With the development of integrated circuits, wireless communication technologies, and embedded technologies, wireless communication networks also comegoing, wireless sensing networks have low power, low cost, distributed and self-organizing features. The traditional wireless RF communication module is large, and the chip needs to control the chip to control the RF module, which increases the cost of the design, and the mobility is not good.
The continuous advancement of semiconductor technology allows the processor chip to be integrated into a small volume, and the price has become less expensive, and the dedicated wireless network chip and technology are also developed. The CC430F5137 designed in TI is used in this paper, which implements a node module applied to the wireless network. CC430F5137 is a chip that integrates RF nucleus. It has a CC1101 RF core. You can complete data acquisition, processing, transmission and reception of data using a single chip, so that the volume of the circuit board can become smaller, cheaper. In order to realize the low power design of the network node, this article uses the wireless wake-up (Wor) function of the RF module. At the same time, the algorithm of RF transmission is improved by using the Idle Channel Evaluation (CCA) function of the RFQ, and the accuracy of the multi-node is transmitted to the repeater module.
Overall design plan
The wireless sensor network is a network that is deployed in a large number of inexpensive micro sensor nodes in the monitoring area. It is a wireless network constructed from a large number of still or moving sensors in a self-organizing and multi-hop, in a collaborative manner, and the information that is perceived, acquired, processing, and transmitting the network covers information in the geographic area, and ends this information. Send to the network owner. The wireless sensor network mainly implements three functions of data collection, processing, and transmission.
The sensor network node is generally affected by the working environment, and the power consumption problem is to be considered first. Considering the design of low power requirements, the master MCU of the node device selects the CC430F5137, which uses its built-in RF communication module to perform RF communications. Battery is powered by the characteristics of its low power consumption. The software part uses the wireless wake-up function of CC1101 to reduce system power consumption.
Multiple node devices can be hung in the wireless sensor network, while the address of each node device must. The node devices designed herein use the DIP switch to set the address of each node device to ensure that each node has an address. Access to sensor devices via the SPI interface or I2C bus, you can flexibly access different models of sensor devices to achieve different physical quantities. The system structure of the node is shown in Figure 1.
Overall design of node circuit
The CC430F5137 has a supply voltage range of 1.8 to 3.6 V, and the degree of degrees is selected to provide 3 V of DC voltage. The setting of the mating software can reduce power consumption. The key portion of the system is that the radio frequency transmission utilizes a radio antenna module to ensure the stability of RF communications, which is accessed by both the RF_N and RF_P of the chip. In addition, a 26 MHz crystal is accessed based on the need for RF transmission.
The P1.5, P1.6, P1.7 pins of CC430F5137 can be used for serial communication and SPI communication, using these three pins as serial debugging, additional P1.1, P1.2, P1.3 pins can be used The SPI and I2C bus communications, these three interfaces are used to reserve a chip that connects the sensor. The main circuit diagram of the system is shown in Figure 2.
In order to make the address of each node, the address setting is performed using the 8-bit Dial Switch SW. As shown in FIG. 3, the address of the terminal node can be set by the dial switch, and 255 different addresses can be set, each terminal node sends data as a slave device, and then transmitted by the relay node to use The main control MCU management of network management, completes the transmission of wireless sensor network data.
This paper uses TI's CC430F5137 chip, wireless data acquisition nodes designed with RF communication technology, which can greatly reduce the volume of the system. The system can collect a wide variety of signals to securely transfer the collected data to the intermediate data acquisition point. Designing Carrying Monitoring Functions and Channel Idle Evaluation Function Improved RF transmit functions can effectively improve the anti-interference when multiple nodes simultaneously transmit data.
Be
Source: Wiku Electronic Market Network
Our other product:
