The green laser pointer has integrated the computer cursor control technology
1.2 control algorithm selection and demonstration program: Option One: the use of two photodiodes collected light signal, two signals by constantly comparing the size to control the motor rotation because the two signals exposure to environmental impact, and interference with large, easy to cause the motor to oscillate in a wide range, resulting in tracking the source side to side. Option II: theory, through the program were compared in two pairs of two with multiple photodiode for light processing, said at the size of the photodiode voltage signal to control the motor rotation direction, due to the performance of each photosensitive diode parameters can not be exactly the same, the measured voltage signal is not completely accurate, it is difficult to achieve the desired effect, this program is not easy to achieve. Laser pointer function of green laser pointer: There’s LED working indicator light and the laser indicating distance is beyond 200m.Option III : the use of multiple photodiodes divided into two groups, which are located on both sides to track the source, many times through the program three AD samples, using an average filter principle, for each channel photodiode to the many measured data averaged AD calculation, and then each group the average income of each photodiode for summation, and then to compare two voltages and by the results of the first voltage comparator control deflected direction of the motor, using the mean filter principle, be effective against ambient light interference, while controlling the deflection direction of the motor are also relatively stable, but also easy to implement in practice.Mouse function of green laser pointer: It contains all functions a mouse has and it is convenient to use the left and right keys. Diagram as shown below. program to determine the advantages and disadvantages of the above program, the design uses a photodiode as sensing devices, MSP430 4 the deceleration stepper motor control program, a small laser pointer to drive the rotation angle, and the use of the principle of mean filtering algorithm control to achieve precise positioning of the light source function over several demonstration programs to explore the program verification, photodiode light detection step with deceleration into the laser pointer tracking motor drive can basically achieve the point source tracking function, to the subject requirements and practical. Keyboard function of green laser pointer: It could turn pages, quick play and blank screen the demonstrating files.Second, the overall design of a system, overall system hardware circuit diagram laser pointer optical signal processing right photodiode signal amplification photosensitive laser pointer on the left AD sample button LED display and 430 single-chip microcontroller stepper motor drive circuit 2 laser pointer tracking, system software design diagram began collecting compensation for a self-test mode to determine the mode 0 auto mode, manual mode, so turn left> right-left comparison sample voltage < Right Left = Right (offset voltage) left-right side still 5 Third, the system unit 1,430 smallest single-chip circuit design, system board Figure 2, the stepper motor drive circuit L298n as a gear motor drive circuit is a constant voltage constant current bridge driver chips, with 4-channel logical drive circuit. can drive two DC motors or a two-phase stepper motor, the output voltage up to 50V, output current up to 2 ~ 4A, can be directly used to provide signal microcontroller IO port, external circuit is simple, easy to use this two-phase design of the main drive gear motor.Wireless technology of green laser pointer: It applies wireless RF technology and the remote control is direction-free.

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