💬 Building a MQTT Gateway

  • Admin

    This thread contains comments for the article "Building a MQTT Gateway" posted on MySensors.org.

  • Quick question.
    I have built GatewayW5100MQTTClient according to mysensors.
    It works and relays my nodes.
    However, my old gateway with MqTT delivered the messages with my selected prefix and then node/child number + variable/sensor.
    Ex MyMQTT/1/1/S_TEMP
    Now the new gateway with MqTT delivers node and child and more like this:
    MyMQTT/1/1/x/x/x where X is some number.
    It does not display S_TEMP.
    And what are the extra "numbers"?

    And it also displays when the node starts up some MqTT messages that are empty ex:
    MyMQTT/1/255/3/0/1 with no information.
    I do not know what publishes these..

    For relevance, the sketches I upload are the ones in the new mysensors library, ex Atmospheric Pressure Sensor.

  • Hardware Contributor

    The new MQTT gateway exposes the serial api to MQTT. It has less functionality.

    The old client gateway was a controller and translated the protocol to more readable messages and had a node-id handling.

    I had the same problem and switched to node-red with a serial gateway.

  • Admin

  • @FotoFieber

    How do you mean it is a problem? Everything works, just needed to know what the extra was 🙂
    I too use NODE RED, but just listening on MQTT and then putting the info into mysql databases.

    Thank you! I have used search, but it is difficult when you do not know what you are searching for 🙂 And all information about 2.0 is overwhelming at the time being for me.

  • Admin

    Thanks, good feedback @Nicklas-Starkel .

    I just updated the main MQTT page, moving some of the instructions from the forum.

  • Seems that the W5100 sketch of the MQTT gateway is missing #include <SPI.h>.
    I had to add it before #include <Ethernet.h>.

  • As Ernst79 already mentioned: please add #include <SPI.h> as a switch to your code, thank you!

  • Admin

  • Is it possible to have the MQTT client also act as a network gateway?

  • Admin

    Nope, sorry. You have to have to introduce a broker or controller acting as MQTT server.

  • The old network gateway with mqtt seems to be removed and the client version is the one that id preferred. Is it possible to have both mqtt server and network gateway in that version?

  • Sorry for my ignorance but I would like to know how to connect the gateway to the sensor.
    As I understand it, the radio communication is responsible for it, so can I put arduino + NRF24L01 + sensor at the other end?
    Thank you!

  • @DIM said:

    my ignorance but I would like to k

    The gateway is a arduino with NRF24L01+ (or RFM69) and serial/network/RS485 component. The sensor is another arduino with NRF24L01+ (or RFM69) and the sensor that are attached. The gateway is then acting as a translator from the NRF24L01+ (or RFM69) radiosignal to the medium that can talk to your controller

  • I thought that the gateway could be done only with the ESP8266 module.

  • If you're using an ESP8266 and you find it "SOFT WDT resetting" whenever a node tries to send a message, try moving the wire from GPIO4 to GPIO5 - There are a few esp12E boards which have been incorrectly screen printed - worked for me with this board!

  • Regarding ACK flag in MQTT.
    If a sensor sends data to the gateway, and it requests an ACK.
    It is the gateway that responds with an ACK, not the controller.

    How do one utilize the ACK flag in MQTT?
    Or rather, how do one get the ACK to display in a MQTT message?

    void receive(const MyMessage &message) {
    int value = debouncer.read();
    //We only expect one type of message from controller. But we better check anyway.
     if (message.isAck()) {
        Serial.println("This is an ack from gateway");

    Should I write a codesnippet like the above but one that sends a message back to the gateway, that the ACK was received?
    And also, if an ACK was not received that the sensor should try to send the message again.

  • I have set up an MQTT gateway running on a Wemos D1, and a motion sensor running on an arduino nano.

    It seems to work successfully, but I had to define MY_NODE_ID in the sensor sketch because the negotiation for this is done by the controller. Presumably, I'm going to have to program my controller to respond to the mqtt message being sent to negiotiate the id, but I cannot find any documentation on the correct reply. Does someone have a link?

