💬 Relay

  • wow! fantastic! ... the github link readme warns that it's not yet fully ready but the interface is already impressive!
    I still have the same question i had for nodemanager though : for measuring another battery than the one that feeds Vcc obviously another pin is needed, however why not propose as well the option of measuring such pin voltage but with Vcc as the reference rather than the internal 1.1V which most of the time makes necessary a voltage divider ? Actually i did the modification in nodemanager.cpp to use DEFAULT (~3.3V) rather than INTERNAL (1.1V) reference for a 3.3 pro mini and i can get the expected battery level without any voltage divider.

    Another unrelated question i have is : could there be any way to adapt the idea of the readVcc method (which is to measure the internal 1.1V against the Vcc reference to get Vcc) but using any voltage applied to a pin as the reference to again measure the internal 1.1 against it ? This would allow the masurement of any voltage greater than 1.1 without voltage divider while the usual method would be applied for measuring any voltage lower than 1.1 ... what did i miss that makes this impossible ?

  • Mod

    We need to use the internal reference since it is the only stable voltage source and you need the voltage divider to lower the measured voltage between 0 and 1.1v. There are not many options to choose from

  • i also just realized that there is a special AREF pin intended for what i was thinking about ... but it's not available on the mini pro.

    My measurements using Vcc as Ref have been indeed very fluctuating, however what i get was highly sufficient to monitor the battery feeding a 3.3v step up regulator to the arduino and help anticipate failure

  • I just noticed another thing that should be changed in the 'relay with button' sketch....

    S_LIGHT should be S_BINARY
    V_LIGHT shoud be V_STATUS

  • I would like to clarify operation of the sketch, where more than 1 sensors input are used along with more than 1 relay actuator. in one node

    1. Does node need unique child ID for each sensor input AND relay output?
    2. If that is the case how child ID is assigned to relay actuators in the above examples?

  • This is a nice sketch and it is very universal for relays. Now m looking for a similar sketch for digital inputs such as buttons i.e.. I would like to join both. The problem: I want to use a mega for reading status of a lot of digital outputs (min.20) of another ISP. It is only High or Low. Only when the level changes, I want the mega send a message to the gateway. I tried this "for" loop, but it didnt help. There are too many informations sent to the gateway. I imagine a solution, where only a change at the pin will create an information, that is sent to the gateway.
    Here my test, which didnt run:
    void loop()

    for (int sensor=16, pin=BIN_1; sensor<=NUMBER_OF_BIN; sensor++, pin++)
    int BUTT;
    int BUTTOLD;
    BUTT =digitalRead(pin);
    if (BUTT != BUTTOLD && BUTT !=0){
    MyMessage msg(sensor, V_TRIPPED);
    send(msg.set(BUTT ? "1" : "0"));
    wait (900);
    Has anybody an idea or a hint for me?

  • Mod

    I believe there is a logic error in the sketch as you would need to declare global variables BUTTOLD_XX unique for each button, otherwise how can you keep track of the variable between each loop and FOR iteraction?

  • Thank You for Your quick answer.
    Do I understand You correctly: I must index the BUTTOLD?
    As BUTTOLD[pin) for example or how? Where?

  • Mod

    You need to create the single variables one by one, unless somebody else has a better way to do it

  • why i can't compile for arduino pro mini on other boards i can upload

  • Mod

    @mitja-blazinsek the error messages are usually essential to figuring out. Did you get any?

  • Arduino: 1.8.1 (Windows 7), Board: "Arduino Pro or Pro Mini, ATmega168 (5V, 16 MHz)"

    In file included from c:\users\mitja\appdata\local\arduino15\packages\arduino\tools\avr-gcc\4.9.2-atmel3.5.4-arduino2\avr\include\avr\io.h:99:0,

                 from c:\users\mitja\appdata\local\arduino15\packages\arduino\tools\avr-gcc\4.9.2-atmel3.5.4-arduino2\avr\include\avr\pgmspace.h:90,
                 from C:\Users\mitja\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.6.20\cores\arduino/Arduino.h:28,
                 from sketch\button_relay.ino.cpp:1:

