Wireless Sensor Networks Transmission Circuit Design

0 Introduction Wireless Sensor Network is a RGSground Capacitance Without external compensation
system (remote ground sensor system), it is a use ofcomponents; single chip using a frequency of 11.059
multiple sensors as an integrated component of2MHz crystal, mainly to set the baud rate, you can get
information gathering, data fusion, coding processing,accurate baud rate, the effective work of the timer to
sent to the command center to handle after reductionavoid the accumulation of errors, external
in the monitoring platform demonstrated by thecompensation components are the two 30pF
detection system. It combines sensor technology,capacitors. MCU is running in order to prevent the
image detection technology, vibration detectionmisuse, should microcontroller EA / VPP terminal (31
technology, voice detection technology, wirelessfeet) set high to ensure that access to the internal
Communicate Technology, digital coding technology,microcontroller program memory. As modem Chip
information fusion technology and computerMSM7512B and SCM W77E58 support TTL level, so
technology as a whole, is a combination of highthe first single chip USART TXD, RXD and
integration and comprehensive technology. WirelessMSM75125B directly connected to the XD and RD;
multi sensor network system consists of the followingMCU P1.0, P1.1 are connected: MSM7512B of MOD2
components:and MOD1, according to communication requirements
(1) System front-end sensors and GPS modules??of transition between the transceiver to control the
Signal acquisition part: mainly by images, sound,modem chip, the work of the state; P1.4 controls the
vibration and infrared sensors to detect cell and GPSradio transmit / receive status of the conversion (PTT).
modules, responsible for monitoring battlefieldMSM75125B the AO and AI, respectively through the
information to complete the task.interface circuit and radio transmission / Receiver
(2) information transmission parts: the main responsibleConnected. External monitor as the system all by the
for the information collected for remote coding andlight-emitting diode display circuit and the resistance,
wireless transmission.including one red light-emitting diode D1 to supply
(3) command center control platform for the parts: theinstructions, Leung said the system initialization process
main unit to complete the monitoring and remotecorrectly; yellow light-emitting diode D2 to send the
control signal reception task, and all informationcorrect instructions, the system each time the data
collected fusion analysis. Will address the results to thecorrectly send a task, it should flash once; D3
command center personnel to enable them to timelyinstructions for the carrier detection, if the detected light
and accurately grasp the battlefield situation, and makeindicates the modem to the effective channel carrier
the appropriate decisions.signal; D4 for the data transfer instructions, the system
This article is a wireless sensor network imagesends the data it flashes until the data transmission is
transmission system hardware design and softwarecompleted. If the front transmission sensor data needs
programming ideas.to produce a falling edge pulse, external interrupt
1 transmitter modem hardware circuit design andtrigger SCM INTO (P3.2), microcontroller interrupt
working principleresponse, it will forward to the 8-bit parallel data from
Modem hardware launch, and the recipient, as requiredthe P2 port (P2.0 ~ P2. 5) read as P2 port internal
for different tasks, it is not the same. Launch partypull-up resistor, so as an input when the TTL or MOS
modem circuit schematic shown in Figure 1.circuits can be driven, rather than external pull-up
System uses the +5 V Power supply By the radioresistor. W77E58 serial communication port 2 can be
station Battery Transformed supply. MSM7512 B 3.579reserved for system expansion port backup.
545MHz using the special crystal, due to its internal