    The mqtt message being sent to negotiate the node id was

    mygateway1-out/255/255/3/0/3 (null)

  • I believe the node id will always be 0 for gateways so the examples are a little misleading. For example the output shows connections with a node id of 2 (e.g. mygateway1-out/2/1/1/0/49 55.722519;13.018121;13)

  • Can this be used with RabbitMQ as broker?

  • Not sure if you want to leave the GPS on there unless that isn't your house with the double hot tub in tha back garden 🙂

  • Hi, is it possible to configure the MQTT gateway to let me in to port 5003 via telnet and read the communication message (not MQTT payloads) there also?

  • Not sure if this helps but for debugging I use MQTT spy (https://github.com/eclipse/paho.mqtt-spy/wiki) for tracking the comms

  • Mod

    There is also mqtt fx that can be used to see what's going on on the mqtt server

  • I know what is going on the MQTT server and I am subscribed to the topics the Mysensors gateway created and publish data to it.

    But, I want to know what is going on the GATEWAY as well. I'd like to see messages like these when I telnet to the gateway on port 5003 (that's the default as I remember)

    0;255;3;0;9;Starting gateway (RNNGA-, 2.0.0)
    0;255;3;0;9;TSM:GW MODE
    0;255;3;0;9;No registration required
    0;255;3;0;9;Init complete, id=0, parent=0, distance=0, registration=1
    0;255;3;0;9;TSP:MSG:READ 255-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0:
    0;255;3;0;9;TSP:MSG:FPAR REQ (sender=255)
    0;255;3;0;9;TSP:CHKUPL:OK (FLDCTRL)
    0;255;3;0;9;TSP:MSG:GWL OK
    0;255;3;0;9;TSP:MSG:SEND 0-0-255-255 s=255,c=3,t=8,pt=1,l=1,sg=0,ft=0,st=bc:0
    0;255;3;0;9;TSP:MSG:READ 255-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0:

  • Mod

    There is the tool MYSController that connects to the gateway and shows all the messages

  • Hardware Contributor

    My gateway seems to be constantly repeating the following on the serial monitor:

    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2
    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2
    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2

    Does this look like its in a reset loop or would you say there is some other issue going on?

    If needed, my config is a Arduino Mega 2560 witha w5100 shield on top. I have specified the IP address of itself, the subnet, gateway, mqtt client IP (Controller), the mqtt topics, port, changed my LED pins.

    I have a node with a button next to me, when i press it the message is picked up by the gateway. Below is what happens in the serial monitor when i press the node button.

    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2
    0;255;3;0;9;Sending message on topic: Gateway1-out/3/3/1/0/2

    I'm a little confused at what point to troubleshoot here because I seem to think that for some reason it keeps refreshing its connection to the MQTT server. Not too sure why it is pushing a message to the topic of "Gateway1-out/0/255/0/0/18" either.

  • Mod

    @Samuel235 see if the solution suggested by tekka in https://forum.mysensors.org/post/47225 can help (downgrade board definitions to 1.6.11)

  • Mod

    @Samuel235 0_1487281026734_boardmanager.png
    In case anyone needs to know where to downgrade: Tools -> Boards ->Boards Manager -> Select version for Arduini AVR Boards.

  • Hardware Contributor

    @mfalkvidd - It is still seeming to repeatedly reconnect to the MQTT server. I've issued a ping command to the arduino from the mqtt server and its constantly pinging without an issue, even while the serial monitor shows that its reconnecting. I'de be interested to know if anyone else is running the MQTT client gateway with MySensors V2.1. I used to run it when it was first introduced into the development environment in 1.6 and its been fine for over a year, but i upgraded to V2.1 and now i get this. So, i don't actually know if it is supposed to keep reconnecting to the MQTT server. I have read somewhere here that it sends a wake/refresh packet/message to the mqtt server just to keep it alive, but they said that was every 15 seconds by default. This is happening every 5/6 seconds.

    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2
    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2
    0;255;3;0;9;Attempting MQTT connection...
    0;255;3;0;9;MQTT connected
    0;255;3;0;9;Sending message on topic: Gateway1-out/0/255/0/0/18
    0;255;3;0;9;Message arrived on topic: Gateway1-in/4/1/1/0/2

  • Mod

    i think you need to post your code just to make more complete info.

  • Hardware Contributor

    I would like to know if anyone else's MQTT Gateway does this?

    If this is the normal procedure I can carry on with config work for the nodes. Its pretty weird, the serial monitor is showing this but the gateway seems to be functioning. Nodes are talking to it. I'm not sure on that output topic though, why would it be sending something to Gateway1-out/0/255/0/0/18?

  • Hardware Contributor

    @gohan - I have not touched the MySensors.h or MyConfig.h but the sketch is below:

     * The MySensors Arduino library handles the wireless radio link and protocol
     * between your home built sensors/actuators and HA controller of choice.
     * The sensors forms a self healing radio network with optional repeaters. Each
     * repeater and gateway builds a routing tables in EEPROM which keeps track of the
     * network topology allowing messages to be routed to nodes.
     * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
     * Copyright (C) 2013-2015 Sensnology AB
     * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
     * Documentation: http://www.mysensors.org
     * Support Forum: http://forum.mysensors.org
     * This program is free software; you can redistribute it and/or
     * modify it under the terms of the GNU General Public License
     * version 2 as published by the Free Software Foundation.
     * Version 1.0 - Henrik Ekblad
     * The W5100 MQTT gateway sends radio network (or locally attached sensors) data to your MQTT broker.
     * The node also listens to MY_MQTT_TOPIC_PREFIX and sends out those messages to the radio network
     * LED purposes:
     * - To use the feature, uncomment WITH_LEDS_BLINKING in MyConfig.h
     * - RX (green) - blink fast on radio message recieved. In inclusion mode will blink fast only on presentation recieved
     * - TX (yellow) - blink fast on radio message transmitted. In inclusion mode will blink slowly
     * - ERR (red) - fast blink on error during transmission error or recieve crc error
     * See http://www.mysensors.org/build/esp8266_gateway for wiring instructions.
     * nRF24L01+  ESP8266
     * VCC        VCC
     * CE         GPIO4
     * CSN/CS     GPIO15
     * SCK        GPIO14
     * MISO       GPIO12
     * MOSI       GPIO13
     * Not all ESP8266 modules have all pins available on their external interface.
     * This code has been tested on an ESP-12 module.
     * The ESP8266 requires a certain pin configuration to download code, and another one to run code:
     * - Connect REST (reset) via 10K pullup resistor to VCC, and via switch to GND ('reset switch')
     * - Connect GPIO15 via 10K pulldown resistor to GND
     * - Connect CH_PD via 10K resistor to VCC
     * - Connect GPIO2 via 10K resistor to VCC
     * - Connect GPIO0 via 10K resistor to VCC, and via switch to GND ('bootload switch')
      * Inclusion mode button:
     * - Connect GPIO5 via switch to GND ('inclusion switch')
     * Hardware SHA204 signing is currently not supported!
     * Make sure to fill in your ssid and WiFi password below for ssid & pass.
    // Enable debug prints to serial monitor
    #define MY_DEBUG
    // Enables and select radio type (if attached)
    #define MY_RADIO_NRF24
    //#define MY_RADIO_RFM69
    // Set this node's subscribe and publish topic prefix
    #define MY_MQTT_PUBLISH_TOPIC_PREFIX "Gateway1-out"
    #define MY_MQTT_SUBSCRIBE_TOPIC_PREFIX "Gateway1-in"
    // Set MQTT client id
    #define MY_MQTT_CLIENT_ID "mysensors-1"
    // W5100 Ethernet module SPI enable (optional if using a shield/module that manages SPI_EN signal)
    //#define MY_W5100_SPI_EN 4
    // Enable Soft SPI for NRF radio (note different radio wiring is required)
    // The W5100 ethernet module seems to have a hard time co-operate with
    // radio on the same spi bus.
    #if !defined(MY_W5100_SPI_EN) && !defined(ARDUINO_ARCH_SAMD)
    #define MY_SOFTSPI
    #define MY_SOFT_SPI_SCK_PIN 14
    #define MY_SOFT_SPI_MISO_PIN 16
    #define MY_SOFT_SPI_MOSI_PIN 15
    // When W5100 is connected we have to move CE/CSN pins for NRF radio
    #ifndef MY_RF24_CE_PIN
    #define MY_RF24_CE_PIN 5
    #ifndef MY_RF24_CS_PIN
    #define MY_RF24_CS_PIN 6
    // Enable these if your MQTT broker requires usenrame/password
    //#define MY_MQTT_USER "username"
    //#define MY_MQTT_PASSWORD "password"
    // Enable MY_IP_ADDRESS here if you want a static ip address (no DHCP)
    #define MY_IP_ADDRESS 192,168,0,22
    // If using static ip you need to define Gateway and Subnet address as well
    #define MY_IP_GATEWAY_ADDRESS 192,168,0,1
    #define MY_IP_SUBNET_ADDRESS 255,255,255,0
    // MQTT broker ip address or url. Define one or the other.
    //#define MY_CONTROLLER_URL_ADDRESS "m20.cloudmqtt.com"
    #define MY_CONTROLLER_IP_ADDRESS 192, 168, 0, 21
    // The MQTT broker port to to open
    #define MY_PORT 1883
    // Enable inclusion mode
    // Enable Inclusion mode button on gateway
    // Set inclusion mode duration (in seconds)
    // Digital pin used for inclusion mode button
    // Set blinking period
    // Flash leds on rx/tx/err
    // Uncomment to override default HW configurations
    #define MY_DEFAULT_ERR_LED_PIN 11  // Error led pin
    #define MY_DEFAULT_RX_LED_PIN  12  // Receive led pin
    #define MY_DEFAULT_TX_LED_PIN  13  // the PCB, on board LED
    #include <Ethernet.h>
    #include <MySensors.h>
    void setup()
    void presentation()
    	// Present locally attached sensors here
    void loop()
    	// Send locally attached sensors data here

