Not able to read analog port when using the autoconnect example

Question

Not able to read analog port when using the autoconnect example

MauPoLom opened this issue 4 years ago · comments

Hello,

Sorry to bother you with probably a beginners mistake and thank you for creating such a great library.

Issue is the following:
When I compile and run the autoconnect.ino, things run smoothly.

When I'm adding the simple code to read an analog pin (eg pin 12) it always returns 4095. I understand that when the pin is not connected this value should fluctuate but it stays constant.

I'll attach the example.
I'm using an esp32-wroom-32d on max osx

Thank you for your respond

Maurice

org_autoconnect2.txt

Khoi Hoang · Answer 1 · Wed Oct 21 2020 02:27:29 GMT+0800 (China Standard Time)

@MaPoLom

Thanks for using the library, your nice words and reporting the very rare and interesting bug.

I trace the bug out, and this is actually the bug of ESP32 MultiWiFi. The ESP8266 MultiWiFi has no issue with analogRead.

I'll continue to:

narrow down to pinpoint the bug locates where in the ESP32 MultiWiFi code.
check if the normal ESP32 WiFi interfering with the analogRead.

If the ESP32 WiFI code is OK with analogRead, I think I'll rewrite the ESP_WiFiManager as well as ESPAsync_WiFiManager library to get rid of ESP32 MultiWiFi code and use the regular ESP32 WiFi.

You can use the following code to check and verify

#if !( ESP32 || ESP8266 )
  #error This code is intended to run on the ESP32/ESP8266 platform! Please check your Tools->Board setting.
#endif

#define USE_MULTI_WIFI      true

#if ESP32
  #include <WiFi.h>
  #include <WiFiMulti.h>

  WiFiMulti wifiMulti;
#elif ESP8266
  #include <ESP8266WiFi.h>
  #include <ESP8266WiFiMulti.h>

  ESP8266WiFiMulti wifiMulti;
#endif

#define SSID_MAX_LEN      32
#define PASS_MAX_LEN      64

typedef struct
{
  char ssid[SSID_MAX_LEN + 1];
  char pass[PASS_MAX_LEN + 1];
}  WiFi_Credentials;

WiFi_Credentials WiFi_Creds[] =
{
  { "HueNet1", "12345678"},
  { "HueNet2", "12345678"},
  { "HueNet3", "12345678"}
};

#define NUMBER_SSIDS    ( sizeof(WiFi_Creds) / sizeof(WiFi_Credentials) )

uint8_t status;

int sensorPin   = 12; //A0;     // select the input pin for the potentiometer
int sensorValue = 0;             // variable to store the value coming from the sensor

uint8_t connectMultiWiFi(void)
{
  Serial.println("\nConnecting Wifi...");

  int i = 0;
  status = wifiMulti.run();
  delay(3000);

  while ( ( i++ < 10 ) && ( status != WL_CONNECTED ) )
  {
    status = wifiMulti.run();

    if ( status == WL_CONNECTED )
      break;
    else
      delay(3000);
  }

  if ( status == WL_CONNECTED )
  {
    Serial.println("WiFi connected to after " + String(i) + " times.");
    Serial.println("SSID = " + WiFi.SSID());
    Serial.println("RSSI = " + String(WiFi.RSSI()));
    Serial.println("Channel: " + String(WiFi.channel()));
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  }
  else
    Serial.println("WiFi not connected");

  return status;
}

void check_WiFi(void)
{
  if ( (WiFi.status() != WL_CONNECTED) )
  {
    Serial.println("\nWiFi lost. Call connectMultiWiFi in loop");
    connectMultiWiFi();
  }
}

void readAnalog(void)
{
  //----- start custom code
  sensorValue = analogRead(sensorPin);
  Serial.print("Pin " + String(sensorPin) + " = ");
  Serial.println(sensorValue);
  //---- end custom code
}

void check_status(void)
{
  static ulong checkstatus_timeout  = 0;
  static ulong checkwifi_timeout    = 0;

  static ulong current_millis;

