Development Of Rotary Led Advertising Screen Based On Microcomputer Unit

A one square meters LED electronic advertising screen needs a larger number ofsemiconductor light-emitting diode pixels, to this relatively high cost phenomenon, we designa rotary LED advertising screen based on Microcomputer Unit. The advertising screen adoptsdynamic column-by-column scanning method and makes use of the human eye’s persistenceof vision characteristics. Then two light-emitting diodes rotate in a certain speed under thefunction of DC motor to show the whole picture. our advertising screen is cheaper thansimilar market products. This paper consists the system hardware circuit design, softwaredesign, anti-jamming design and system testing four parts.The hardware circuit design utilizes a SPI, PWM, UART, timer counter and otherfunctional module integrated in Microcomputer Unit. It gives out the power transmission lines,advertising screen mechanical structure, voltage conversion circuit, the DC motor drivecontrol circuit which is used to rotate the display, the wireless receiver module PCR1Aperipheral circuits which is used to control screen switching, display driver circuit, theexternal expansion data memory circuits of1M bytes and serial communication circuit.System software design components include a remote control radio frequencytransmission signal decoding program. It makes use of SPI interface program to read datafrom the serial data memory quickly, after reading the data, stores the data into themicroprocessor memory. Then, microprocessor sends data to the display drive program whichis used to drive the display screen of the shift register SN74HC595. The system softwaredesign also realizes information update of the data stored in memory PMLV080B. It adjuststhe PWM DC motor speed control program in the way of pulse width modulation, so that therotation speed reaches optimal rotation speed value of the display screen effect inexperimental conditions, and the actual speed is detected in real-time. To make sure that therotation speed is stable and the display screen effect is the best, we adjust the motor speeddynamically by closed-loop control when. Anti-jamming design mainly introduces the anti-jamming measures taken in the powercircuit design, wireless transmission and the printed circuit board process.System testing mainly tests every sub-module of system respectively, such as thewireless signal reception test, serial communications test, data memory read and writetests,the display driver test and the whole test. We constantly improve the system scheme bytest experiment, and ensure the feasibility and stability of the scheme. Through the whole test,we test the compatibility of each module, which provides a basis for further improvements ofthe system.Through testing of indoor and outdoor environments, the system has reached the desiredfunctionality. The product has a broad application prospect.