Project: NodeMCU esp8266-esp12e to connect to another esp8266-esp12e - social distancing - c

Question

I need to ring the buzzer within the range of 1 meter only, my esp8266 is connected to a buzzer but the buzzer will ring on and off within the range of 1 meter using two esp8266, or sometimes it does not ring at all. The project is social distancing, what else should I do? Here is the code I am using:
#include <ESP8266WiFi.h>
const char* APssid = "Social Distancing"; //acess point of the device
const char* APpassword = "qwertyuiop";
const int RSSI_MAX = -37;//maximum strength of signal in dBm
const int RSSI_MIN =-100;//minimum strength of signal in dBm
void setup()
{
WiFi.mode(WIFI_OFF);
WiFi.disconnect();
delay(50); //this part turns off the wifi and resets it if it was already on
Serial.begin(115200);
pinMode(14,OUTPUT);
Serial.println();
WiFi.mode(WIFI_AP_STA); //configuring the board in hybrid mode
Serial.print("Configuring access point...");
WiFi.softAP(APssid, APpassword);
Serial.println(WiFi.softAPIP());
}
void loop()
{
Serial.println("Wifi is scanning");
int n = WiFi.scanNetworks();
Serial.println("Wifi scan ended");
if (n == 0)
{
Serial.println("no networks found");
}
else
{
Serial.print(n);
Serial.println(" networks found");
for (int i = 0; i < n; ++i)
{
//Print SSID and RSSI for each network found
Serial.print(i + 1);
Serial.print(") ");
Serial.print(WiFi.SSID(i));//SSID
Serial.print(WiFi.RSSI(i));//Signal strength in dBm
Serial.print("dBm (");
if(WiFi.SSID(i) == "Social Distancing")
{
if(WiFi.RSSI(i) > -37)//THIS -37 (RSSI) is the threshold value, this value is set
according to the distance of 1m
{
digitalWrite(14,HIGH);//(Generic esp8266 : (14,HIGH) , NodeMCU : (D5,HIGH) )
Serial.println("Social Distancing");
break;
}
}
else
{
digitalWrite(14,LOW);
}
}
delay(50);
}
Serial.println("");
delay(50);
WiFi.scanDelete();
}

Answer 1

Hi Lisa I have modified your code and I have added a 64x48 OLED display connected to the I2C connections, to visualize the results and it works beautifully. Moreover I have used the built in led (see: LED_BUILTIN) instead of the buzzer.
You have had a great idea. Now it works great and you can interrogate any Access point.
Please find attached the code:
//OLED
#include <Arduino.h>
#include <U8g2lib.h>
#include <U8x8lib.h> //this one in use
#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif
U8X8_SSD1306_64X48_ER_HW_I2C u8x8(/* reset=*/ U8X8_PIN_NONE); // EastRising 0.66" OLED breakout board, Uno: A4=SDA, A5=SCL, 5V powered
// End of constructor list
#define U8LOG_WIDTH 16
#define U8LOG_HEIGHT 8
uint8_t u8log_buffer[U8LOG_WIDTH*U8LOG_HEIGHT];
U8X8LOG u8x8log;
//OLED end
#include <ESP8266WiFi.h>
const char* APssid = "My_SSID"; //acess point of the device
const char* APpassword = "My_Password";
//const char* myconstcharstarstring = "------------------------------";
const int RSSI_MAX = -37;//maximum strength of signal in dBm
const int RSSI_MIN =-100;//minimum strength of signal in dBm
void setup()
{
//OLED
u8x8.begin();
u8x8.setFont(u8x8_font_chroma48medium8_r);
u8x8log.begin(u8x8, U8LOG_WIDTH, U8LOG_HEIGHT, u8log_buffer);
u8x8log.setRedrawMode(1); // 0: Update screen with newline, 1: Update screen for every char
//OLED end
WiFi.mode(WIFI_OFF);
WiFi.disconnect();
delay(50); //this part turns off the wifi and resets it if it was already on
Serial.begin(115200);
pinMode(LED_BUILTIN,OUTPUT);
Serial.println();
WiFi.mode(WIFI_AP_STA); //configuring the board in hybrid mode
Serial.print("Configuring access point...");
WiFi.softAP(APssid, APpassword);
Serial.println(WiFi.softAPIP());
}
void loop()
{
digitalWrite(LED_BUILTIN,LOW);
Serial.println("Wifi is scanning");
int n = WiFi.scanNetworks();
Serial.println("Wifi scan ended");
if (n == 0)
{
Serial.println("no networks found");
}
else
{
Serial.print(n);
Serial.println(" networks found");
for (int i = 0; i < n; ++i)
{
//Print SSID and RSSI for each network found
Serial.print(i + 1);
Serial.print(") ");
Serial.print(WiFi.SSID(i));//SSID
Serial.print(WiFi.RSSI(i));//Signal strength in dBm
Serial.print("dBm (");
if(WiFi.RSSI(i) > -37)//THIS -37 (RSSI) is the threshold value, this value is set according to the distance of 1m
{
digitalWrite(LED_BUILTIN,HIGH);//(Generic esp8266 : (14,HIGH) , NodeMCU : (D5,HIGH) )
Serial.println("Social Distancing");
delay(500);
}
//OLED
u8x8log.print(WiFi.SSID(i));
u8x8log.print("\n");
u8x8log.print(WiFi.RSSI(i));
u8x8log.print("\n");
u8x8log.print("-------------");
u8x8log.print("\n");
delay(2000);
}
Serial.println("");
delay(50);
WiFi.scanDelete();
}
}
Hope this answers All the best

Answer 2

Hi Lisa please add digitalWrite(14,HIGH); at the beginning of the loop, it will work:
void loop()
{
digitalWrite(14,HIGH);
/... rest of your code...
I don't know how you have wired your buzzer, try forcing your ouput pin HIGH or LOW depending on your circuit.
Hope this helps All the best