#define WIFICHECK_INTERVAL    1000L
#define ANALOGREAD_INTERVAL   2000L

  current_millis = millis();

#if USE_MULTI_WIFI
  // Check WiFi every WIFICHECK_INTERVAL (1) seconds.
  if ((current_millis > checkwifi_timeout) || (checkwifi_timeout == 0))
  {
    check_WiFi();
    checkwifi_timeout = current_millis + WIFICHECK_INTERVAL;
  }
#endif

  // Print hearbeat every ANALOGREAD_INTERVAL (2) seconds.
  if ((current_millis > checkstatus_timeout) || (checkstatus_timeout == 0))
  {
    readAnalog();
    checkstatus_timeout = current_millis + ANALOGREAD_INTERVAL;
  }
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  while (!Serial);

  delay(200);

  Serial.print("\nStarting WiFiMulti_ESP32_AnalogRead on ");
  Serial.println(ARDUINO_BOARD);

#if USE_MULTI_WIFI
  for (int i = 0; i < NUMBER_SSIDS; i++)
  {
    wifiMulti.addAP(WiFi_Creds[i].ssid, WiFi_Creds[i].pass);
  }

  connectMultiWiFi();
#endif
  
}

void loop()
{
  // put your main code here, to run repeatedly
  check_status();
}

and this is the terminal output

1. No MultiWiFi by using `#define USE_MULTI_WIFI false`

Starting WiFiMulti_ESP32_AnalogRead on ESP32_DEV
Pin 12 = 104                         <=== Pin 12 to GND and analogRead responds
Pin 12 = 89
Pin 12 = 8
Pin 12 = 0
Pin 12 = 4095                      <=== Pin 12 to 3.3V and analogRead responds
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 64                           <=== Pin 12 to GND and analogRead responds
Pin 12 = 82
Pin 12 = 27
Pin 12 = 10
Pin 12 = 64
Pin 12 = 12

2. With MultiWiFi by using `#define USE_MULTI_WIFI true`

Starting WiFiMulti_ESP32_AnalogRead on ESP32_DEV

Connecting Wifi...
WiFi connected to after 1 times.
SSID = HueNet1
RSSI = -33
Channel: 2
IP address: 192.168.2.164
Pin 12 = 4095                            <=== Pin 12 to GND but analogRead is always 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095
Pin 12 = 4095

Khoi Hoang · Answer 2 · Wed Oct 21 2020 03:08:44 GMT+0800 (China Standard Time)

Extremely bad news is that the normal ESP32 WiFi is also interfering with analogRead

So no way to get out, at least now until the ESP32 bug is found and fixed.

ESP8266 is always OK. If possible, you can switch your project to

use ESP8266.
use ESP32 but external analog input/output module.

Use the following simple sketch to test and verify

#if !( ESP32 || ESP8266 )
  #error This code is intended to run on the ESP32/ESP8266 platform! Please check your Tools->Board setting.
#endif

#define USE_WIFI      false

#if ESP32
#include <WiFi.h>

int sensorPin   = 27; //12;     // select the input pin for the potentiometer
#elif ESP8266
#include <ESP8266WiFi.h>

int sensorPin   = 12; //A0;     // select the input pin for the potentiometer
#endif

#define SSID_MAX_LEN      32
#define PASS_MAX_LEN      64

typedef struct
{
  char ssid[SSID_MAX_LEN + 1];
  char pass[PASS_MAX_LEN + 1];
}  WiFi_Credentials;

WiFi_Credentials WiFi_Creds[] =
{
  { "HueNet1", "12345678"},
  { "HueNet2", "12345678"},
  { "HueNet3", "12345678"}
};

#define NUMBER_SSIDS    ( sizeof(WiFi_Creds) / sizeof(WiFi_Credentials) )

uint8_t status;


int sensorValue = 0;            // variable to store the value coming from the sensor

uint8_t connectWiFi(void)
{
  Serial.println("\nConnecting Wifi...");

  int i = 0;

