settings, there are two methods: local notification and SMS notification. If the user sets the notification as SMS, the system will only notify the user via SMS, but will not be local. Send an alarm to notify the user; then press the button to detect, press the button to enter the button processing program, set the system or view the status; then detect that no one is close, then open the LCD display and backlight, if not, turn them off; Then it is detected whether it is day or not.

During the day, the system checks whether there is information, and if there is information, it sends an alarm to notify the user and deletes the information; then detects the sun position and the solar cell voltage, if the solar cell voltage is lower than the set value, the flag is set; if the solar cell voltage is not The problem is that the system drives the motor to turn the solar battery to the maximum position of the sun. If the solar battery fails to reach the specified position within the specified time, it indicates that there is a problem with the steering system. Then, if there is any problem with the solar battery, if there is, the solar battery module is explained. There is a problem, if not, then the solar cell voltage is sampled again, compared with the last sampled voltage, the voltage difference is not large, indicating that the motor has a problem; the voltage difference between the two voltages is large, indicating that the position detection resistor has a problem, then The alarm informs the user that the program has completed a loop. When the front solar cell rotates and reaches the specified position, the system enters the timed loop state. If the system receives the host network access request, the host will perform network access processing; if no request is received, it will judge whether there is a button press, and then the system performs Button processing, no one detects no one is close, some open the LCD display and backlight, if not, turn them off; so cycle until the time is up.

Figure 7: Host program run flow chart

After the system is powered on, the system, the GSM module and the 2.4 GHz wireless module are initialized, and then the networking request is sent to the monitoring center until the response signal of the monitoring center is received, and the network is allowed to enter the network. Then, the monitoring center sends back a signal to update the system time, and then judges whether it is day or not. If yes, it determines whether the system has an error message. If not, it sends a message to query the slave state. At night, first send the inquiry information to the slave. If the slave response signal is not received within the specified time, the slave has a problem and the error flag is set. If the message is received, the system lights up and detects the battery voltage. If the battery voltage is less than the set value, the battery has a problem, the error flag is set; if the battery voltage is greater than the set value, it is judged whether the street light is on, the street light is not lit, the error flag is set; the street light is on, to determine whether there is an error. Bit, if any, wants the monitoring center to send an error code until it receives the response signal from the monitoring center, and then judges whether the host has an error. If yes, it enters standby mode and waits for maintenance. If not, it enters the streetlight working mode.

First, check if someone passes, and then adjust the power so that the street light is in the normal lighting mode. If it is not, then it is judged whether it is at 12 o'clock in the evening. If yes, the power adjustment is made to make the street lamp in the trigger working mode. Only when the person passes will be bright. light. If not, it is judged whether it is in the morning. If yes, the power adjustment is made to make the street lamp in the normal working mode. Otherwise, it is judged whether it is in the daytime. If it is in the daytime, the street lamp is extinguished and enters the daytime energy storage phase. If it has not arrived in the daytime, it is detected whether the time when no person passes the street lamp is greater than the predetermined value, then the power of the street lamp is adjusted to reduce the power consumption; if not, the passerby detection block is returned, and the cycle is repeated.

During the day, the system checks if there is an error message, and if not, the following procedure is not executed until the evening; if there is no error message, then the sun position and the solar cell voltage are detected, and if the solar cell voltage is lower than the set value, the flag position is set; There is no problem with the solar cell voltage. The system drives the motor to turn the solar cell to the maximum. If the solar cell fails to reach the specified position within the specified time, it indicates that there is a problem with the steering system. Then, if there is any problem with the solar cell, if there is, it indicates solar energy. There is a problem with the battery module. If not, the solar cell voltage is sampled again, and compared with the last sampled voltage. The voltage difference is not large, indicating that the motor has a problem; the voltage difference between the two is large, indicating the position detection resistor. There is a problem, then the alarm informs the user that the program has completed a loop. When the front solar cell rotates and reaches the designated position, the system enters the timed loop state. At this time, if the system receives the slave network request, the slave device is networked; this cycle until the timing time arrives.

Figure 8: Slave program run flow chart

The slave program running flowchart is similar to the host program running flowchart, and will not be repeated here.

3.5 System Expected Results

During the daytime, the solar street light is in an energy storage state, the control circuit detects the position of the sun through the light sensor, and controls the motor to rotate the solar battery to track the sun, so that it can obtain more solar energy and convert it into electric energy and store it in the battery; at night, the machine First, the self-test is performed, and the result is sent to the host through the wireless network. The host also performs self-test at the same time, and the result is collected and reported to the monitoring center through the GSM network. When the monitoring center finds the problem, the management personnel are notified to handle the problem; After the slave and the host enter the lighting mode, the human body infrared sensing module works. When someone passes, the street light enters the normal lighting mode; when no one passes for a while, the street light enters the energy-saving mode, and the luminous intensity decreases. At 12 o'clock in the evening, due to the scarcity of pedestrians during this period, the street light enters the trigger mode and only lights up when someone passes; in the morning, the street light enters the normal lighting mode again until dawn.

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