Kommunikation zwischen ESP8266 und Raspberry pi

Hallo Leute,

meine Agenda:
Ich hab ein esp8266 der von dem sds011 FeinstaubSensor Daten bekommt. Der esp8266 soll die Daten an einem Raspberry Pi Router verschicken, der wiederum diese Daten an einem anderen Raspberry Pi, welcher als Webserver eingerichtet wird, senden.
Also quasi:

SDS011+ESP8266 ->Daten-> Raspirouter->Daten->RaspiWebserver

Ich habe im Internet recherchiert und nichts konnte mein Verständnis helfen.
Welche Möglichkeiten gibt es?
Habt ihr da paar Denkanstöße?

vielen Dank!!

du könntest mit dem ESP8266 mittels HTTP Client an den RaspiWebserver senden.

IDE Beispiel ESP8266HTTPClient / PostHTTPClient.ino
am RaspiWebserver z.B. mittels PHP übernehmen

Hier habe ich mal ein paar Denkanstöße in 4 Teilen gegeben:
https://werner.rothschopf.net/202009_iot_webserver_intro.htm

Du könntest deine Daten auch per UDP weiter leiten.
Da findest du hier Beispiele zu.

Hier ist ein Demo-code der einern String per UDP sendet.
Auf dem Raspi läuft dann das Python-Script das am Ende in Blockkommentarklammern steht

// I wrote some basic documentation at the end of the file
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <PString.h>
#include <time.h>                   // time() ctime()

char *ssid     = "FRITZ!Box 7490";
char *password = "";

IPAddress    remoteIP     (192, 168, 178, 160); // receiver-IP
unsigned int remotePort = 4210;                 // receiver port to listen on must match the portnumber the receiver is listening to

WiFiUDP Udp;

const char* ntpServer = "fritz.box";
const long  gmtOffset_sec = 0;
const int   daylightOffset_sec = 7200;

#include <time.h>                   // time() ctime()
time_t now;                         // this is the epoch
tm myTimeInfo;                      // the structure tm holds time information in a more convient way


boolean TimePeriodIsOver (unsigned long &expireTime, unsigned long TimePeriod) {
  unsigned long currentMillis  = millis();
  if ( currentMillis - expireTime >= TimePeriod )
  {
    expireTime = currentMillis; // set new expireTime
    return true;                // more time than TimePeriod) has elapsed since last time if-condition was true
  }
  else return false;            // not expired
}

const byte OnBoard_LED = 2;
int BlinkTime = 500;

void BlinkHeartBeatLED(int IO_Pin, int BlinkPeriod) {
  static unsigned long MyBlinkTimer;
  pinMode(IO_Pin, OUTPUT);

  if ( TimePeriodIsOver(MyBlinkTimer, BlinkPeriod) ) {
    digitalWrite(IO_Pin, !digitalRead(IO_Pin) );
  }
}

unsigned long TestTimer;
unsigned long UDP_SendTimer;

int myCounter = 0;
int HeaderNr  = 0;
#define MaxMsgLength 1024
char  UDP_Msg_AoC[MaxMsgLength + 1]; // always remember one extra-char for terminating zero 
PString UDP_Msg_PS(UDP_Msg_AoC, sizeof(UDP_Msg_AoC));
uint8_t UDP_Msg_uint8_Buffer[MaxMsgLength + 1]; // for some strange reasons on ESP32 the udp.write-function needs an uint8_t-array

#define MaxHeaderLength 64 
char    Header_AoC[MaxHeaderLength + 1]; // always remember one extra-char for terminating zero 
PString Header_PS(Header_AoC, sizeof(Header_AoC));