  WiFi.begin(WiFi_Creds[0].ssid, WiFi_Creds[0].pass);
  
  status = WiFi.status();
  delay(3000);

  while ( ( i++ < 10 ) && ( status != WL_CONNECTED ) )
  {
    status = WiFi.status();

    if ( status == WL_CONNECTED )
      break;
    else
      delay(3000);
  }

  if ( status == WL_CONNECTED )
  {
    Serial.println("WiFi connected to after " + String(i) + " times.");
    Serial.println("SSID = " + WiFi.SSID());
    Serial.println("RSSI = " + String(WiFi.RSSI()));
    Serial.println("Channel: " + String(WiFi.channel()));
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  }
  else
    Serial.println("WiFi not connected");

  return status;
}

void check_WiFi(void)
{
  if ( (WiFi.status() != WL_CONNECTED) )
  {
    Serial.println("\nWiFi lost. Call connectMultiWiFi in loop");
    connectWiFi();
  }
}

void readAnalog(void)
{
  //----- start custom code
  sensorValue = analogRead(sensorPin);
  Serial.print("Pin " + String(sensorPin) + " = ");
  Serial.println(sensorValue);
  //---- end custom code
}

void check_status(void)
{
  static ulong checkstatus_timeout  = 0;
  static ulong checkwifi_timeout    = 0;

  static ulong current_millis;

#define WIFICHECK_INTERVAL    1000L
#define ANALOGREAD_INTERVAL   2000L

  current_millis = millis();

#if USE_WIFI
  // Check WiFi every WIFICHECK_INTERVAL (1) seconds.
  if ((current_millis > checkwifi_timeout) || (checkwifi_timeout == 0))
  {
    check_WiFi();
    checkwifi_timeout = current_millis + WIFICHECK_INTERVAL;
  }
#endif

  // Print hearbeat every ANALOGREAD_INTERVAL (2) seconds.
  if ((current_millis > checkstatus_timeout) || (checkstatus_timeout == 0))
  {
    readAnalog();
    checkstatus_timeout = current_millis + ANALOGREAD_INTERVAL;
  }
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  while (!Serial);

  delay(200);

  Serial.print("\nStarting WiFi_ESP32_AnalogRead on ");
  Serial.println(ARDUINO_BOARD);

#if USE_WIFI
  connectWiFi();
#endif

}

void loop()
{
  // put your main code here, to run repeatedly
  check_status();
}

and this is the terminal output

1. No WiFi by using `#define USE_WIFI false`

Starting WiFi_ESP32_AnalogRead on ESP32_DEV
Pin 27 = 34                        <=== Pin 27 to GND and analogRead responds
Pin 27 = 4
Pin 27 = 26
Pin 27 = 4095                   <=== Pin 27 to 3.3V and analogRead responds
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 96                     <=== Pin 27 to GND and analogRead responds
Pin 27 = 120
Pin 27 = 96
Pin 27 = 0
Pin 27 = 0
Pin 27 = 0
Pin 27 = 21
Pin 27 = 25
Pin 27 = 64
Pin 27 = 64

2. With WiFi by using `#define USE_WIFI true`

Starting WiFi_ESP32_AnalogRead on ESP32_DEV

Connecting Wifi...
WiFi connected to after 1 times.
SSID = HueNet1
RSSI = -38
Channel: 2
IP address: 192.168.2.164
Pin 27 = 4095        <=== Pin 27 to GND but analogRead is always 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095
Pin 27 = 4095

So, I don't think it's necessary to do anything to the ESP_WiFiManager as well as ESPAsync_WiFiManager library.

As this is not the ESP_WiFiManager's bug, I'll close the issue after a while, but still keep you updated on the bug (where, how to fix, etc.).

