pubsubclient communication

how can i publish RSSI() and SSID() values by using pubsubclient.

float n = WiFi.scanNetworks();
Serial.printf("%d network(s) found\n", n); //Scan start ... 5 network(s) found
if (n == 0) {
Serial.println("no wifi`s are connected");
}
else {
for (float i = 0; i < n; i++)
{
Serial.printf("%d: %s, Ch:%d (%ddBm)\n", i + 1, WiFi.SSID(i).c_str(), WiFi.channel(i), WiFi.RSSI(i)); //1: Tech_D005107, Ch:6 (-72dBm)

** mqttclient.publish("ssid",WiFi.SSID(i).c_str());**
** mqttclient.publish("rssi",WiFi.RSSI(i));**

//i need to rewrite the above two lines
}

i am getting error friends can you help me

What is the error?

C:\Users\extrcha\Documents\Arduino\client_tag\client_tag.ino: In function 'void ScanAndConnect()':

client_tag:104:43: error: no matching function for call to 'PubSubClient::publish(int [50], int32_t)'

mqttclient.publish(msg1,WiFi.RSSI(i));

^

C:\Users\extrcha\Documents\Arduino\client_tag\client_tag.ino:104:43: note: candidates are:

In file included from C:\Users\extrcha\Documents\Arduino\client_tag\client_tag.ino:3:0:

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:141:12: note: boolean PubSubClient::publish(const char*, const char*)

__ boolean publish(const char* topic, const char* payload);__

^

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:141:12: note: no known conversion for argument 1 from 'int [50]' to 'const char*'

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:142:12: note: boolean PubSubClient::publish(const char*, const char*, boolean)

boolean publish(const char* topic, const char* payload, boolean retained);

^

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:142:12: note: candidate expects 3 arguments, 2 provided

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:143:12: note: boolean PubSubClient::publish(const char*, const uint8_t*, unsigned int)

boolean publish(const char* topic, const uint8_t * payload, unsigned int plength);

^

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:143:12: note: candidate expects 3 arguments, 2 provided

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:144:12: note: boolean PubSubClient::publish(const char*, const uint8_t*, unsigned int, boolean)

boolean publish(const char* topic, const uint8_t * payload, unsigned int plength, boolean retained);

^

C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:144:12: note: candidate expects 4 arguments, 2 provided

exit status 1
no matching function for call to 'PubSubClient::publish(int [50], int32_t)'

Please post your full sketch.

If possible, you should always post code directly in the forum thread as text using code tags:

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#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>

const char* msg;
const char* msg1;

#define ssid "ssid"
#define password "pass"
#define mqtt_server "broker_ip"

#define client_name "NodeMCU 8CH"

const char* intopic = "home/esp";
const char* outtopic = "home/msg";

const char* outtopic1 = "home/msg1";

WiFiClient espClient;
PubSubClient mqttclient(espClient);

int status = WL_IDLE_STATUS;
//WL_IDLE_STATUS: it is a temporary status assigned when WiFi.begin()
//is called and remains active until the number of attempts expires
//(resulting in WL_CONNECT_FAILED) or a connection is established (resulting in WL_CONNECTED);

void setup(void)
{
// Start Serial
Serial.begin(115200);//bits per secound
Serial.println("Attempting to connect to WPA network...");
Serial.print("SSID: ");

// Connect to WiFi
status = WiFi.begin(ssid, password);
// WiFi.mode(WIFI_STA);
if (status != WL_CONNECTED) //WL_CONNECTED: assigned when connected to a WiFi network;
{
delay(500);
Serial.print(".");
}
else {
Serial.println("Connected to wifi");
Serial.println("\nStarting connection...");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}
mqttclient.setServer(mqtt_server, 1883);
mqttclient.setCallback(callback);
}

// handle message arrived
void callback(char* topic, byte* payload, unsigned int length) {
if (strcmp(topic, intopic) == 0) {
Serial.print("Message arrived [");
Serial.print(intopic);
Serial.print("] ");
for (int i = 0; i < length; i++) {
Serial.print((char)payload*);*