    C:\Users\mitja\Documents\Arduino\libraries\MySensors/hal/architecture/AVR/MyHwAVR.cpp: In function 'bool hwUniqueID(uint8_t (*)[16])':

    C:\Users\mitja\Documents\Arduino\libraries\MySensors/hal/architecture/AVR/MyHwAVR.cpp:246:26: error: 'SIGRD' was not declared in this scope

    ((uint8_t)uniqueID) = boot_signature_byte_get(0x00);


    C:\Users\mitja\Documents\Arduino\libraries\MySensors/hal/architecture/AVR/MyHwAVR.cpp:247:30: error: 'SIGRD' was not declared in this scope

    ((uint8_t)uniqueID + 1) = boot_signature_byte_get(0x02);


    C:\Users\mitja\Documents\Arduino\libraries\MySensors/hal/architecture/AVR/MyHwAVR.cpp:248:30: error: 'SIGRD' was not declared in this scope

    ((uint8_t)uniqueID + 2) = boot_signature_byte_get(0x04);


    C:\Users\mitja\Documents\Arduino\libraries\MySensors/hal/architecture/AVR/MyHwAVR.cpp:249:30: error: 'SIGRD' was not declared in this scope

    ((uint8_t)uniqueID + 3) = boot_signature_byte_get(0x01); //OSCCAL


    Multiple libraries were found for "Bounce2.h"
    Used: C:\Users\mitja\Documents\Arduino\libraries\Bounce2
    Not used: C:\Users\mitja\Documents\Arduino\libraries\Bounce2-master
    exit status 1
    Error compiling for board Arduino Pro or Pro Mini.

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

  • OK it's probaly because ia have mini with 168 chip i have to buys 328 😞 again wait 1month to arive from china

  • hello.
    I am building a node with several kind of sensors and two relays.
    My sensors use CHILD ID from 0 to 3. I would like to start child ID of relay from 4.
    How I can't do that with this sketch?
    I guess I have to change this part of sketch :
    "for (int sensor=1, pin=RELAY_PIN; sensor<=NUMBER_OF_RELAYS; sensor++, pin++) {
    // Register all sensors to gw (they will be created as child devices)
    present(sensor, S_BINARY);"



  • @lekeb
    You may do something like this:
    In Header:

    uint8_t DS_First_Child_ID = 7; //First Child-ID to be used by Dallas Bus

    an then in presentation():

    for (int i = 0; i < numSensors && i < MAX_ATTACHED_DS18B20; i++) {
        present(i + DS_First_Child_ID, S_TEMP);

    But afaik, it's not recommended to shift the ChildID's for relays but always start with 1. Imo it's better to change the ChildID's of the other attached sensors. You may also take care (in case of shifting ID's) about a consistent mapping from ID to the PINs where the relays are attached.

  • Mod

    Agreed, set you sensors to higher ID numbers like 20 or 30 and you are good to go .

  • ok thanks a lot I will try this night

  • perfect it works great. I started my temperature sensor at CHILD ID 4 and let relays from 1 to 2. I had to add also "DS_First_Child_ID" in the sent message to gateway.

  • Hi
    Please put to this topic code your sketch....