Khoi Hoang · Answer 3 · Wed Oct 21 2020 07:26:00 GMT+0800 (China Standard Time)

OK, I find out the root cause of this issue as follows

1. ESP32 has 2 ADCs, named ADC1 and ADC2

2. ESP32 ADCs functions

ADC1 controls ADC function for pins GPIO32-GPIO39
ADC2 controls ADC function for pins GPIO0, 2, 4, 12, 13, 14, 15, 25, 26 and 27

3.. ESP32 WiFi uses ADC2 for WiFi functions

in order to use ADC2 for other functions, we have to acquire complicated firmware locks and very difficult to do
It's not advisable to use ADC2 with WiFi

See in file adc_common.c

In ADC2, there're two locks used for different cases:

lock shared with app and Wi-Fi:
ESP32:
When Wi-Fi using the ADC2, we assume it will never stop, so app checks the lock and returns immediately if failed.
ESP32S2:
The controller's control over the ADC is determined by the arbiter. There is no need to control by lock.

lock shared between tasks:
when several tasks sharing the ADC2, we want to guarantee
all the requests will be handled.
Since conversions are short (about 31us), app returns the lock very soon,
we use a spinlock to stand there waiting to do conversions one by one.

adc2_spinlock should be acquired first, then adc2_wifi_lock or rtc_spinlock.

So I suggest to use ADC1, and pins GPIO32-GPIO39

Use the following simple sketch to test and verify

#if !( ESP32 || ESP8266 )
  #error This code is intended to run on the ESP32/ESP8266 platform! Please check your Tools->Board setting.
#endif

#define USE_MULTI_WIFI      false

#if ESP32
  #include <WiFi.h>
  #include <WiFiMulti.h>

  WiFiMulti wifiMulti;

  int sensorPin1   = 34;     // select the input pin for the potentiometer
  int sensorPin2   = 35;     // select the input pin for the potentiometer
#elif ESP8266
  #include <ESP8266WiFi.h>
  #include <ESP8266WiFiMulti.h>

  ESP8266WiFiMulti wifiMulti;
  
  int sensorPin1    = 12;     // select the input pin for the potentiometer
  int sensorPin2    = 13;     // select the input pin for the potentiometer
#endif

#define SSID_MAX_LEN      32
#define PASS_MAX_LEN      64

typedef struct
{
  char ssid[SSID_MAX_LEN + 1];
  char pass[PASS_MAX_LEN + 1];
}  WiFi_Credentials;

WiFi_Credentials WiFi_Creds[] =
{
  { "HueNet1", "12345678"},
  { "HueNet2", "12345678"},
  { "HueNet3", "12345678"}
};

#define NUMBER_SSIDS    ( sizeof(WiFi_Creds) / sizeof(WiFi_Credentials) )

uint8_t status;


int sensorValue = 0;            // variable to store the value coming from the sensor

uint8_t connectMultiWiFi(void)
{
  Serial.println("\nConnecting Wifi...");

  int i = 0;
  status = wifiMulti.run();
  delay(3000);

  while ( ( i++ < 10 ) && ( status != WL_CONNECTED ) )
  {
    status = wifiMulti.run();

    if ( status == WL_CONNECTED )
      break;
    else
      delay(3000);
  }

  if ( status == WL_CONNECTED )
  {
    Serial.println("WiFi connected to after " + String(i) + " times.");
    Serial.println("SSID = " + WiFi.SSID());
    Serial.println("RSSI = " + String(WiFi.RSSI()));
    Serial.println("Channel: " + String(WiFi.channel()));
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  }
  else
    Serial.println("WiFi not connected");

  return status;
}

void check_WiFi(void)
{
  if ( (WiFi.status() != WL_CONNECTED) )
  {
    Serial.println("\nWiFi lost. Call connectMultiWiFi in loop");
    connectMultiWiFi();
  }
}

void readAnalog(void)
{
  sensorValue = analogRead(sensorPin1);
  Serial.print("Pin " + String(sensorPin1) + " = ");
  Serial.println(sensorValue);

  sensorValue = analogRead(sensorPin2);
  Serial.print("Pin " + String(sensorPin2) + " = ");
  Serial.println(sensorValue);
}

void check_status(void)
{
  static ulong checkstatus_timeout  = 0;
  static ulong checkwifi_timeout    = 0;

  static ulong current_millis;

