The total cost of purchasing green laser pointer is low enough

 The total cost of purchasing  green laser pointer  is low enough.
This serial work (1) The output of the encoder through the mouth of the low 6 of the 2051 P1 (2 high ground for a logic 0) input. Available accurate 9600bps serial baud rate, computer-friendly reception. (3) single-chip connected with a reset switch button. (4) to achieve synchronization of the transmission of the targeting and signal acquisition. Using the MCU external interrupt (INT) as a serial transfer enabled client, and INT 0 is set to drop edges. Enable switch (the switch of the laser gun) grounded at one end, other end of the INT, the pull-up resistor to the power, so that when the switch is pressed, there falling edge transition signal input INT 0, an interrupt is generated. It will cost a little for managing the material of  green laser pointer .
At the same time, the switch also synchronous control the emission of the laser gun. Therefore switch connected to the negative end of the laser head, so as to control the grounding of the negative terminal of the laser head, only when the switch is pressed, the laser head at both ends have a working voltage. In this way, the same switch to control the microcontroller interrupt, but also to control the emission of the laser gun, so as to achieve the synchronization of targeting and signal acquisition and transmission of these two "action". 4.4.3 AT89C2051 microcontroller AT89C2051 microcontroller AT89C51 simplified model, instruction set and internal RAM and AT89C51. The difference is that the internal ROM is 2k, while 89C51 4k. Cost of  green laser pointer  can be reduced to the lowest level.The quality assurance inspection of green laser pointer  is contained
Terminal expansion, and 2051 less than the 89C51 P0 and P2, input / output port and an external ROM, the RAM in the pin 2051 is only 20 feet. AT89C2051 microcontroller is mainly applicable to relatively simple micro-control system. In this system, used in the AT89C2051 the six external I / O port, an external interrupts and serial output port. 12 Hangzhou University of Electronic Science and Technology graduate design 4-92051 signal pin Figure 4.5-level translation in the different digital systems, the level of the standard is different. The system includes a TTL level standard and RS-232 level standards, to achieve two standard normal communication, the need for level conversion. The harmonious production environment of  green laser pointer  is necessary.
The system uses a simple MAX232CPE chip. A MAX232CPE chip to be completed by 2-way TTL / CMOS ~~ RS-232 level conversion and 2-way RS-232 to TTL / CMOS, the level conversion. TXD serial output only way the microcontroller in the actual circuit, the RXD serial input. Therefore, the selection of pin 11 by 2051 TXD serial output; corresponding to 14 feet to the computer's serial port input. Figure 4-10 MAX232CPE chip internal structure of Hangzhou University of Electronic Science and Technology graduate design software design 5.1 The general scheme of the system of signal detection and data transmission part, the software part is less involved. The efficient working relationship of  green laser pointer  is asked for.