GSM SMS alarm system for elderly people to prevent falls based on 51 microcontroller

Publisher:CrystalClearLatest update time:2023-03-20 Source: zhihu Reading articles on mobile phones Scan QR code
Read articles on your mobile phone anytime, anywhere

1. Project introduction

Topic selection guidance, project sharing: Lighter-z/embedded base

1.1 System composition

This design consists of STC89C52 microcontroller circuit + ADXL345 acceleration sensor circuit + button circuit + buzzer alarm circuit + DS18B20 temperature sensor circuit + LED light circuit + GSM module circuit + power supply circuit.

1.2 System functions

1. When the board is placed vertically, the buzzer will not sound the alarm. If the board is tilted to a certain angle, the buzzer will sound the alarm. If the correct status is not returned for about 15 seconds, GSM sends an alarm message to the mobile phone: Help me!!.

2. If the temperature exceeds 38 degrees, the buzzer will alarm and the temperature will continue to be too high for about 15 seconds. At the same time, a text message will alarm: has a cold

3. It is designed with a false alarm button. When the buzzer alarms, if the elderly thinks it is a false alarm, then the button will be pressed and the buzzer will stop alarming. If the problem persists, the alarm will still be issued.

4. There are indicator lights showing the SMS processing process.

5. The GSM module is SIM800A. This module is fully compatible with the circuit program of SIM900A and has the same appearance.

2. Partial circuit design

2.1 GSM SIM800A module circuit design

The GSM module is a functional module that integrates GSM radio frequency chip, baseband processing chip, memory, power amplifier device, etc. on a circuit board. It has an independent operating system, GSM radio frequency processing, baseband processing, and provides standard interfaces. The GSM module has all the basic functions of sending SMS text messages, voice calls, GPRS data transmission and other communication based on GSM network. Simply put, the GSM module plus keyboard, display and battery is a mobile phone.

Module application areas: remote monitoring, remote smart meter reading, smart home and vehicle-mounted equipment and other remote communication equipment.

The module interface schematic diagram is shown below:

The specific schematic diagram inside the module is shown below:

2.2 Design of buzzer alarm circuit (active low level)

The circuit is driven by a transistor 9012. As long as the microcontroller control pin is low, the buzzer will sound an alarm, otherwise it will not sound. The buzzer's sound mode can be controlled by controlling the square wave output of the microcontroller pin.

2.3 ADXL345 tilt sensor module circuit design

This design chooses the inclination sensor ADXL345 module to detect relevant status information in real time. The ADXL345 is a small, thin, ultra-low power 3-axis accelerometer with high resolution (13 bits) and a measurement range of ±16g. Digital output data is in 16-bit two's complement format and can be accessed via the SPI (3-wire or 4-wire) or I2C digital interface.

The ADXL345 module interface diagram is shown below:

2.4 DS18B20 temperature sensor module circuit design

DS18B20 is a commonly used digital temperature sensor. It outputs a digital signal and has the characteristics of small size, low hardware overhead, strong anti-interference ability and high precision.

The DS18B20 interface diagram is shown below:

3. Partial code display

3.1 ds18b20 initialization

bit Init_DS18B20(void)

{

 bit dat=0;

 DQ = 1; //DQ reset

 DelayUs2x(5); //Slight delay

 DQ = 0; //The microcontroller pulls DQ low

 DelayUs2x(200); //The exact delay is greater than 480us and less than 960us

 DelayUs2x(200);

 DQ = 1; //pull the bus high

 DelayUs2x(50); //Receive presence pulse of 60-240us after 15~60us

 dat=DQ; //If x=0, the initialization is successful, if x=1, the initialization fails

 DelayUs2x(25); //Return with a slight delay

 return dat;

}

3.1 ADXL345 initialization

void Init_ADXL345()

{

   Single_Write_ADXL345(0x31,0x0B); //Measurement range, plus or minus 16g, 13-bit mode

   Single_Write_ADXL345(0x2C,0x08); //The rate is set to 12.5

   Single_Write_ADXL345(0x2D,0x08); //Select power mode

   Single_Write_ADXL345(0x2E,0x80); //Enable DATA_READY interrupt

   Single_Write_ADXL345(0x1E,0x00); //X offset is written according to the status of the test sensor

   Single_Write_ADXL345(0x1F,0x00); //Y offset is written according to the status of the test sensor

   Single_Write_ADXL345(0x20,0x05); //Z offset is written according to the status of the test sensor

}


Reference address:GSM SMS alarm system for elderly people to prevent falls based on 51 microcontroller

Previous article:Design of LED Chinese character dot matrix scrolling display based on AT89C51 microcontroller
Next article:Based on 51 microcontroller wireless Bluetooth APP control LED light brightness design

Recommended ReadingLatest update time:2024-11-16 13:32

Inspection and final test methods for GSM/UMTS mobile phones
With UMTS coverage now available in many centers and more than a dozen dual-mode GSM/UMTS phones on the market, repair centers are faced with the question of what tests to perform on phones when a phone fault is reported and before the repaired phone is returned to the customer. This article describes the main parts of
[Test Measurement]
Inspection and final test methods for GSM/UMTS mobile phones
Oil tank area monitoring system based on GSM short message
1 Introduction The oil tank area monitoring system is a basic component of the oil depot reserve company. At present, most oil tank areas generally have problems such as backward technology, low automation level, and manual work. Therefore, in order to adapt to the requirements of market competition and improve the
[Microcontroller]
Oil tank area monitoring system based on GSM short message
GSM SMS alarm system for elderly people to prevent falls based on 51 microcontroller
1. Project introduction Topic selection guidance, project sharing: Lighter-z/embedded base 1.1 System composition This design consists of STC89C52 microcontroller circuit + ADXL345 acceleration sensor circuit + button circuit + buzzer alarm circuit + DS18B20 temperature sensor circuit + LED light circuit + GSM module
[Microcontroller]
Latest Microcontroller Articles
  • Download from the Internet--ARM Getting Started Notes
    A brief introduction: From today on, the ARM notebook of the rookie is open, and it can be regarded as a place to store these notes. Why publish it? Maybe you are interested in it. In fact, the reason for these notes is ...
  • Learn ARM development(22)
    Turning off and on interrupts Interrupts are an efficient dialogue mechanism, but sometimes you don't want to interrupt the program while it is running. For example, when you are printing something, the program suddenly interrupts and another ...
  • Learn ARM development(21)
    First, declare the task pointer, because it will be used later. Task pointer volatile TASK_TCB* volatile g_pCurrentTask = NULL;volatile TASK_TCB* vol ...
  • Learn ARM development(20)
    With the previous Tick interrupt, the basic task switching conditions are ready. However, this "easterly" is also difficult to understand. Only through continuous practice can we understand it. ...
  • Learn ARM development(19)
    After many days of hard work, I finally got the interrupt working. But in order to allow RTOS to use timer interrupts, what kind of interrupts can be implemented in S3C44B0? There are two methods in S3C44B0. ...
  • Learn ARM development(14)
  • Learn ARM development(15)
  • Learn ARM development(16)
  • Learn ARM development(17)
Change More Related Popular Components

EEWorld
subscription
account

EEWorld
service
account

Automotive
development
circle

About Us Customer Service Contact Information Datasheet Sitemap LatestNews


Room 1530, 15th Floor, Building B, No.18 Zhongguancun Street, Haidian District, Beijing, Postal Code: 100190 China Telephone: 008610 8235 0740

Copyright © 2005-2024 EEWORLD.com.cn, Inc. All rights reserved 京ICP证060456号 京ICP备10001474号-1 电信业务审批[2006]字第258号函 京公网安备 11010802033920号