#define WIFICHECK_INTERVAL    1000L
#define ANALOGREAD_INTERVAL   2000L

  current_millis = millis();

#if USE_MULTI_WIFI
  // Check WiFi every WIFICHECK_INTERVAL (1) seconds.
  if ((current_millis > checkwifi_timeout) || (checkwifi_timeout == 0))
  {
    //check_WiFi();
    checkwifi_timeout = current_millis + WIFICHECK_INTERVAL;
  }
#endif

  // Print hearbeat every ANALOGREAD_INTERVAL (2) seconds.
  if ((current_millis > checkstatus_timeout) || (checkstatus_timeout == 0))
  {
    readAnalog();
    checkstatus_timeout = current_millis + ANALOGREAD_INTERVAL;
  }
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  while (!Serial);

  delay(200);

  Serial.print("\nStarting WiFiMulti_ESP32_AnalogRead on ");
  Serial.println(ARDUINO_BOARD);

#if USE_MULTI_WIFI
  for (int i = 0; i < NUMBER_SSIDS; i++)
  {
    wifiMulti.addAP(WiFi_Creds[i].ssid, WiFi_Creds[i].pass);
  }

  connectMultiWiFi();
#endif
  
}

void loop()
{
  // put your main code here, to run repeatedly
  check_status();
}

and this is the terminal output with analogRead value varies when pulled up, float or pulled down

Starting WiFiMulti_ESP32_AnalogRead on ESP32_DEV
Connecting Wifi...
WiFi connected to after 1 times.
SSID = HueNet1
RSSI = -39
Channel: 2
IP address: 192.168.2.164
Pin 34 = 0
Pin 35 = 0
Pin 34 = 0
Pin 35 = 0
Pin 34 = 0
Pin 35 = 1460
Pin 34 = 0
Pin 35 = 4095
Pin 34 = 0
Pin 35 = 0
Pin 34 = 0
Pin 35 = 0
Pin 34 = 0
Pin 35 = 0
Pin 34 = 4095
Pin 35 = 0
Pin 34 = 849
Pin 35 = 0
Pin 34 = 2175
Pin 35 = 0
Pin 34 = 4095
Pin 35 = 0
Pin 34 = 4016
Pin 35 = 0
Pin 34 = 3681
Pin 35 = 0
Pin 34 = 4095
Pin 35 = 0
Pin 34 = 3831
Pin 35 = 0
Pin 34 = 0
Pin 35 = 0

Again thanks for your report of this very interesting hidden issue.. And be confident as you're not beginner as you think.

Issue closed now. Good luck with ESP32.

Khoi Hoang · Answer 4 · Wed Oct 21 2020 08:39:59 GMT+0800 (China Standard Time)

@MaPoLom

If somehow you must use those pins serviced by ADC2 (GPIO0, 2, 4, 12, 13, 14, 15, 25, 26 and 27), use the following fix to work with ESP32 WiFi

#if !( ESP32 || ESP8266 )
  #error This code is intended to run on the ESP32/ESP8266 platform! Please check your Tools->Board setting.
#endif

#define USE_MULTI_WIFI      true

#if ESP32
  #include <WiFi.h>
  #include <WiFiMulti.h>

  WiFiMulti wifiMulti;

  #define USE_ADC2      true
  //#define USE_ADC2      false

  #if USE_ADC2
    // ADC2 for GPIO0, 2, 4, 12, 13, 14, 15, 25, 26 and 27
    int sensorPin1   = 12;
    int sensorPin2   = 14;  
  #else
    // DC1 for GPIO032-GPIO39
    int sensorPin1   = 34;
    int sensorPin2   = 35;
  #endif
  
  // Kludge to fix ADC2 + WiFi
  #include "soc/sens_reg.h"    // needed for manipulating ADC2 control register
  uint64_t reg_b;             // Used to store ADC2 control register
  //////
  
