Can you use all the ESP32's GPIO pins when the WiFi is working?

I have a weird phenomenon that when I add the WiFi library and all the settings, 2 out of 3 sensors stop working. When I remove the WiFi code it works like it used to.

I have an ESP32 devkit v1 board and connected 3 sensors which are a photoresistor (ky-018), a dht-11, and a capacitive soil moisture sensor.

dht-11 is connected to D14 (works);
photoresistor(ky-018) connected to D13 (doesn't work);
capacitive soil moisture sensor connected to D15 (doesn't work).

I tried changing pins; didn't help.

Here is the code:

#include "DHT.h"
#include <WiFi.h>

#define DHTPIN 14       // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11   // DHT 11

const char* ssid = "Cgates_E031F1"; // ESP32 and ESP8266 uses 2.4GHZ wifi only
const char* password = "60E541C32F";

DHT dht(DHTPIN, DHTTYPE);
const byte lightPin = 13;
int lightReading;
int lightReadingpercent=0;
const int RELAY_PIN = 15;    // the Arduino pin, which connects to the IN pin of relay
const int AirValue = 4095;   //you need to replace this value with Value_1
const int WaterValue = 2200; //you need to replace this value with Value_2
const int SensorPin = 15;    // Soil moisture

int soilMoistureValue = 0;
int soilmoisturepercent=0;
const int Lightvalue = 0;
const int Darkvalue = 4095;
 

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);

  // begin Wifi connect
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  delay(2000);
  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
 
  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  //end Wifi connect
 
  pinMode(RELAY_PIN, OUTPUT);//relay
  
  Serial.println(F("DHTxx test!")); //dht
  ; 
  dht.begin();
}

void loop() {
  // put your main code here, to run repeatedly:

  lightReading = analogRead(lightPin); //0-4095 12bit -- esp8266 10bit 0-1023 -- arduino 8bit 0-254
 
  Serial.print("Light reading = ");
  
  lightReadingpercent = map(lightReading, Darkvalue, Lightvalue,  0, 100 );
  Serial.print(lightReadingpercent);
  Serial.println(" %");
  Serial.println();
  
  delay(500);

  soilMoistureValue = analogRead(SensorPin);  //put Sensor insert into soil 

  soilmoisturepercent = map(soilMoistureValue, AirValue, WaterValue, 0, 100);

  if (soilmoisturepercent > 100) {
    Serial.println("Soil moisture ");
    Serial.println("100 %");
    delay(500);
  } else if (soilmoisturepercent <0) {
    Serial.println("Soil moisture ");
    Serial.println("0 %");
    delay(500);
  } else if (soilmoisturepercent >=0 && soilmoisturepercent <= 100) {
    Serial.println("Soil moisture "); //go to next line
    Serial.print(soilmoisturepercent);
    Serial.println("%");
    delay(500); // soil end
  }
 
  // Wait a few seconds between measurements.
  delay(2000);

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }

  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  Serial.print(F(" Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.print(F("C "));
  Serial.print(f);
  Serial.print(F("F  Heat index: "));
  Serial.print(hic);
  Serial.print(F("C "));
  Serial.print(hif);
  Serial.println(F("F"));

  delay(500); //wait 0.5seconds
}

Solution

The problem is probably that, according to this comment on this issue on GitHub:

ADC2 pins can not be used when WiFi is used. On the other hand, ADC1 pins can be used even when WiFi is enabled.

This is probably because the ADC2 is used by the WiFi firmware running on the core that has the ADC2 peripheral.

This doesn't explain why GPIO14 is working for you, though, but still, you could try using only GPIO pins that use ADC1 and see if that works for you.

Also, WiFi can pull quite a bit of current; make sure the power supply is up to it, so you don't get voltage drops.