    EDIT: My issue was resting on the MQTT Server, had OpenHAB and MySensors gateway using same ClientID.

  • @Gabor-Bognar I also need to be able to do this.
    Is there a solution to have a port 1883 for MQTT and port 5003 for telnet?

  • Hi,

    There is a missing parameter in your sketch :
    // The MAC address can be anything you want but should be unique on your network.
    // Newer boards have a MAC address printed on the underside of the PCB, which you can (optionally) use.
    // Note that most of the Ardunio examples use "DEAD BEEF FEED" for the MAC address.
    #define MY_MAC_ADDRESS 0x90, 0xA2, 0xDA, 0x10, 0xEB, 0x1D

    In normal way, this line is note really important.
    But if you want to use two separate MQTT on the same network, you should add this line and modify the mac adress on the two MQTT...


  • Is it possible to have a single device acting as a ethernet gateway and an mqtt gateway?

  • Mod

    No, but if you really really need the 2 connections you could use node-red to read data from the ethernet gateway and mirror them to mqtt

  • I am wondering why you cannot built the ethernet gateway and combine the mqtt client sketch into it? I am trying to shift towards mqtt (experiment) while still having sensors available in Vera. I have the MQTT plugin on vera but have not yet figured out how to use the child device to control devices via MQTT. It seems like a waste to control the MQTT device only through Vera and I would never be able to shift away from vera that way. I'm new to this so I am still trying to understand the entire picture.


  • Mod

    @scottdube my guess is that nobody with sufficient knowledge has had enough motivation and time to see if it can be done - especially since other solutions (nodered, myscontroller) already exist.

  • @mfalkvidd I am missing something, the reason I want it to do both is that I want the flexibility to use Node Red and my Vera controller. I was thinking that as I built new sensors they would run through node red but be available to vera as well. I'm sure I just don't yet understand how people are designing their hybrid systems yet. My solution was to have the mysensors gateway also put the sensors values out to the mqtt broker and vice versa but there must be another way I am not seeing yet...


  • Mod

    maybe it is time to switch away from Vera to something else that still uses zwave?

  • @gohan Maybe that is the answer, I'll research that a bit... That was what I was hoping to do over time with my strategy...

  • Mod

  • I'd like to have a very simple (intra-home) web page in my raspberry PI that would be updated with all of my nodes information and that could also turn on/off nodes with actuators (basically I don't want to have a fancy controller).
    If I understood correctly, with this MQTT Ethernet Gateway I could implement this by running Mosquito that would subscribe information from each node, through this MQTT gateway.
    Does this mean I can avoid having a controller?

