I. Introductionto the "Water Shield" Flood Control Safety Early Warning System
"Water Shield" flood prevention safety early warning system(hereinafter referred to as "water shield" system) is mainly composedof 5 major parts: client, forwarding relay system host, system software, alarmterminal.
The client of the "Water Shield" system is worn in the client'sswimming cap, and the client sends out the specified code signal at regularintervals. When the client is in the air, the code signal can be smoothlytransmitted to the forwarding relay, and the forwarding relay sends the codesignal to the system host; when the client enters the water, the signaltransmission is blocked due to the absorption of electromagnetic waves bywater, at this moment The host side cannot correctly receive the code signalfrom the client, and the host side records the time when the client receivedthe last signal, and compares it with the current time. When the time exceedsthe upper limit of the specified value, the host sends a waterlogging warning.Lifeguards check for danger.
The following mainly explains the application of the "water shield"system:
Second, thesuccessful application of wireless modules in the "water shield"system
In the "water shield" system, the client needs to communicate withthe forwarding relay for data communication, the forwarding relay needs tocommunicate with the system host, and the system host needs to communicate withthe alarm terminal. The use of wireless modules for these data communicationshas become an optimal choice, with a simple installation method, no wiring onsite, and no structural changes to the field environment. However,high-frequency wireless communication has special hardware and software, andmust be designed and produced by professional companies.
The "Water Shield" system described in this article uses threewireless modules from the company. The wireless module ZMSD of the client andthe wireless module E05-MLE124AP2 of the forwarding relay perform wirelesscommunication based on the 2.4G frequency.
The code signalreceived by the wireless module E05-MLE124AP2 of the relay relay is transmittedto the single-chip microcomputer through the serial port UART, and then thesingle-chip microcomputer transmits the E31-TTL-1W to the wireless modulethrough another serial port UART, and the wireless module E31-TTL-1W thatforwards the relay. The wireless module E31-TTL-1W with the system hostperforms wireless communication based on the 433M frequency. Similarly, thedata communication between the system host and the alarm terminal is also basedon the wireless module E31-TTL-1W.
Third, thewireless module introduction
1, ZMSD
Application of wireless module in "Water Shield" flood preventionsafety warning system
The module is a 2.4GHz wireless module, designed and developed by the NorwegianNordic company imported nRF24LE1E RF chip, QFN32 type, built-in 51 single-chipmicrocomputer, stable performance, high communication speed, software can bewritten, the client sends out the specified code signal at regular timing.
2, E05-MLE124AP2
The module is a 2.4GHz wireless module. It is designed and developed by theNorwegian Nordic company's imported nRF24LE1D RF chip. The QFN24 is equippedwith the US imported PA and LNA integrated chip RFX2401C, which amplifies thepower to 100mW and improves the receiving sensitivity. nRF24LE1D built-in 51single-chip microcomputer, stable performance, high communication rate, canwrite software, forwarding relay through E05-MLE124AP2 has been receiving codesignals from the client.
3, E31-TTL-1W
The module is a 433MHz wireless serial port module (UART) based on Swiss AXSEMimported AX5043 RF chip, half-duplex, transceiver integrated, transparenttransmission mode, transmission power 1W, working in 425– 450.5MHzfree band (default 433MHz), TTL Level output with air wake up.
The module has a software FEC forward error correction algorithm, which has highcoding efficiency and strong error correction capability. In the case of suddeninterference, it can actively correct the interfered data packets, greatlyimproving reliability and transmission distance.
The module has data encryption and compression capabilities. The datatransmitted by the module in the air is random, and the data interception ismeaningless through strict encryption and decryption algorithms. The datacompression function has the probability of reducing the transmission time,reducing the probability of interference, improving reliability andtransmission efficiency.
After the forwarding relay obtains the code signal from the client, ittransmits it to the system host through the E31-TTL-1W, and the signalpenetrating wall is strong, and the signal dead angle is eliminated, so that awide wireless signal space can be enjoyed.
V. Conclusion
Today, with the rapid development of the electronics industry, top industrycompanies rely on technological innovation to support SCM, RF technology,Internet of Things, and wearable technology in various industries throughstrong alliances and complementary advantages. The "water shield"system introduced in this paper can be widely applied to the swimming industry,greatly reducing the risk of swimmers' death and solving the problems inswimming pool management.
Keywords: "water shield" system, client, forwarding relay, systemhost, wireless module