#define MaxTimeStampLength 32 
char    TimeStamp_AoC[MaxTimeStampLength + 1]; // always remember one extra-char for terminating zero 
PString TimeStamp_PS(TimeStamp_AoC, sizeof(TimeStamp_AoC));

char HeaderDelimiter = '$'; // must match the delimiter defined in the python-code 


void PrintFileNameDateTime()
{
  Serial.print("Code running comes from file ");
  Serial.println(__FILE__);
  Serial.print(" compiled ");
  Serial.print(__DATE__);
  Serial.println(__TIME__);
}

void showTime() {
  time(&now);                       // read the current time
  localtime_r(&now, &myTimeInfo);           // update the structure tm with the current time
  Serial.print("year:");
  Serial.print(myTimeInfo.tm_year + 1900);  // years since 1900
  Serial.print("\tmonth:");
  Serial.print(myTimeInfo.tm_mon + 1);      // January = 0 (!)
  Serial.print("\tday:");
  Serial.print(myTimeInfo.tm_mday);         // day of month
  Serial.print("\thour:");
  Serial.print(myTimeInfo.tm_hour);         // hours since midnight  0-23
  Serial.print("\tmin:");
  Serial.print(myTimeInfo.tm_min);          // minutes after the hour  0-59
  Serial.print("\tsec:");
  Serial.print(myTimeInfo.tm_sec);          // seconds after the minute  0-61*
  Serial.print("\twday");
  Serial.print(myTimeInfo.tm_wday);         // days since Sunday 0-6
  if (myTimeInfo.tm_isdst == 1)             // Daylight Saving Time flag
    Serial.print("\tDST");
  else
    Serial.print("\tstandard");
    
  Serial.println();
}

// my personal naming-convention parameter of functions start with prefix "p_"
void StoreTimeStampStr(char* p_PointerToTarget, tm p_myTimeInfo) {

char    l_TimeStamp_AoC[MaxTimeStampLength + 1]; // always remember one extra-char for terminating zero 
PString l_TimeStamp_PS(l_TimeStamp_AoC, sizeof(l_TimeStamp_AoC));

  time(&now);                       // read the current time
  localtime_r(&now, &myTimeInfo);

  l_TimeStamp_PS  = p_myTimeInfo.tm_year + 1900;
  l_TimeStamp_PS += ".";
  l_TimeStamp_PS += p_myTimeInfo.tm_mon + 1;
  l_TimeStamp_PS += ".";
  l_TimeStamp_PS += p_myTimeInfo.tm_mday;

  l_TimeStamp_PS += ", ";
  l_TimeStamp_PS += p_myTimeInfo.tm_hour;
  l_TimeStamp_PS += ":";
  l_TimeStamp_PS += p_myTimeInfo.tm_min;
  l_TimeStamp_PS += ":";
  l_TimeStamp_PS += p_myTimeInfo.tm_sec;
  l_TimeStamp_PS += ",";  

  strlcpy(p_PointerToTarget, l_TimeStamp_AoC,l_TimeStamp_PS.length() + 1);
}


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

  WiFi.persistent(false);
  WiFi.mode(WIFI_STA);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    BlinkHeartBeatLED(OnBoard_LED, 333);
    delay(332);
    Serial.print(".");
  }
  Serial.print("\n connected.");
  Serial.println(WiFi.localIP() );

}

void synchroniseWith_NTP_Time() {
  Serial.print("configTime uses ntpServer ");
  Serial.println(ntpServer);
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
  Serial.print("synchronising time");
  
  while (myTimeInfo.tm_year + 1900 < 2000 ) {
    time(&now);                       // read the current time
    localtime_r(&now, &myTimeInfo);
    BlinkHeartBeatLED(OnBoard_LED, 100);
    delay(100);
    Serial.print(".");
  }
  Serial.print("\n time synchronsized \n");
  showTime();    
}

void setup() {
  Serial.begin(115200);
  Serial.println("\n Setup-Start \n");
  PrintFileNameDateTime();
  connectToWifi();
  synchroniseWith_NTP_Time();
  Header_PS = "myDemoHeader"; 
}

void PrintMsg() {
  Serial.print("UDP_Msg_PS #");
  Serial.print(UDP_Msg_PS);
  Serial.println("#");
}

void loop() {
  BlinkHeartBeatLED(OnBoard_LED, BlinkTime);

  if (TimePeriodIsOver(UDP_SendTimer, 2000) ) {
    Serial.print("Send Message to #");
    Serial.print(remoteIP);
    Serial.print(":");
    Serial.println(remotePort);
    
