Other Arduino Codes and Videos by Robojax

Using ESP8266 WiFi Scan with LCD1602-I2C to display strength in percentage with Arduino

دروس آردوینو به فارسی

Using ESP8266 WiFi Scan to display signal strength as dBm or Percentage with Arduino

This code is to use ESP8266, NodeMCU, Wemos D1 Mini to display all available access points (WiFi ) on LCD1602-I2C or LCD2004-I2C to display RSSI in dBM or Percentage

Resources for this sketch

• Wemos.cc official Websit of D1 Mini
• ESP8266 Arduino Driver on Gethub
• ESP8266 Datasheet (pdf)
• LCD1602 Library (from Robojax.com)
• LCD1602 Library (from GetHub)
• I2C Scanner code
• I2C Scanner
• Introduction to LCD1602-I2C with code
• Introduction Wemos NodeMCU
• Robojax Arduino Course on Udemy
• Get Early Access to my videos via Patreon

Basic WiFi scan code

/*
 * Display WiFi Access Point Signal Strength on LCD1602-I2C as dBm or Percentage with ESP8266  Arduino
 * Written by Ahmad Shamshiri on Aug 12, 2019
 * in Ajax, Ontario, Canada
 * for Robojax.com
 * Watch video instruction for this code: https://youtu.be/HYMnCUtNMnw
 * 
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*/
#include "ESP8266WiFi.h"
const int RSSI_MAX =-50;// define maximum strength of signal in dBm
const int RSSI_MIN =-100;// define minimum strength of signal in dBm


// start of settings for LCD1602 with I2C
#include <LiquidCrystal_I2C.h>
// Set the LCD address to 0x27 for a 16 chars and 2 line display
LiquidCrystal_I2C lcd(0x3F, 16, 2);
// end of settings for LCD1602 with I2C

int count =0;

int scanDelayTime = 1000;
int wiFiDisplayTime = 3000;

void setup() {
  // Set WiFi to station mode and 
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();//disconnect from an AP if it was previously connected
    
  lcd.begin();  
  lcd.backlight();
  lcd.print("Robojax ESP8266");
  lcd.setCursor(0,1);
  lcd.print("Wifi Scan Demo");  
  delay(2000); 
}


void loop() {
 // Robojax D1 Mini LCD-1602-I2C  WiFi Scan

// WiFi.scanNetworks will return the number of networks found
  int n = WiFi.scanNetworks();
  lcd.clear();// clear previous values from screen
  lcd.print("scan done");     
  if (n == 0) {
    lcd.print("No WiFI found");   
  } else {
    lcd.setCursor(0,1);
    lcd.print(n);
    lcd.print( " AP found");
    for (int i = 0; i < n; ++i) {

      // Print SSID and RSSI for each network found
      lcd.clear();// clear previous values from screen
      lcd.setCursor(0,0);
      lcd.print(i+1);      
      lcd.print(") "); 
      lcd.print(WiFi.SSID(i));     
      lcd.setCursor(0,1);        
      lcd.print("Signal: ");      
      lcd.print(dBmtoPercentage(WiFi.RSSI(i))); 
      lcd.print("%"); 
      delay(wiFiDisplayTime);
    }
  }  

  delay(scanDelayTime); 
}// loop end


/*
 * Written by Ahmad Shamshiri
  * with lots of research, this sources was used:
 * https://support.randomsolutions.nl/827069-Best-dBm-Values-for-Wifi 
 * This is approximate percentage calculation of RSSI
 * Wifi Signal Strength Calculation
 * Written Aug 08, 2019 at 21:45 in Ajax, Ontario, Canada
 */

int dBmtoPercentage(int dBm)
{
  int quality;
    if(dBm <= RSSI_MIN)
    {
        quality = 0;
    }
    else if(dBm >= RSSI_MAX)
    {  
        quality = 100;
    }
    else
    {
        quality = 2 * (dBm + 100);
   }

     return quality;
}//dBmtoPercentage
   

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