Based on the nRF2401 Smart Wireless fire monitoring system design (1)

Introduction

Fire monitoring system in relation to a building in people's lives and property security, throughout the intelligent construction, the fire monitoring system plays a very important role. Traditional fire monitoring system does not meet the requirements of timely alarm mainly focus on the problem in two ways: first, when building a fire, a traditional fire monitoring system easily because the loss of utility transmission lines damaged, in traditional fire monitoring system makes extensive use of wired communications cable, it is easy to result that intensified the spread of the disaster; Secondly, traditional fire monitor system detectors distribution limited, the direct cause of the fire detection reliability difference, prone to false positives, and not on the entire building is the systematic and comprehensive detection.

This article is designed based on the nRF2401 Smart Wireless fire monitoring system design, the system can make the target area for building effective supervision, and monitoring node volume is small, with no wires to run and move, installation and maintenance convenience.

System overview

Monitoring system by the data collection control node and monitoring terminal. in this article monitoring system uses a star topology that consists of a computer connected to the wireless communications module as a system of monitoring terminal, you can follow the monitoring system in any of the data collection control node communication.

Data acquisition and control node in accordance with certain rules in the various rooms of a building or corridor, is responsible for data collection, processing and transmission, and on monitoring terminal from the analysis of data, order processing, complete the appropriate action. System architecture diagram shown in Figure 1.

Figure 1 system architecture diagram

The fire control system uses a star topology, this topology can scale well, easy to increase the system node, the node distribution in the building of uncertainty, in building room, isolated by placing nodes, avoid Wireless interference and the uncertainty of the monitoring area.

Monitoring terminal and data collection control node is directly connected to, periodically the data collection control node collection data, and data integration, analysis of whether to issue a fire alarm signal. To a certain extent reduce false positives, monitoring and control system to improve wireless fire monitoring system reliability. If there is fire, alarm, while at the same time to the data collection control node issue control directive, start fire fighting facilities.

System hardware

NRF2401 wireless data transfer modules

NRF2401 is Norway Nordic company's single-chip wireless transceiver chip 2.4GHz.

It will be radio frequency, 8051MCU, 9 channel 12-bit ADC and external components, inductance and filter all integrated into a single chip, and adopt 2.4GHz band and MCU μ m technology, provides ShockBurst (premature hair), CRC DuoCeiver, slice and add features such as calculating coding. NRF2401 support communication between multiple points, the highest transfer rates more than 1Mbit/S over Bluetooth with higher transmission speeds. It takes the SoC design, just a few external components to form circuits RF transceiver. With Bluetooth, nRF2401 no complex communications protocols, it is completely transparent to the user, the same kind of free communication between products. More importantly, the nRF2401 cheaper than Bluetooth products. So the nRF2401 is the industry's smallest size, power consumption, minimal, minimal external components of the low-cost RF system-level chip.

Data acquisition and control node

Data acquisition and control nodes as part of monitoring system of the Terminal, in this design was designed as modules that directly with a sensor and fire extinguishing equipment are charged to complete the fire alarm and control functions.

By wireless means and monitoring terminal connected to the receive terminal to their own information, and your information is sent to the Terminal. Data acquisition and control nodes circuit including sensor input, output control interfaces, power connector and wireless communication chip interface, its circuit schematic diagram shown in Figure 2.

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