    UDP_Msg_PS = Header_PS;
    UDP_Msg_PS += HeaderDelimiter;
    UDP_Msg_PS += "myUserData, ";
    StoreTimeStampStr(TimeStamp_AoC,myTimeInfo);
    UDP_Msg_PS += TimeStamp_PS;
    UDP_Msg_PS += myCounter++; 

    Serial.print("Send UDP_Msg #");
    Serial.print(UDP_Msg_PS);
    Serial.println("#");

    memcpy(UDP_Msg_uint8_Buffer,UDP_Msg_PS,UDP_Msg_PS.length()); // for some strange reason the ESP32 UDP-function write needs an uint8_t-array
    Udp.beginPacket(remoteIP, remotePort);
    Udp.write(UDP_Msg_uint8_Buffer, UDP_Msg_PS.length() );
    Udp.endPacket();
  }    
}

/*

This is a democode that demonstrates how to send TCP/UDP-messages with a timestamp 
The time is synchronized using a NTP-server. Most local routers like Fritz!Box can be used as the NTP-timer-server

The message has a userdefinable header which could be used for identifying the sender on the recieverside
There is a user-definable Header-delimiter that can be used to identify which characters of the
UDP-message belong to the header and which to the userdata

The code makes use of the PString-library. PStrings don't cause memory-problems like datatype "Strings"
and are easier to use than arrays of char. Example adding an integer to a PString-variable is as easy as
MyPString = myInteger;

The userdata has commas between each data so you can import the textfile 
into table-calculation-software or databases as CSV-file comma separated values

the code has some additional useful functions as there are
- PrintFileNameDateTime() printing the path and filename of sourcecode file this program was generated with

- boolean TimePeriodIsOver  a non-blocking timing-function based on millis which is suitable for 
  timed execution in a regular manner (repeat every n milliseconds)

- BlinkHeartBeatLED() blinks the onboard-LED of ESP32 nodeMCU-boards. Gives visual feedback if the code is running  

The lines of code are grouped by functionality into several functions
The functions name says what the function does

I use this code for easy datalogging on a computer with a python-code that acts as the UDP-listener for 
incoming messages. Inside your ESP32-code you have to adjust the IP-adress to the receiver 
and the portnumber must be the same on sender (ESP32) and receiver-side 

In the python-code The header is used to create a file with the header as filename and extension ".txt" or if file 
is already existant to append the actual received UDP-message at the end of the file.

here is the python-code that does this. I tested it with python 3.9.2 for windows
#Start of python-code
# very simple and short upd-receiver based on python-code I found here
# https://www.studytonight.com/network-programming-in-python/working-with-udp-sockets#

import socket

sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)      # For UDP

udp_host = socket.gethostname()            # Host IP
udp_port = 4210                     # specified port to connect

sock.bind((udp_host,udp_port))
print ("Waiting for client...")

HeaderDelimitChar = "$"

while True:
  data,addr = sock.recvfrom(1024)         #receive data from client
  print("data #",data,"#")
  Msg = data.decode('utf-8')
  print ("Received Message: #",Msg,"# from",addr)
  EndOfHeader = Msg.find(HeaderDelimitChar)
  HeaderBytes = Msg[0:EndOfHeader]
  FileName = HeaderBytes + ".txt"
  print("Filename #",FileName,"#")
  myFile = open(FileName, "a+")
  EndOfStr = data.find(0)
  MsgToWrite = Msg[EndOfHeader + 1 :1024] + '\r'
  myFile.write(MsgToWrite);
  myFile.close()
  print ("Data #",MsgToWrite,"#")

#End of python-code

For learning more about python just google with keyword "python" "your keyword of interest"  
 */

vgs

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