A FPGA-Based Laser Pointer Instruction-Aid System

Based on various kinds of existing equipment and technology research achievements in E-Learning Lab of SJTU, this paper tries to continue to study a laser pointer instruction-aid system. In this paper, a FPGA-based laser pointer instruction-aid system is designed and used in practice in teaching. It focuses on the teacher and is based on the"blackboard"in the classroom. A laser pointer is used to realize the indication and operation on the screen at a distance from the display screen to provide a freer teaching and learning scene.Based on the original laser pointer system, light spots recognition algorithm is replanted in FPGA to reduce the computational burden of the host and also the camera is embedded in FPGA to decrease the number of devices. The principle of the FPGA-Based laser pointer instruction-aid system is as follow:Based on the commonly used OV9650 camera module and 315MHz wireless transceiver module, a design of interactive system with FPGA to implement the interaction between a laser pointer with the projection display on a large screen was adopted. The digital signal obtained by the OV9650 camera module and the wireless signal received by the 315MHz wireless receiver module is processed and cached by FPGA. Then FPGA figures out the coordinates of the laser spot and sends the coordinates and the received wireless signal to the computer. The software on the computer processes the information to realize the interaction between the laser pointer and the projection display on a large screen.The hardware part of the laser pointer system is made by ourselves and is made up of the laser pointer transmitter and the reception controller. The laser pointer transmitter is a handheld device, each functional buttons and the laser head are set in the places where the presenter is easy to operate. There are wireless transmission function and laser pointer indication function of the laser pointer. The laser head gives out the laser spot which is used to indicate highlights of the screen and the wireless transmission is applied to control the slideshow at a distance from the computer. The reception controller is a device which center on FPGA and is made up of host processor module (FPGA), camera capture module, wireless reception module, VGA interface module, memory module, serial port convert USB port module and power module. The USB port of the reception controller is used to connect the USB port of the host to deliver the laser spot coordinate which is calculated by the FPGA chip and the control information which is received by the wireless reception module. Then, the information is processed by the host to realize the interaction function of the slideshow.According to the design of the entire system and the research on related key technologies, this paper has completely achieved an assistant system on teaching and learning, which has been put into use in Standard Natural Classroom.