  • Sur,

    my node controls two relays, one water pressure sensor and three DS18b20

     code pour controle cave a vin, temp et pression
    // Enable debug prints to serial monitor
    //#define MY_DEBUG
    // Enable and select radio type attached
    #define MY_RADIO_NRF24
    // Enable repeater functionality for this node
    #define MY_NODE_ID 15
    #include <SPI.h>
    #include <MySensors.h>
    #include <DallasTemperature.h>
    #include <OneWire.h>
    #define BARO_CHILD 0 //Child ID for pressure sensor
    #define BAR_SENSOR_ANALOG_PIN 0 // pin for pressure sensor
    #define COMPARE_TEMP 1 // Send temperature only if changed? 1 = Yes 0 = No
    #define ONE_WIRE_BUS 5 // Pin where dallase sensor is connected 
    #define MAX_ATTACHED_DS18B20 16
    #define RELAY_PIN 3 //pin for first relay
    #define NUMBER_OF_RELAYS 2
    #define RELAY_ON 1  // GPIO value to write to turn on attached relay
    #define RELAY_OFF 0 // GPIO value to write to turn off attached relay
    OneWire oneWire(ONE_WIRE_BUS); // Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
    DallasTemperature sensors(&oneWire); // Pass the oneWire reference to Dallas Temperature. 
    float lastTemperature[MAX_ATTACHED_DS18B20];
    int numSensors=0;
    bool receivedConfig = false;
    bool metric = true;
    float lastpression;
    uint8_t DS_First_Child_ID = 4; //First Child-ID to be used by Dallas Bus
    MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
    MyMessage msg(0,V_TEMP);
    void before()
        for (int sensor=1, pin=RELAY_PIN; sensor<=NUMBER_OF_RELAYS; sensor++, pin++) {
            // Then set relay pins in output mode
            pinMode(pin, OUTPUT);
            // Set relay to last known state (using eeprom storage)
            digitalWrite(pin, loadState(sensor)?RELAY_ON:RELAY_OFF);
        // Startup up the OneWire library
    void setup()
    // requestTemperatures() will not block current thread
    void presentation()
        // Send the sketch version information to the gateway and Controller
        sendSketchInfo("Buanderie node", "1.0");
        //present pressure sensor
        present(BARO_CHILD, S_BARO);
        for (int sensor=1, pin=RELAY_PIN; sensor<=NUMBER_OF_RELAYS; sensor++, pin++) {
            // Register all sensors to gw (they will be created as child devices)
            present(sensor, S_BINARY);
    // Fetch the number of attached temperature sensors  
      numSensors = sensors.getDeviceCount();
      // Present all sensors to controller
      for (int i=0; i<numSensors && i<MAX_ATTACHED_DS18B20; i++) {   
         present(i + DS_First_Child_ID, S_TEMP);
    void loop()
      //read water pressure
    int lecture_adc = analogRead(BAR_SENSOR_ANALOG_PIN);
      float pression = ((lecture_adc*5/1024.0)-0.50)/1.7;
      if(pression != lastpression) { 
          send(pressureMsg.set(pression, 2));
      lastpression = pression;
      // Fetch temperatures from Dallas sensors
      // query conversion time and sleep until conversion completed
      int16_t conversionTime = sensors.millisToWaitForConversion(sensors.getResolution());
      // sleep() call can be replaced by wait() call if node need to process incoming messages (or if node is repeater)
      // Read temperatures and send them to controller 
      for (int i=0; i<numSensors && i<MAX_ATTACHED_DS18B20; i++) {
        // Fetch and round temperature to one decimal
        float temperature = static_cast<float>(static_cast<int>((getControllerConfig().isMetric?sensors.getTempCByIndex(i):sensors.getTempFByIndex(i)) * 10.)) / 10.;
        // Only send data if temperature has changed and no error
        #if COMPARE_TEMP == 1
        if (lastTemperature[i] != temperature && temperature != -127.00 && temperature != 85.00) {
        if (temperature != -127.00 && temperature != 85.00) {
          // Send in the new temperature
          send(msg.setSensor(i + DS_First_Child_ID).set(temperature,1));
          // Save new temperatures for next compare
    void receive(const MyMessage &message)
        // We only expect one type of message from controller. But we better check anyway.
        if (message.type==V_STATUS) {
            // Change relay state
            digitalWrite(message.sensor-1+RELAY_PIN, message.getBool()?RELAY_ON:RELAY_OFF);
            // Store state in eeprom
            saveState(message.sensor, message.getBool());
            // Write some debug info
            Serial.print("Incoming change for sensor:");
            Serial.print(", New status: ");

  • Mod

    @lekeb said in 💬 Relay:

    MyMessage pressureMsg(BARO_CHILD, V_PRESSURE);
    MyMessage msg(0,V_TEMP);

    Why are you using the same child ID (since you set #define BARO_CHILD 0)?

