ESP8266 Community Forum

i'm trying to publish some variable to MQTTBox from a very simple push button counter experiment... the experiment also lights up an rgbled with random colors, I'm successful at publishing the button count and the random color values to the serial printer, but i'm having trouble doing the same using similiar 'client.publish' commands... i'm not sure what the parameter should be for a variables, the count and the rgb values.....

this is a long overdue follow up to my previous:
RGBLED.H LIBRARY ON ESP8266 VS. UNO
viewtopic.php?f=160&t=16042

here's the sketch, a little messy and unstable but hey, it works....

It is just a shot in the dark after quick look without lengthy diagnosis and not familiar with MQTT

try for line #136

instead of

no joy... although, i think you are on to something... I'll keep noodling on it, and post the original sketch in a follow up sketch, i copy and pasted from, i don't think it's an MQTTBox problem because i get the error , at the verify step in arduino ide... before i can even upload, and the messages i send to MQTTBox are correct, just the variable line of code that seems to be the problem, hence i commented it out to get the experiment to work...

Arduino: 1.8.2 (Windows 7), Board: "NodeMCU 1.0 (ESP-12E Module), 80 MHz, 115200, 4M (3M SPIFFS)"

C:\Users\GADAWE\Documents\Arduino\node_ct_rgb_box\node_ct_rgb_box.ino: In function 'void loop()':

node_ct_rgb_box:136: error: no matching function for call to 'PubSubClient::publish(const char [12], String)'

client.publish("OsoyooDataF",String(buttonPushCounter));

^

C:\Users\GADAWE\Documents\Arduino\node_ct_rgb_box\node_ct_rgb_box.ino:136:61: note: candidates are:

In file included from C:\Users\GADAWE\Documents\Arduino\node_ct_rgb_box\node_ct_rgb_box.ino:2:0:

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:130:12: note: boolean PubSubClient::publish(const char*, const char*)

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

^

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:130:12: note: no known conversion for argument 2 from 'String' to 'const char*'

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:131:12: note: boolean PubSubClient::publish(const char*, const char*, boolean)

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

^

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:131:12: note: candidate expects 3 arguments, 2 provided

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:132:12: note: boolean PubSubClient::publish(const char*, const uint8_t*, unsigned int)

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

^

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:132:12: note: candidate expects 3 arguments, 2 provided

C:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:133:12: 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:\Program Files\arduino-1.8.2\libraries\pubsubclient\src/PubSubClient.h:133:12: note: candidate expects 4 arguments, 2 provided

exit status 1
no matching function for call to 'PubSubClient::publish(const char [12], String)'

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

here's the original sketch i downloaded from osoyoo [where i purchased my starter kit] and mortified for my experiment.....

/* ___ ___ ___ _ _ ___ ___ ____ ___ ____
* / _ \ /___)/ _ \| | | |/ _ \ / _ \ / ___) _ \| \
*| |_| |___ | |_| | |_| | |_| | |_| ( (__| |_| | | | |
* \___/(___/ \___/ \__ |\___/ \___(_)____)___/|_|_|_|
* (____/
* Use the NodeMCU send switch button status to MQTT client via WiFi
* Tutorial URL:
* CopyRight www.osoyoo.com
*/
#include <ESP8266WiFi.h>
#include <PubSubClient.h>

int BUTTON_PIN = D2; //button is connected to GPIO pin D1
// Update these with values suitable for your network.
const char* ssid = "********";//put your wifi ssid here
const char* password = "********";//put your wifi password here.
const char* mqtt_server = "broker.mqttdashboard.com";
//const char* mqtt_server = "iot.eclipse.org";

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];

void setup_wifi() {
delay(100);
// We start by connecting to a WiFi network
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
randomSeed(micros());
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length)
{

} //end callback

void reconnect() {
// Loop until we're reconnected
while (!client.connected())
{
Serial.print("Attempting MQTT connection...");
// Create a random client ID
String clientId = "ESP8266Client-";
clientId += String(random(0xffff), HEX);
// Attempt to connect
//if you MQTT broker has clientID,username and password
//please change following line to if (client.connect(clientId,userName,passWord))
if (client.connect(clientId.c_str()))
{
Serial.println("connected");
//once connected to MQTT broker, subscribe command if any
client.subscribe("OsoyooCommand");
} else {
Serial.print("failed, rc=");
Serial.print(client.state());
Serial.println(" try again in 5 seconds");
// Wait 5 seconds before retrying
delay(5000);
}
}
} //end reconnect()

void setup() {
Serial.begin(115200);
setup_wifi();
client.setServer(mqtt_server, 1883);
client.setCallback(callback);
pinMode(BUTTON_PIN,INPUT);
}

void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
long now = millis();
int status;
//send message every 2 second
if (now - lastMsg > 2000) {
lastMsg = now;
status=digitalRead(BUTTON_PIN);
String msg="Button status: ";
if(status==HIGH )
{
msg= msg+ "Pressed";
char message[58];
msg.toCharArray(message,58);
Serial.println(message);
//publish sensor data to MQTT broker
client.publish("OsoyooData", message);
}
else
{
msg= msg+ " Not Press";
char message[58];
msg.toCharArray(message,58);
Serial.println(message);
//publish sensor data to MQTT broker
client.publish("OsoyooData", message);
}
}

}