hi @ all
I started to get in touch with mqtt. Using shellies via mqtt is no problem. But now I want to send measurement date from another raspberry PI to the build in broker.
I installed paho-mqtt on the client raspberry. The following small code is also provided with paho-mqtt.
#include “stdio.h”
#include “stdlib.h”
#include “string.h”
#include “MQTTClient.h”
#define ADDRESS “xxx.xxx.x.xxx:1883”
#define CLIENTID “ExampleClientPub”
#define TOPIC “MQTTExamples”
#define PAYLOAD “Hello World!”
#define QOS 1
#define TIMEOUT 10000L
int main(int argc, char* argv[])
{
MQTTClient client;
MQTTClient_connectOptions conn_opts = MQTTClient_connectOptions_initializer;
MQTTClient_message pubmsg = MQTTClient_message_initializer;
MQTTClient_deliveryToken token;
int rc;
MQTTClient_create(&client, ADDRESS, CLIENTID,
MQTTCLIENT_PERSISTENCE_NONE, NULL);
conn_opts.keepAliveInterval = 20;
conn_opts.cleansession = 1;
if ((rc = MQTTClient_connect(client, &conn_opts)) != MQTTCLIENT_SUCCESS)
{
printf("Failed to connect, return code %d\n", rc);
exit(-1);
}
pubmsg.payload = PAYLOAD;
pubmsg.payloadlen = strlen(PAYLOAD);
pubmsg.qos = QOS;
pubmsg.retained = 0;
MQTTClient_publishMessage(client, TOPIC, &pubmsg, &token);
printf("Waiting for up to %d seconds for publication of %s\n"
"on topic %s for client with ClientID: %s\n",
(int)(TIMEOUT/1000), PAYLOAD, TOPIC, CLIENTID);
rc = MQTTClient_waitForCompletion(client, token, TIMEOUT);
printf("Message with delivery token %d delivered\n", token);
MQTTClient_disconnect(client, 10000);
MQTTClient_destroy(&client);
return rc;
}
compiling is succsessfull and I got the following output:
Waiting for up to 10 seconds for publication of Hello World!
on topic MQTTExamples for client with ClientID: ExampleClientPub
Message with delivery token 1 delivered
so think the host adress is ok. I then added a generic mqtt thing with “ExampleClientPub” bas ID. After that I added a channel -> text value an channel ID “MQTTExamples”
The thing is online. but after executing the test program again no text is displayed when monitoring the thing in the control section of the paper UI.
I would be very grateful for some help from experts.
By the way I’m using openhab 2.5.
regards