#elif ESP8266
  #include <ESP8266WiFi.h>
  #include <ESP8266WiFiMulti.h>

  ESP8266WiFiMulti wifiMulti;
  
  int sensorPin1    = 12;     // select the input pin for the potentiometer
  int sensorPin2    = 13;     // select the input pin for the potentiometer
#endif

#define SSID_MAX_LEN      32
#define PASS_MAX_LEN      64

typedef struct
{
  char ssid[SSID_MAX_LEN + 1];
  char pass[PASS_MAX_LEN + 1];
}  WiFi_Credentials;

WiFi_Credentials WiFi_Creds[] =
{
  { "HueNet1", "12345678"},
  { "HueNet2", "12345678"},
  { "HueNet3", "12345678"}
};

#define NUMBER_SSIDS    ( sizeof(WiFi_Creds) / sizeof(WiFi_Credentials) )

uint8_t status;


int sensorValue = 0;            // variable to store the value coming from the sensor

uint8_t connectMultiWiFi(void)
{
  Serial.println("\nConnecting Wifi...");

  int i = 0;
  status = wifiMulti.run();
  delay(3000);

  while ( ( i++ < 10 ) && ( status != WL_CONNECTED ) )
  {
    status = wifiMulti.run();

    if ( status == WL_CONNECTED )
      break;
    else
      delay(3000);
  }

  if ( status == WL_CONNECTED )
  {
    Serial.println("WiFi connected to after " + String(i) + " times.");
    Serial.println("SSID = " + WiFi.SSID());
    Serial.println("RSSI = " + String(WiFi.RSSI()));
    Serial.println("Channel: " + String(WiFi.channel()));
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  }
  else
    Serial.println("WiFi not connected");

  return status;
}

void check_WiFi(void)
{
  if ( (WiFi.status() != WL_CONNECTED) )
  {
    Serial.println("\nWiFi lost. Call connectMultiWiFi in loop");
    connectMultiWiFi();
  }
}

#if (ESP32 && USE_ADC2)
void save_ADC_Reg(void)
{
  // Save ADC2 control register value : Do this before begin Wifi/Bluetooth
  reg_b = READ_PERI_REG(SENS_SAR_READ_CTRL2_REG);
}

void restore_ADC_Reg(void)
{
  // ADC2 control register restoring 
  WRITE_PERI_REG(SENS_SAR_READ_CTRL2_REG, reg_b);
  SET_PERI_REG_MASK(SENS_SAR_READ_CTRL2_REG, SENS_SAR2_DATA_INV);
}
#endif

void readAnalog(void)
{
#if (ESP32 && USE_ADC2) 
  restore_ADC_Reg();
#endif
  
  sensorValue = analogRead(sensorPin1);
  Serial.print("Pin " + String(sensorPin1) + " = ");
  Serial.println(sensorValue);

  sensorValue = analogRead(sensorPin2);
  Serial.print("Pin " + String(sensorPin2) + " = ");
  Serial.println(sensorValue);
}

void check_status(void)
{
  static ulong checkstatus_timeout  = 0;
  static ulong checkwifi_timeout    = 0;

  static ulong current_millis;

#define WIFICHECK_INTERVAL    1000L
#define ANALOGREAD_INTERVAL   2000L

  current_millis = millis();

#if USE_MULTI_WIFI
  // Check WiFi every WIFICHECK_INTERVAL (1) seconds.
  if ((current_millis > checkwifi_timeout) || (checkwifi_timeout == 0))
  {
    //check_WiFi();
    checkwifi_timeout = current_millis + WIFICHECK_INTERVAL;
  }
#endif

  // Print hearbeat every ANALOGREAD_INTERVAL (2) seconds.
  if ((current_millis > checkstatus_timeout) || (checkstatus_timeout == 0))
  {
    readAnalog();
    checkstatus_timeout = current_millis + ANALOGREAD_INTERVAL;
  }
}

void setup()
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  while (!Serial);

  delay(200);

  Serial.print("\nStarting WiFiMulti_ESP32_AnalogRead on ");
  Serial.println(ARDUINO_BOARD);

