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User avatar
By Iisfaq
#22540 Here is some debug data from a little power monitor I created. It reads from the ADC pin and calculates power used with the help of a ACS712 current sensor.

But I have noticed that the following occurs

Connect TO WIFI
After 3 seconds it disconnects
After about 6 seconds it says there is no access point

Then next time it comes to upload I reconnect (since it is not connected) and the same thing happens time and time again.

Connecting to CROWE
......
WiFi connected
IP address:
192.168.2.128
Interval=1, WiFi.status=WL_CONNECTED=3
Interval=2, WiFi.status=WL_CONNECTED=3
Interval=3, WiFi.status=WL_CONNECTED=3
Interval=4, WiFi.status=WL_CONNECTED=3
Interval=5, WiFi.status=WL_DISCONNECTED=6
Interval=6, WiFi.status=WL_DISCONNECTED=6
Interval=7, WiFi.status=WL_DISCONNECTED=6
Interval=8, WiFi.status=WL_DISCONNECTED=6
Interval=9, WiFi.status=WL_DISCONNECTED=6
Interval=10, WiFi.status=WL_DISCONNECTED=6
Interval=11, WiFi.status=WL_DISCONNECTED=6
Interval=12, WiFi.status=WL_NO_SSID_AVAIL=1
Interval=13, WiFi.status=WL_NO_SSID_AVAIL=1
Interval=14, WiFi.status=WL_NO_SSID_AVAIL=1
Interval=15, WiFi.status=WL_NO_SSID_AVAIL=1
Interval=16, WiFi.status=WL_NO_SSID_AVAIL=1
Interval=17, WiFi.status=WL_NO_SSID_AVAIL=1
Interval=18, WiFi.status=WL_NO_SSID_AVAIL=1

The code is very simple as I have removed other stuff except WIFI

Code: Select all#include <ESP8266WiFi.h>

const char* ssid     = "CROWE";
const char* password = "abcd";

const char* host = "192.168.2.122";

String Statuses[] =  { "WL_IDLE_STATUS=0", "WL_NO_SSID_AVAIL=1", "WL_SCAN_COMPLETED=2", "WL_CONNECTED=3", "WL_CONNECT_FAILED=4", "WL_CONNECTION_LOST=5", "WL_DISCONNECTED=6"};
unsigned long lastMillis = 0;
unsigned long lastMillis2 = 0;
int IntervalInSeconds = 1;
int Errors = 0;
int min = 1024;
int max = -1024;
int samples = 0;
void setup() {

  Serial.begin(115200);
  Serial.println("ESP8266 Power Monitor");

  WiFi.mode(WIFI_STA);
  WiFi.disconnect();

  Connect();
}

void Connect()
{
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  int Attempt = 0;
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Attempt++;
    Serial.print(".");
    if (Attempt == 50)
    {
      Serial.println();
      Serial.println("Could not connect to WIFI");
      return;
    }
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop()
{
  yield() ; // Allow WIFI to do stuff

  unsigned long CurrentMillis = millis();
  if (CurrentMillis - lastMillis2 > 3)
  {
    lastMillis2 = CurrentMillis;

    double sensorValue = 0;
    for (int reading = 0; reading < 5; reading++)
    {
      sensorValue += analogRead(A0);
    }
    sensorValue /= 5;
    if ((int)sensorValue < min)
      min = (int)sensorValue;
    if ((int)sensorValue > max)
      max = (int)sensorValue;
    samples++;
  }

  if (CurrentMillis - lastMillis > 900)
  {
    lastMillis = CurrentMillis;

    Serial.print("Interval=");
    Serial.print(IntervalInSeconds);
    Serial.print(", WiFi.status=");
    Serial.print(Statuses[WiFi.status()]);

    if (IntervalInSeconds >= 60)
    {
      IntervalInSeconds = 1;

      Serial.print("connecting to ");
      Serial.println(host);

      if (WiFi.status() != WL_CONNECTED)
        Connect();

      if (WiFi.status() == WL_CONNECTED)
      {
        // Use WiFiClient class to create TCP connections
        WiFiClient client;
        const int httpPort = 8080;
        if (!client.connect(host, httpPort)) {
          Serial.println("connection failed");
          return;
        }

        // We now create a URI for the request
        String url = "/Power/?Watts=";
        url += "SOMENUMBER";
        url += "&DeviceID=HomeTheatre";

        Serial.print("Requesting URL: ");
        Serial.println(url);

        // This will send the request to the server
        client.print(String("GET ") + url + " HTTP/1.1\r\n" +
                     "Host: " + host + "\r\n" +
                     "Connection: close\r\n\r\n");
        delay(50);

        // Read all the lines of the reply from server and print them to Serial
        while (client.available()) {
          String line = client.readStringUntil('\r');
          Serial.print(line);
        }
        Serial.println();
      }
      else
      {
        Serial.print("Error Not Connected To WIFI, Error Count: ");
        Serial.println(++Errors);
      }
    }
    else
      Serial.println();

    IntervalInSeconds = IntervalInSeconds + 1;
    min = 1024;
    max = -1024;
    samples = 0;
  }
}



Now I have found two things:

1) The analogRead() is buggy in the current release of the Arduino IDE and I have modified the code for analogRead as per the discussion at the following:

https://github.com/esp8266/Arduino/issues/338

The code I changed it to was this

core_esp8266_wiring_analog.c in the folder C:\Users\ccrowe.AP\AppData\Roaming\Arduino15\packages\esp8266\hardware\esp8266\1.6.4-673-g8cd3697\cores\esp8266

Code: Select allextern int __analogRead(uint8_t pin) {
   if (pin == 17){
      return 0xffff & system_adc_read();
   }
   return digitalRead(pin) * 1023;
}


This code change fixed the issue with reading erroneous values from the ADC.

But if I comment out the analogRead() in my script the wifi does not disconnect, it stays connected.

So either there is a problem with the system_adc_read() function or something else is going on....

Chris
User avatar
By Iisfaq
#22743 Is this a limitation of the esp8266 chip? or the firmware on the chip?

If so it sort of makes esp8266 a bit limited for a lot of cases where one would want to use it.

Are there any other issues like this with the esp8266?

Would using a separate ADC chip over SPI work more reliably?

Chris