  • @gohan Effectively, he will never report any temp reading under ChildID 0. Within presentation() and the send() commands, the "0" is replaced by "i + DS_First_Child_ID".
    But you are partly right, to avoid any misunderstandings wrt. that the statement could also be written as follows:

    MyMessage msg(DS_First_Child_ID,V_TEMP);

  • correct, it makes sense. I will correct this error.
    However Domoticz reads correctly the temperature and links correctly the CHILD ID's, so...

  • Hello everybody !

    I would like to creat a sensor with two relays and two buttons to command this relay direct from the sensor (with actualisation of their stat in domoticz)
    Someone know the code to do this ? I'm a complete newbie on mysensor !

    Thank's a lot !

  • @jonathan-pucel Have a look at the code in this post.

  • Excellent ! It's perfect, thank's a lot rejoe2 !

  • This post is deleted!

  • Hi
    Using Home assistant, and Optimistic set to false in the mysensors config, the switch in homeassistant would turn the relay on, but in the view in homeassistant the flip switch jumped off straight after switching on. It was solved by adding the following line to the sketch, ensuring that hassio knows that the actuator actually have received the command. Not sure if this is a good way of doing it, but it seems to work for me.
    send(msg.set(state)); // Send new state and request ack back
    void receive(const MyMessage &message) {
    // 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");

    if (message.type == V_LIGHT) {
    // Change relay state
    state = message.getBool();
    digitalWrite(RELAY_PIN, state?RELAY_ON:RELAY_OFF);
    // Store state in eeprom
    saveState(CHILD_ID, state);

     // Write some debug info
     Serial.print("Incoming change for sensor:");
     Serial.print(", New status: ");
     send(msg.set(state)); // Send new state and request ack back



  • Hi!

    I would like to control some 230VAC equipment (for now roller shutters), based on inputs from my mysensors sensors (temperature and light). For controller I use domoticz.

    I would like a safe, robust and preferably authorized/lawful solution (I'm in EU/Denmark).

    I came across the following solutions:


    I think the first one and maybe the second one will be authorized/lawful...? However, I have experience only with mysensors and neither z wave nor sonoff...

    Anyone has some experience/thoughts/suggestions to share?


  • Mod

    There are also roller shutters nodes running via zwave if you are looking at a retail solution

  • Thank you @gohan! Retail solution is not the keyword here. What I am searching for is an authorized/lawful (safe) solution.

    I decided to do my own node (mysensors) with a cheap relay module for the arduino. Once I achieve the desired functionality I will change to some more robust hardware. Following your suggestion this could be a z wave roller shutter (e.g. fibaro or qubino).

  • @arrawx said in 💬 Relay:

    Retail solution is not the keyword here. What I am searching for is an authorized/lawful (safe) solution.

    Sorry to comment negative, but your wording doesn't make sense. either you will go for a DIY solution, cheap and illegal (but not necessary a bad solution), or you will purchase a retail solution.
    Retail solution must have the required certificates to allow you to sell. Those are not cheap to get, which also provide the reason for a retail solution to
    be usually fairly expensive

    And also you need Notified Body

    And I know that Cetekom can create certificate for Country Approvals

  • There is a problem with the example code for RelayActuator.ino It is not checking for ACK messages. See the other example called SecureActuator.ino that does this. Without checking for ACK messages my relay gets an ON signal and turns on then immediately thereafter gets an ACK signal for V_STATUS command which is assumed in this example to be a control and the value is "0" so it turns off the relay.

  • Mod

    @slt1 I'm not sure I'm following. RelayActuator.ino does not send any messages, so it should never receive any ack messages. Compare with RelayWithButtonActuator.ino which does send messages, and therefore also checks for ack.

    Could you elaborate on the problem?

  • @mfalkvidd

    For some reason I am now unable to reproduce the issue on the standard RelayActuator.ino example. It was definitely sending ACK requests when I was testing a few days ago. I have subsequently updated MySensors library and also MyController to their latest Snapshot - so perhaps the issue comes up under one of those scenarios.