#if (ESP32 && USE_ADC2)
  save_ADC_Reg();
#endif  

#if USE_MULTI_WIFI
  for (int i = 0; i < NUMBER_SSIDS; i++)
  {
    wifiMulti.addAP(WiFi_Creds[i].ssid, WiFi_Creds[i].pass);
  }

  connectMultiWiFi();
#endif
  
}

void loop()
{
  // put your main code here, to run repeatedly
  check_status();
}

and this is the terminal output when using in sketch

#define USE_ADC2 true

Starting WiFiMulti_ESP32_AnalogRead on ESP32_DEV

Connecting Wifi...
WiFi connected to after 1 times.
SSID = HueNet1
RSSI = -40
Channel: 2
IP address: 192.168.2.164
Pin 12 = 24
Pin 14 = 20
Pin 12 = 67
Pin 14 = 68
Pin 12 = 17
Pin 14 = 16
Pin 12 = 54
Pin 14 = 81
Pin 12 = 119
Pin 14 = 17
Pin 12 = 51
Pin 14 = 69
Pin 12 = 20
Pin 14 = 5
Pin 12 = 20
Pin 14 = 82
Pin 12 = 36
Pin 14 = 14
Pin 12 = 32
Pin 14 = 22
Pin 12 = 81
Pin 14 = 35
Pin 12 = 83
Pin 14 = 66
Pin 12 = 32
Pin 14 = 26
Pin 12 = 105
Pin 14 = 85
Pin 12 = 80
Pin 14 = 102
Pin 12 = 74

MauPolom · Answer 5 · Wed Oct 21 2020 15:43:56 GMT+0800 (China Standard Time)

Hi,

Thank you for your very, very thorough analysis. I'll need a few hours to digest this and choose the right path to follow.
There is no absolute need to use GPIO12 and/or 14 at this point (I thnik ;-) , so we can try to use ADC1.

Perhaps it's an idea, to make a reference to these findings in the readme?

Stay safe!

Maurice

Khoi Hoang · Answer 6 · Thu Oct 22 2020 02:22:54 GMT+0800 (China Standard Time)

Already updated README

Don't hesitate to post an issue next time. Valid or invalid, common or rare problem is always helpful to other people.

Khoi Hoang · Answer 7 · Tue Mar 30 2021 10:28:59 GMT+0800 (China Standard Time)

@tamer79

Although your issue has nothing to do with the library and it's not appropriate to hijack an issue, I just suggest you to read HOWTO Use analogRead() with ESP32 running WiFi and/or BlueTooth (BT/BLE)

There you'll see that pin 25-26 belong to ADC2 which won't work when you're using WiFi.

The obvious fix is to move the ADC pins from pins 25-26 to GPIO32-GPIO39 (for example 32-33).

Next time, after you have graduated and become a professional, please give back to the community and post in the correct forum.

Good Luck,

tamer79 · Answer 8 · Tue Mar 30 2021 10:45:29 GMT+0800 (China Standard Time)

I am very sorry. With my poor English, I understood that the subject was the same. I will delete the post. Thank you for the help anyway. Surely my intention was never to break any rule.

Khoi Hoang · Answer 9 · Tue Mar 30 2021 10:47:12 GMT+0800 (China Standard Time)

It's OK to keep it there, possibly to help other users. Don't delete it.

Not able to read analog port when using the autoconnect example

1. No MultiWiFi by using #define USE_MULTI_WIFI false

2. With MultiWiFi by using #define USE_MULTI_WIFI true

1. No WiFi by using #define USE_WIFI false

2. With WiFi by using #define USE_WIFI true

1. ESP32 has 2 ADCs, named ADC1 and ADC2

2. ESP32 ADCs functions

3.. ESP32 WiFi uses ADC2 for WiFi functions

1. No MultiWiFi by using `#define USE_MULTI_WIFI false`

2. With MultiWiFi by using `#define USE_MULTI_WIFI true`

1. No WiFi by using `#define USE_WIFI false`

2. With WiFi by using `#define USE_WIFI true`