The LED plant light intelligent driver is divided into light supplement module, detection module, early warning module, control module and communication module (Figure 1)
Light supplement module: using constant current drive circuit, using Taiwan company's MBI6651 chip, the output current can be adjusted by external resistors of different resistance to adjust the current of each output stage, and the DIM pin is connected to pulse width modulation (PWM) Signal for dimming control. The pulse width determines the brightness, and the PWM technology is used to adjust the current by adjusting the duty cycle of the PWM signal, and finally adjust the brightness of the red and blue LED fill light.
Detection module: For the detection of red light and blue light, the light sensor is corrected by the way of fixed filter and sub-band filtering, so as to realize the measurement of the light factor intensity required by the plant in photosynthesis. For temperature detection, DS18B20 temperature sensor is used, which supports multi-point networking function and realizes multi-point temperature measurement.
Early warning module: This system is designed with an early warning module, which can automatically determine whether the LED smart lamp head group is working normally by calculating the range of illuminance changes in two adjacent times and comparing it with the PWM output. When it is judged that there is an abnormality, the single-chip microcomputer outputs an alarm signal, controls the buzzer to sound and the indicator light to light, and realizes the early warning function.
Control module: Using STC12C5A60S2 single-chip microcomputer as the core, the system is programmable, according to the threshold set by the user and the data collected by the monitoring module, the duty cycle of the corresponding PWM control signal is calculated, and after serial-to-parallel conversion through the MCU, the corresponding PWM control The signal is output through two parallel ports, which respectively control the red and blue constant current circuits in the fill light module, thereby changing the LED illuminance.
Communication module: A dedicated ZigBee transceiver chip is used. Here, Freescale’s MC13192 chip is selected, which conforms to the IEEE802.15.4 standard. Its operating frequency is 2.405-2.480GHz, and the data transmission rate is 250kbit/s. The communication chip and MCU pass SPI The interface is connected, and the work of the chip is controlled by the MCU.
The intelligent socket of LED plant light has detection function, communication function, control function and other functions (Figure 2)
(1) Energy metering module: Energy metering chip TM7755 is the core, and corresponding current and voltage sampling circuits are designed.
(2) Communication module: It is divided into a receiving part and a sending part. The receiving part can receive the current status of the intelligent LED plant growth light, and can also send commands to the LED light.
(3) Microprocessor: STR711FR2 microprocessor is adopted. It is embedded with 256+16 k Flash and 64 k RAM, and is responsible for the measurement, control, communication, and management of the entire system.
(4) Early warning module: when there is an abnormal situation in the socket, an alarm will be issued through the buzzer.
(5) Power module: This part converts the 220V AC voltage to AC-DC to provide working power for the system.
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