  • Mod

    Technically speaking yes but I don't see the point in reinventing the wheel

  • I rebuilt my serial gateway to a MQTT gateway. FWIW I had to connect 5V to my WizNET (W5100) Ethernet module (3.3V did not work) I couldn't make DHCP work so I used a fixed IP. Finally I had to replace the capacitor over the radio power feed from 4.7 uF capacitor to a 100 uF capacitor (That made a big difference!). Works great now.

  • It should have:

    void presentation() {
    sendSketchInfo("Gateway node", "1.0");

    In order to show the right topology in some tools, i.e. mycontroller.org


  • Hi, is there any case for this gateway ? I wouldn't want all those wires to lay around in plain view..

  • Mod

    @sionut "this gateway" is a bit ambiguous. The mqtt gateway can be based on different Arduinos and use different expansion boards, which will make a big difference for casing. Which variant are you planning to build?

  • That's a good question. 🙂 I didn't realize that the arduino board is not specified (neither in this tutorial nor in the ethernet one).
    However, I see that the ethernet gateway project (https://www.mysensors.org/build/ethernet_gateway) mentions that any arduino board would be fine. Since I'm only a beginner, I don't know what board would suffice for this kind of project. Could you recommend me the cheapest Arduino board that can do the job ?

  • Mod

    @sionut if you have wifi, I would suggest esp8266 (wemos d1 mini if you want a specific board recommendation). It has built-in wifi so you don’t need an expansion board. Guide: https://www.mysensors.org/build/esp8266_gateway It can be run in mqtt mode if you prefer mqtt over plain tcp.

    If you prefer ethernet, the Arduino Uno seems to be the one that matches the W5100 shield.

  • Great. I have wifi, so I will use the esp8266. I think I will continue with this board here as it's something I can find in a local store nearby.

    I just need one more clarification though: in the ESP8266 gateway page I see the following paragraph:

    Just connect the radio, install gateway software and you're good to go.

    Now, considering that the board already has WIFI, why do I need the radio ?

  • Mod

    @sionut the "normal" use of a MySensors network is to have multiple nodes using a cheap radio (nrf24) and a low-power microcontroller (Arduino Pro Mini is much more power efficient than the esp8266).

    The gateway connects the nodes (using nrf24) to your controller. Without a radio, the gateway can't talk to the nodes. See this page in the gatting started guide for a more complete explanation.

    However, if you don't need battery-powered nodes you could get a bunch of esp8266 and configure them all as gateways without adding radios to them.

  • Is it feasible to have MySensors talking to an MQTT Broker like Mosquito (running on a rpi) via radio so using say a USB gateway AND also have WiFi modules talking to Mosquito and then having Mosquito talking to HomeAssistant? I see where this is doable via MySensors and radio links OR it can be done using WiFi modules but what if you want both?

  • Yes that is possible. Mysensors connects through the gateway to MQTT and the WiFi modules to mosquitto directly. You can use the mysensors protocol also over the WiFi modules I believe.
    I'm not sure if it is possible with an usb gateway though, but for sure with a WiFi based gateway like ESP 32.
    Once you are on mqtt you can connect to and from all devices/controllers that support it.

  • Mod

    @alaskadiy I'd make a raspberry gateway with radio directly on the raspberry, much cleaner solution

  • @gohan With a radio directly on the rPi would mosquito talk to both the radio and WiFi? I assume it would, I would think mosquito would just be a service that the radio or WiFi sends/receives data to but have not seen anyone talk about it.


  • @electrik Sounds like what I want to do can be done, thanks.

  • Mod

    @alaskadiy no. The gateway (running as a service) would talk to the radio and to mosquitto. Mosquitto is unable to talk directly to the radio.

  • Hi guys. I'm using an Arduino Uno+5100 based MQTT gateway. It works fine for it's gateway function but I'm not beeing able to send local sensor data. Is that possible?

  • Mod

    @guillermo-schimmel it should be possible to call present() and send() just like on a regular node. Could you share your sketch and the debug output?

  • @mfalkvidd thanks. I just did that on a dedicated post. It's driving me crazy.


  • Mod

    @guillermo-schimmel ok, lets discuss there then so we don't split the effort and information in separate threads.

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