UART --> MQTT

[beho1der]

Is it possible to add new functionality(UART --> MQTT): from the terminal, the publicat of the data in the mqtt topic. It is necessary for interaction with other devices
Example:
send data to serial --> #mqttmydevice test-string
mqtt <--- mqtt_root_topic/mydevice/test-string

[xoseperez]

I like this one. It would be a great addition to use with RFID or barcode readers...

[AlbertWeterings]

Hi,

I created something like this data going from UART to MQTT. As I only needed a quick and dirty working approach I high jacked the RF-Bridge code for it. I will attache the file so you have an idea.

kwhalbert.zip

[AlbertWeterings]

I tried to make a Pull request sorry that went wrong.
I was working on this enhancement it works partially and need some help. With these code changes you will be able to receive data via UART and it will be send to MQTT. The opposite way I can't get to work as somehow I can't get to the data received via MQTT maybe someone knows a solution.

In espurna add on line 150
#ifdef UARTtoMQTT
UARTtoMQTTSetup();
#endif

in Arduino.h add on line 63
#define UARTtoMQTT

in general.h add on line 557
#define MQTT_TOPIC_UARTIN "uartin"
#define MQTT_TOPIC_UARTOUT "uartout"

in hardware.h add on line 1425
#elif defined(UARTtoMQTT)

// Info
#define MANUFACTURER        "Albert"
#define DEVICE              "UART_experiment"
#define SERIAL_BAUDRATE     115200

// Remove UART noise on serial line
#define TERMINAL_SUPPORT        0
#define DEBUG_SERIAL_SUPPORT    0

// Buttons
#define BUTTON1_PIN         0
#define BUTTON1_MODE        BUTTON_PUSHBUTTON | BUTTON_DEFAULT_HIGH

// LEDs
#define LED1_PIN            1
#define LED1_PIN_INVERSE    1

Add a file uart_mqtt.ino with the following content
#ifdef UARTtoMQTT

#include
#include <Ticker.h>

// -----------------------------------------------------------------------------
// GLOBALS TO THE MODULE
// -----------------------------------------------------------------------------
const byte numChars = 100;
char receivedChars[numChars]; // an array to store the received data
boolean newData = false;

void _recvWithEndMarker() {
static byte ndx = 0;
char endMarker = '\n';
char rc;

while (Serial.available() > 0 && newData == false) {
rc = Serial.read();

if (rc != endMarker) {
  receivedChars[ndx] = rc;
  ndx++;
  if (ndx >= numChars) {
    ndx = numChars - 1;
  }
}
else {
  receivedChars[ndx] = '\0'; // terminate the string
  ndx = 0;
  newData = true;
}

}
}

void _sendNewData() {
if (newData == true && MQTT_SUPPORT) {
#if MQTT_SUPPORT
mqttSend(MQTT_TOPIC_UARTIN, receivedChars); // publish: UART -> mqtt bus
#endif
newData = false;
}
}

#if MQTT_SUPPORT
void _UARTtoMQTTMqttCallback(unsigned int type, const char * topic, const char * payload) {
if (type == MQTT_CONNECT_EVENT) {
mqttSubscribe(MQTT_TOPIC_UARTOUT);
DEBUG_MSG_P(PSTR("[UARTtoMQTT] MQTT Subscribe topic:\n"), MQTT_TOPIC_UARTOUT);
}

if (type == MQTT_MESSAGE_EVENT) {

    // Match topic
    String t = mqttTopicKey((char *) topic);
    //DEBUG_MSG_P(PSTR("[UARTtoMQTT] t= :\n"), t);

    bool isUARTOut = t.equals(MQTT_TOPIC_UARTOUT);

    if (isUARTOut) {
      //send the received MQTT message to Serial

    }

}

}
#endif

// -----------------------------------------------------------------------------
// SETUP & LOOP
// -----------------------------------------------------------------------------

void UARTtoMQTTSetup() {

#if MQTT_SUPPORT
    mqttRegister(_UARTtoMQTTMqttCallback);
#endif

// Register oop
espurnaRegisterLoop(UARTtoMQTTLoop);

}

void UARTtoMQTTLoop() {
_recvWithEndMarker();
_sendNewData();
}

#endif

It is not the most nice code but it works for one direction. In uart_mqtt.ino you will find a line //send the received MQTT message to Serial from here I got stuck hope someone can help a bit.

[beho1der]

Thanks, It would be nice to include in the main branch of the project

[AlbertWeterings]

for now my experiment can be found here:
https://github.com/xoseperez/espurna/compare/master...AlbertWeterings:UARTtoMQTT?expand=1
It still needs work as it only works from UART to MQTT not opposite My programming skills are basic and until now I could not find a way to pass the via MQTT received data to UART.

[AlbertWeterings]

My code works both way's now I'm having it sending a RSS feed over MQTT and UART to a ticker as test and it is running fine.

@xoseperez can you have a look at what I created and add it? it is now added as a hardware board more nice will be if it could be added as feature to all hardware that don't have anything connected to the UART. I think you will have a perfect overview of that.

[xoseperez]

@AlbertWeterings I have just merged your code. Thank you! I have made some small changes to follow the code style convention and moved some things up and down. It's in the dev branch now.

[xoseperez]

Staged for release

[rollercontainer]

Could this be used for a IR transmitter for smart meters?