Building a system to monitor water level, temperature and send warnings via SMS/GSM network

INTRODUCTION

Remote water level monitoring system via SMS. Is an application of science and technology that is being researched and applied to warn as early as possible about flood levels that can cause human damage, and evacuate as quickly as possible. This system is compact and works effectively without much maintenance. The system will be placed in the most sensitive places such as the headwaters of rivers, where the system will measure and report water levels via SMS to the monitoring stations as quickly and accurately as possible. From there, we can monitor water levels and evacuate early when there is a risk of flooding.

The project was researched, surveyed and implemented with the aim of applying the knowledge learned in school to design and create a complete SMS-based remote water level and temperature monitoring system. The system integrates the Sim900 module and the infrared sensor system. For the sensor system, there are sensor LEDs placed facing each other, and transmit data when there is an obstacle blocking those sensor LEDs. After processing, the data will be sent to the operator's terminal (mobile) to notify the water level at which warning level or normal water level.

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To perform the above functions, I have researched and studied issues related to the topic such as: PIC16F877A family, Sim900 Module, corresponding programming languages such as CCS, AT Command set for Module, and other issues related to the topic.

The scientific significance of the system is to limit the damage caused by floods, to limit the heavy loss of life and property. Not stopping there, the system will gradually develop in many aspects, in addition to flood warnings, it will also warn to reduce many other damages caused by natural disasters such as forest fires, storms, earthquakes, tsunamis, etc.

Technology is endless, knowing how to apply it in practice will contribute great benefits to the society which is developing strongly day by day. Therefore, I chose the topic " Building a system to monitor water level, temperature and send warnings via SMS/GSM network " to serve the work of flood prevention and reduce human damage.

This topic consists of 4 chapters:

Chapter 1: Overview of GSM network and SMS messaging service Chapter 2: PIC16F877A microcontroller

Chapter 3: Design and build a system to sense and send warnings about water level and temperature via SMS network

Chapter 4: Results achieved by the system

CHAPTER 1. OVERVIEW OF GSM NETWORK AND SMS MESSAGING SERVICE

1.1 OVERVIEW OF SMS MESSAGES

1.1.1 Introduction to SMS

SMS stands for Short Message Service. It is a technology that allows sending and receiving messages between phones. SMS first appeared in Europe in 1991. At that time, it included the GSM (Global System for Mobile Communications) standards. Later, it evolved to wireless technologies such as CDMA and TDMA. GSM and SMS standards were originally developed by ETSI. ETSI stands for European Telecommunications Standards Institute. Today, 3GPP (Third Generation Partnership Project) is in charge of developing and maintaining GSM and SMS standards.

As mentioned above the full name of SMS is Short Message Service, from that phrase, it can be seen that the data that can be stored by an SMS message is very limited. An SMS message can contain a maximum of 140 bytes (1120 bits) of data. Therefore, an SMS message can only contain:

+ 160 characters if 7-bit character encoding is used (7-bit character encoding is suitable for encoding Latin characters such as English alphabet characters).

+ 70 characters if Unicode UCS2 16-bit character encoding is used (SMS messages that do not contain Latin characters such as Chinese characters must use 16-bit character encoding).

SMS text messaging supports many different languages. It works well with many languages that support Unicode, including Arabic, Chinese, Japanese, and Korean. Besides sending text messages, SMS messages can also carry binary data. It also allows sending ringtones, pictures, and many other utilities … to another phone.

One of the main advantages of SMS is that it is supported by all GSM phones. Almost all the additional features including low-cost SMS services are provided using wireless carriers. Unlike SMS, mobile technologies such as WAP and mobile Java are not supported on many phone models.

The use of SMS messaging is growing and becoming more widespread:

- SMS messages can be sent and read at any time.

Nowadays, almost everyone has their own mobile phone and carries it with them almost all day long. With a mobile phone, you can send and read SMS messages anytime you want, no matter if you are in the office or on the bus or at home…

- SMS messages can be sent to phones that are powered off.

If you are unsure about a call, you can send an SMS message to your friend even if his phone is off when you send the message. The phone network's SMS system will store the message and then send it to your friend when his phone is on.

- SMS messages are less annoying while you can still stay in touch with others

Reading and writing SMS messages is noiseless. Whereas you have to run out of the theater, library or somewhere to make or answer a phone call. You don't have to do that if SMS is used.

The phones are mobile and they can be changed between different Wireless carriers.

SMS messaging is a very successful and mature technology. All mobile phones today support it. Not only can you exchange SMS messages with mobile users on the same wireless carrier, but you can also exchange them with users on other carriers.

