The Design Research Of Control System Of Electromagnetic Braille Display Device

Across the globe, there are about 285 million people with varying degrees of vision damage,among which, the number of the blind people whose vision are serious damaged is approximately 39 million, about 13.68% of the total number of visual impairment. The number of the blind in China as the most populous country is the largest in the world, which has about8.25 million people that accounting for 21% of the total number of blind people worldwide[1].Electromagnetic braille display device is an effective way that the blind use tactile perception to obtain external information, which are demanded more and more and becoming more popular in research labs.This paper, based on the mechanical body of the electromagnetic braille display device which is independent R&D work as the main body, analyzes the present situation and the development tendency of the domestic and foreign electromagnetic braille display device,designs and implements the system of the braille drive and the blind text display of the electromagnetic braille display device, at last, tests the overall performance of the electromagnetic braille display device.Firstly, based on the mechanical structure of the electromagnetic braille display device, this paper carries out the R&D work of the control system of electromagnetic braille display device based on the MCS-51 single-chip computer. The control system consists of power module, main control module, control circuit module, amplifier module and display module. The work includes using the Protues software for the simulation of the circuit and the Altium Designer software for the design of circuit board. Utilizing the Keil software to write the control program, drives the electromagnetic coil to control the braille display device to display the braille characters.Secondly, on the basis of the original functions, this paper organizes and improves the program, which is ported to the higher level of SCM with Cortex-M3 as the kernel, adds the braille display device of braille characters LCD display module, the SD file management module,to further improve the function of the drive control system of the braille display device. The circuit board of the control system of the electromagnetic braille display device has achieved its optimal design, the 2 layer PCB board is changed into 4 layers of PCB boards, at the same time,the DIP packages are replaced by the SMD packages, which greatly reduces the size of the circuit board.In order to verify the effectiveness of the system of the braille characters display and the electromagnetic Braille display device driver, this paper carries out force sensing experiment,braille characters display perception experiment of the electromagnetic braille display device.The results of experiments show that, when the electromagnetic coil of braille driven of the electromagnetic braille display device is supplied by 6V power supply voltage, the electromagnetic coil can output enough force to drive the braille point, the finger has good feel in the process of perception in Braille.Finally, we summarized the full text and speculated future work of the electromagnetic braille display device.