    The issue around this though is that the example does not report the current status of the relay in the loop. My own sketch was doing so. I guess many people take an example and modify it like I do. Therefore copying the example and adding in the code to send the current relay status periodically means the receive function will not work properly due to the Ack messages received,

    I would then suggest adding a note to the receive function of the relay example sketch to say that "if your node sends messages then you need to check for Ack and discard those messages" - or something along those lines. This will help !

  • Mod

    @slt1 thanks for explaining.

    I'll think about it for a bit but I hope to submit a pull request soon. I'll post here when it is ready.

  • Mod

    @slt1 sending current status won't generate an ack/echo message. So there should not be a need to handle the ack/echo flag. Hardware acks (which are enabled by default) do not trigger the receive function.

    The only case when an ack/echo message will be sent is if the sketch developer explicitly requests an ack/echo by setting the ack parameter in send() to true. If the sketch developer does that, they need to handle the ack/echo message inside the receive function, according to however they plan to handle the ack/echo message.

    My guess is that people set the ack flag to true without understanding what they are doing. I hope to make the documentation slightly less confusing by doing https://github.com/mysensors/MySensors/issues/1103

    mfalkvidd created this issue in mysensors/MySensors

    closed Rename "soft ack" to "echo" #1103

  • @mfalkvidd Thanks - and yes - I did make the assumption that send with ack = true means do a hardware ack. I was unaware that a "software ack" also exists. I read your comment here : https://forum.mysensors.org/topic/3346/discussion-reliable-delivery/17 and what you mention there needs to be made loud and clear in the docs - perhaps some mention in both the message send function and message receive function,

  • Mod

    @slt1 I agree. Made the same mistake and it took me 40 hours of reading documentation and troubleshooting before I realized there was a difference between the two acks.

  • The script for 'Example with button' works perfectly! Thanks for that.
    Has someone a script for multiple Relays with buttons ready to use for me?
    I want to use it in my garden to switch the lights with physical buttons and also control them with Domoticz.

  • This post is deleted!

  • I am having this particular switch to be recognized in "Mozilla WEBTHINGS".

    IS there some issue with having a repeater node and sensors/switches etc attaches to it? .. it sends in the data as it should when I check with MYSController and I can switch it from there with sending "V_STATUS" messages. but no luck so far of getting the sensors appear in WEBTHINGS , every other sensor works fine.

  • // Enable debug prints to serial monitor
    #define MY_DEBUG

    // Enables and select radio type (if attached)
    #define MY_RADIO_RF24
    //#define MY_RADIO_RFM69
    //#define MY_RADIO_RFM95

    #define MY_GATEWAY_ESP8266

    #define MY_WIFI_SSID "SSID"
    #define MY_WIFI_PASSWORD "PSW"

    // Enable UDP communication
    //#define MY_USE_UDP // If using UDP you need to set MY_CONTROLLER_IP_ADDRESS or MY_CONTROLLER_URL_ADDRESS below

    // Set the hostname for the WiFi Client. This is the hostname
    // it will pass to the DHCP server if not static.
    #define MY_HOSTNAME "ESP8266_GW"

    // Enable MY_IP_ADDRESS here if you want a static ip address (no DHCP)
    //#define MY_IP_ADDRESS 192,168,0,0

    // If using static ip you can define Gateway and Subnet address as well
    //#define MY_IP_GATEWAY_ADDRESS 192,168,178,1
    //#define MY_IP_SUBNET_ADDRESS 255,255,255,0

    // The port to keep open on node server mode
    #define MY_PORT 5003

    // How many clients should be able to connect to this gateway (default 1)

    // Controller ip address. Enables client mode (default is "server" mode).
    // Also enable this if MY_USE_UDP is used and you want sensor data sent somewhere.
    //#define MY_CONTROLLER_IP_ADDRESS 192, 168, 178, 68
    //#define MY_CONTROLLER_URL_ADDRESS "my.controller.org"