- SMS is a technology suitable for Wireless applications used in conjunction with

It.

That is because:

First, SMS messaging is 100% supported by phones that use the system.

GSM system. Building wireless applications on top of SMS technology can maximize the applications available to users.

Second, SMS messages are also compatible with carrying binary data besides sending text. It can be used to send ringtones, pictures, animations.

Third, SMS messages support online payment for services.

1.1.2 Structure of an SMS message

The content of a sent SMS message will be divided into 5 parts as follows:

- Instructions to air interface : Instructions for data connection to air interface.

- Instructions to SMSC : Data instructions to connect to the SMSC (short message service centre).

- Instructions to handset : Handshake connection data instructions.

- Instructions to SIM (optional): Instructions for connection data, SIM identification (Subscriber Identity Modules).

- Message body: SMS message content.

1.1.3 String SMS messages

One of the drawbacks of SMS technology is that SMS messages can only carry a limited amount of data. To overcome this, an extension called serial SMS (or long SMS) was developed. A long text SMS message can contain more than the 160 characters used in English. The basic mechanism of serial SMS works as follows: the sender's mobile phone will divide the long message into several smaller parts and then send these parts as a single SMS message. When these SMS messages have completely reached their destination, they are combined together on the recipient's mobile phone.

The difficulty with string SMS is that it is much less supported than SMS on devices that use wireless waves.

1.1.4 SMS CENTER/SMSC

An SMS Center (SMSC) is responsible for the routing of SMS-related activities of a wireless network. When an SMS message is sent from a mobile phone, it is first sent to an SMS center. The center then

This SMS will forward this message to the destination (recipient). An SMS message may have to pass through more than one network entity (such as SMSC and SMS gateway) before reaching its actual destination. The sole responsibility of an SMSC is to forward SMS messages and regulate this process in its cycle. If the recipient's phone is not in the receiving state (powered on) at the time of sending, the SMSC will store the message. And when the recipient's phone is powered on, it will send the message to the recipient.

Typically, an SMSC is dedicated to the transfer of SMS traffic in a wireless network. The network operator always manages its own SMSC and its location within the wireless network. However, the network operator will use a third SMSC located outside the wireless network.

You must know the SMSC address of the wireless network operator to use and configure the SMS messaging function on your phone. Typically an SMSC address is a regular telephone number in international format. A phone should have a menu option to configure the SMSC address. Usually the address is reset in the SIM card by the wireless network operator. This means that you do not need to make any changes.

1.1.5 International SMS messaging

Inter-operator SMS messages are divided into two categories: local inter-operator SMS messages and international inter-operator SMS messages. Local inter-operator SMS messages are messages sent between operators within the same country, while international inter-operator SMS messages are SMS messages sent between wireless network operators in different countries.

Usually the cost to send an international SMS is higher than sending a domestic one. And the cost to send a message within the same network is less than sending to another network in the same country <= the cost for sending an international SMS.

The ability to interoperate SMS messages between local or even international wireless networks is a major factor contributing to the rapid growth of the global SMS system.

1.2 OVERVIEW OF GSM MOBILE INFORMATION SYSTEM

1.2.1 Introduction to GSM mobile communication system

GSM (Global System for Mobile communication) is a global digital mobile information system, a 2G (second generation) wireless technology with a cellular network structure, providing high-quality voice transmission and data transfer services with different frequency bands: 400Mhz, 900Mhz, 1800Mhz and 1900Mhz, specified by the European Telecommunications Standard (ETSI).

GSM is an open architecture system so it is completely hardware independent, people can buy equipment from many different manufacturers.

Because it is present almost everywhere in the world, when service providers sign roaming agreements with each other, GSM subscribers can easily use their GSM phones anywhere.

The great advantage of the GSM system is that in addition to transmitting high-quality voice, it also allows subscribers to use other cheaper communication methods, such as SMS messages. In addition, to facilitate service providers, the GSM system is built on an open system basis, so it is easy to connect different devices from different equipment suppliers.

It allows service providers to offer roaming to their subscribers with other networks around the world. And the GSM system also developed additional data transmission features such as GPRS and later higher speed transmission using EDGE.

GSM currently accounts for 85% of the mobile market with 2.5 billion subscribers in 218 countries and territories. GSM mobile networks allow roaming with each other so GSM mobile phones from different GSM networks can be used in many places around the world.

1.2.2 Characteristics of GSM mobile communication system

- Allows sending and receiving text messages up to 126 characters long.

- Allows data transfer and reception, FAX between GSM networks at current speeds up to 9,600 bps.

- High coverage: The GSM system not only allows handover within the entire network but also between GSM networks globally without any change.