  • }*
  • }*
    }
    void loop() {
  • // put your main code here, to run repeatedly:*
  • if (!mqttclient.connected()) {*
  • reconnect();*
  • }*
  • mqttclient.loop();*
  • delay(100);*
  • float n = WiFi.scanNetworks();*
  • Serial.printf("%d network(s) found\n", n); //Scan start ... 5 network(s) found*
  • if (n == 0) {*
  • Serial.println("no wifi`s are connected");*
  • }*
  • else {*
  • int a[20];*
  • float array1[20];*
  • int j = 0;*
  • for (float i = 0; i < n; i++)*
  • {*
  • Serial.printf("%d: %d, Ch:%d (%ddBm)\n", i + 1, WiFi.SSID(i).c_str(), WiFi.channel(i), WiFi.RSSI(i)); //1: Tech_D005107, Ch:6 (-72dBm)*
  • }*
  • for (int i = 0; i < n; i++) {*
  • a[j] = WiFi.RSSI(i);*
  • j++;*
  • }*
  • for (j = 0; j < n; j++) {*
  • int d = j;*
  • while ( d > 0 && array1[d - 1] < array1[d]) {*
  • //swapping*
  • int t = array1[d];*
  • array1[d] = array1[d - 1];*
  • array1[d - 1] = t;*
  • d--;*
  • }*
  • }*
  • //top 3*
  • Serial.println("Sorted order:\n");*
  • for (j = 0; j < 2; j++) {*
  • Serial.println(array1[j]);//top three rssi values*
  • }*
  • //we need to send rssi,ssid,tagid at a time...!*
  • for (float i = 0; i < n; i++)*
  • {*
  • Serial.printf("%d: %d, Ch:%d (%ddBm)\n", i + 1, WiFi.SSID(i).c_str(), WiFi.channel(i), WiFi.RSSI(i)); //1: Tech_D005107, Ch:6 (-72dBm)*
  • Serial.printf("sending messages:");*
  • msg = WiFi.SSID(i).c_str();*
  • Serial.printf("sending message");*
  • Serial.println(msg);*
  • mqttclient.publish(outtopic, msg);*
    ** msg1 = WiFi.RSSI(i);**
    ** char msg2 = msg1;**
    ** Serial.printf("sending message");**
    ** Serial.println(msg1);**
    ** mqttclient.publish(outtopic1, msg2);**
  • }*
  • }*
    }
    void reconnect() {
  • // Loop until we're reconnected*
  • while (!mqttclient.connected()) {*
  • Serial.print("Attempting MQTT connection...");*
  • // Attempt to connect*
  • if (mqttclient.connect(client_name)) {*
  • Serial.println("connected");*
  • // Once connected, publish an announcement...*
  • //mqttclient.publish(msgTopic, "MQTT is connected");*
  • // ... and resubscribe*
  • mqttclient.subscribe(intopic);*
  • }*
  • else {*
  • Serial.print("failed, rc=");*
  • Serial.print(mqttclient.state());*
  • Serial.println(" try again in 5 seconds");*
  • // Wait 5 seconds before retrying*
  • delay(5000);*
  • }*
  • }*
    }
    errors:
    C:\Users\extrcha\Desktop\project_demo\tag4\tag4.ino: In function 'void loop()':
    tag4:121:25: error: invalid conversion from 'int32_t {aka int}' to 'const char*' [-fpermissive]
  • msg1 = WiFi.RSSI(i);*
  • ^*
    tag4:122:19: error: invalid conversion from 'const char*' to 'char' [-fpermissive]
  • char msg2 = msg1;*
  • ^*
    tag4:125:41: error: invalid conversion from 'char' to 'const char*' [-fpermissive]
  • mqttclient.publish(outtopic1, msg2);*
  • ^*
    In file included from C:\Users\extrcha\Desktop\project_demo\tag4\tag4.ino:3:0:
    C:\Users\extrcha\Documents\Arduino\libraries\PubSubClient\src/PubSubClient.h:141:12: error: initializing argument 2 of 'boolean PubSubClient::publish(const char*, const char*)' [-fpermissive]
    _ boolean publish(const char* topic, const char* payload);_
  • ^*
    exit status 1
    invalid conversion from 'int32_t {aka int}' to 'const char*' [-fpermissive]
    the above errors

rajesh1129:
C:\Users\extrcha\Desktop\project_demo\tag4\tag4.ino: In function 'void loop()':

tag4:121:25: error: invalid conversion from 'int32_t {aka int}' to 'const char*' [-fpermissive]

msg1 = WiFi.RSSI(i);

The error is fairly self explanatory. WiFi.RSSI(i) returns an int, but for some reason you are trying to put it in a char*. You need to convert the int to a string before you can do that. For that purpose, you might find itoa() useful:
http://www.cplusplus.com/reference/cstdlib/itoa/

You also might like to study the reference page for the RSSI() function (the ESP8266WiFi library follows the API of the official Arduino WiFi library):

rajesh1129:
tag4:122:19: error: invalid conversion from 'const char*' to 'char' [-fpermissive]

char msg2 = msg1;

Now this code is just mystifying. I don't know why you would do something like that. Best thing to do is to remove it, since it serves no purpose.

Thank you pert

You're welcome. I'm glad if I was able to be of assistance. Enjoy!
Per