    // 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
    // Led pins used if blinking feature is enabled above
    //#define MY_DEFAULT_ERR_LED_PIN 16 // Error led pin
    //#define MY_DEFAULT_RX_LED_PIN 16 // Receive led pin
    //#define MY_DEFAULT_TX_LED_PIN 16 // the PCB, on board LED
    #define LWIP_OPEN_SRC whatever
    #define TCP_MSS whatever
    #define LWIP_IPV6 whatever
    #define LWIP_FEATURES whatever

    #include <MySensors.h>
    #include <SPI.h>
    //DHT with autodetection

    #include <dhtnew.h>

    DHTNEW mySensor(5); // ESP 16 UNO 6

    uint32_t count = 0;
    uint32_t start, stop;

    uint32_t errors[10] = { 0,0, 0,0, 0,0, 0,0, 0,0 };

    #define CHILD_ID_HUM 2
    #define CHILD_ID_TEMP 3
    MyMessage msgHum(CHILD_ID_HUM, V_HUM);
    MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);

    void presentation()
    // Send the sketch version information to the gateway
    sendSketchInfo("TemperatureAndHumidity", "1.1");

    // Register all sensors to gw (they will be created as child devices)
    present(CHILD_ID_HUM, S_HUM);
    present(CHILD_ID_TEMP, S_TEMP);


    void setup()
    Serial.print("LIBRARY VERSION: ");

    void loop()
    // show counters for OK and errors.
    if (count % 50 == 0)
    Serial.println("OK \tCRC \tTOA \tTOB \tTOC \tTOD \tSNR \tBS \tUNK");
    for (uint8_t i = 0; i < 9; i++)

    if (count % 10 == 0)

    start = micros();
    int chk = mySensor.read();
    stop = micros();

    switch (chk)
    case DHTLIB_OK:
    #ifdef MY_DEBUG
    Serial.print(mySensor.getHumidity(), 1);
    Serial.print(mySensor.getTemperature(), 1);
    Serial.print(stop - start);

    //send to gateway
    float humidity = mySensor.getHumidity();
    send(msgHum.set(humidity, 1));
    float temperature = mySensor.getTemperature();
    send(msgTemp.set(temperature, 1));


    // -- END OF FILE --

  • I was so happy to have finaly a fonctionnal sketch for my esp8266 gateway whith the DHT22 that i post directly my code.
    I hope that it will help some people.
    based on: https://github.com/RobTillaart/DHTNew/blob/master/examples/dhtnew_endless/dhtnew_endless.ino

  • Hi,
    Trying to go deep on the API and come this this doubt: The second example (with button) the child seems to be declared as "S_LIGHT" and the receiving messages are "V_LIGHT", while the first example seems better suitable for a relay (child as "S_BINNARY" and requests as "V_STATUS").
    I haven't found any "S_LIGHT" or "V_LIGHT" in the API, only "S_LIGHT_LEVEL" and "V_LIGHT_LEVEL". What is the most suitable type for a relay node with a local button?

  • @joaoabs A realy usually has only 2 states, on and off. So I would use S-BINARY and V_STATUS every time.

    A changeover realy also has 2 states so again I would go for binary and status.

    Light_Level is more suited to getting light levels from a sensor or sending a light level to a dimmable light.

  • Contest Winner

    Not sure if it ever has mentioned before, but the first example contains

    // Enable and select radio type attached
    #define MY_RADIO_RF24

    Which results in a compile error

    MySensors.h:287:4: error: #error No forward link or gateway feature activated. This means nowhere to send messages! Pretty pointless.
       #error No forward link or gateway feature activated. This means nowhere to send messages! Pretty pointless.

    It should be:

    // Enable and select radio type attached
    #define MY_RADIO_NRF24

    And then it compiles and works 🙂

  • Mod

  • Contest Winner

    @mfalkvidd I'm in an older version I discovered. Ran across more small differences.

  • @TheoL Sound like a good time to update to the latest version. it is the best yet and very stable.

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