Function Introduction
- Using STM32 microcontroller as the main control system;
- OLED LCD current real-time distance, safety distance, current latitude and longitude information;
- Ultrasonic detection is less than the set safety distance, the buzzer alarm prompts: below the safety distance!
- Ultrasonic detection of the current obstacle distance, GPS positioning;
- The photosensitive sensor detects the strength of the current environment, and the LED lighting indicator is turned on when the light is dark;
- ADXL345 three-axis sensor detects whether the elderly has fallen;
- Press the button to set the minimum safe distance setting, the number accepted by SMS;
- In case of emergency, you can directly dial and hang up the phone;
- ADXL345 tilt exceeds the time to detect the fall of the elderly, make a call, send a text message and the current latitude and longitude, and display the corresponding prompt on the LCD screen
- The whole circuit is powered by 5v;
Circuit Diagram
PCB
source code
#include <reg52.h>
#include <intrins.h>
#include <stdio.h>//printf serial output header file
#define uchar unsigned char
#define ushort unsigned int
#define uint unsigned long
#include "lcd1602.h"
#include "uart_trx.h"
#include "eeprom52.h"
#define RATIO 800 //Coefficient, it is recommended to choose 800-1000
sbit key1 = P1^0;//add key
sbit key2 = P1^1;//minus key
sbit beep = P2^0;//buzzer
sbit Fan = P1^3;//fan
unsigned char pmBuf[7] = 0;//data receiving array
uint PM25_Value = 0; //PM = ((pmBuf[1]<<8) + pmBuf[2])/1024*8*ratio
uint PM25_ValueMax = 200; //upper limit initial value
void EEPROM_WRITE()//EEPROM write
{
SectorErase(0x2000);//Erase sector
byte_write(0x2001, (PM25_ValueMax>>8) & amp;0xFF);//store high 8 bits
byte_write(0x2002, (PM25_ValueMax>>0) & amp;0xFF);//store the lower 8 bits
byte_write(0x2009, 111);//store check value
}
void EEPROM_READ()//EEPROM read
{
if(byte_read(0x2009)!=111)//Start up to detect whether the MCU is used for the first time, if it is not the first time, store the data first, and then read, the data will not be garbled
{
EEPROM_WRITE();//storage
delay_ms(100);
}
PM25_ValueMax = byte_read(0x2001)<<8 | byte_read(0x2002);//read the upper limit value
}
void Get_PM(void)//Read the PM2.5 value, the specific meaning of the data frame, please refer to the chip manual
{
char i = 0;
char j = 0;
char k = 0;
COM.RX_Cnt = 0;
if(COM.B_RX_OK == 1)//Serial port data reception is complete
{
for(i = 0; i<8; i ++ )
{
if((RX_Buffer[i] == 0xAA) & amp; & amp;(RX_Buffer[i + 6]==0xFF))//judging whether the received data is correct
{
goto find2;
}
}
goto end2;
find2:
for(j = 0; j<7; j ++ )
{
pmBuf[j] = RX_Buffer[i + j];//Data acquisition
}
PM25_Value = (unsigned int)((pmBuf[1]*256) + pmBuf[2])*5/2048.0*RATIO;//calculate PM2.5 value
COM.B_RX_OK = 0;
}
end2:
return;
}
void main(void)
{
unsigned int test;
EEPROM_READ();//Start up and read the stored value
LCD_init();//1602 initialization
Uart_Init(2400);//Serial port initialization baud rate 2400
LCD_write_string(0,0,"Pm2.5: ug/m3");
LCD_write_string(0,1,"PmMax: ug/m3");
// display upper limit
LCD_write_char(7, 1, PM25_ValueMax % 1000 / 100 + 0x30);
LCD_write_char(8, 1, PM25_ValueMax % 100 / 10 + 0x30);
LCD_write_char(9, 1, PM25_ValueMax % 10 + 0x30);
while(1)
{
if (test + + > 250)//Read once in about 250ms
{
test = 0;
Get_PM();//Get PM2.5
if(PM25_Value > 999)//limit value, maximum 999
PM25_Value = 999;
//Display PM2.5
LCD_write_char(7, 0, PM25_Value % 1000 / 100 + 0x30);
LCD_write_char(8, 0, PM25_Value % 100 / 10 + 0x30);
LCD_write_char(9, 0, PM25_Value % 10 + 0x30);
\t\t\t\t\t
if(PM25_Value >= PM25_ValueMax)//Exceed the upper limit, buzzer alarm
{
beep = ~beep;
Fan = 0;
delay_ms(100);
}
else
{
beep = 1;
Fan = 1;
}
}
if(key1 == 0)//Press the key
{
delay_ms(10);//Debounce
if(key1 == 0)
{
beep = 0;
delay_ms(100);
beep = 1;
while(key1 == 0);
if(PM25_ValueMax<999)PM25_ValueMax + =10;//The upper limit is up to 999, add 10 each time
\t\t\t\t\t\t //show
LCD_write_char(7, 1, PM25_ValueMax % 1000 / 100 + 0x30);
LCD_write_char(8, 1, PM25_ValueMax % 100 / 10 + 0x30);
LCD_write_char(9, 1, PM25_ValueMax % 10 + 0x30);
EEPROM_WRITE();//Save
}
}
if(key2 == 0)//minus key pressed
{
delay_ms(10);
if(key2 == 0)
{
beep = 0;
delay_ms(100);
beep = 1;
while(key2 == 0);
if(PM25_ValueMax>=10)PM25_ValueMax-=10;//The upper limit is at least 0, every time minus 10
\t\t\t\t\t\t //show
LCD_write_char(7, 1, PM25_ValueMax % 1000 / 100 + 0x30);
LCD_write_char(8, 1, PM25_ValueMax % 100 / 10 + 0x30);
LCD_write_char(9, 1, PM25_ValueMax % 10 + 0x30);
EEPROM_WRITE();//save
}
}
delay_ms(1);
}
}
Component list
| Single-chip computer-based navigation for the blind, smart crutches for the elderly, anti-lost, anti-fall, and short message positioning | ||
| Name | Model | Quantity |
| MCU | STC89C52 | 1 |
| IC seat | DIP40 | 1 |
| Universal board | 9*15cm | 1 |
| Crystal oscillator | 11.0592M | 1 |
| Electrolytic capacitor | 10uF | 1 |
| Electrolytic capacitor | 1000uf | 1 |
| Ceramic capacitor | 22pF | 2 |
| Resistance | 10K | 3 |
| Resistance | 1K | 4 |
| resistor | 2K | 1 |
| LED red | 5MM | 1 |
| LED Green | 5MM | 1 |
| Buzzer | Active | 1 |
| Transistor | S9012 | 1 |
| Keys | 5 | |
| Display | LCD1602 | 1 |
| Pin header | 16P | 1 |
| Row mother | 16P | 1 |
| Human infrared Module | HC-SR501 | 1 |
| female row | 3P | 1 |
| Temperature Sensor | DS18B20 | 1 |
| Smoke Sensor | MQ-2 | 1 |
| Analog to Digital Converter | ADC0832 | 1 |
| IC seat | 8P | 1 |
| GSM module | SIM800c | 1 |
| power socket | 5MM | 1 |
| Power cord | 5V2A | 1 |
| Self-locking switch | 1 | |
| relay | 1 | |
| Small water pump | 1 | |
| wire | Several | |
| Solder wire | Several |
References
references
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