I have a gate based on esp2866, wemos mini board. There are few gpio outputs on it. To implement additional features, such as an inclusive button and status LEDs, I had to connect a gpio expansion board via I2C. I took a PCF8574 based board. For the operation of the button and indication through it, the sources had to be slightly changed, the patch for version 2.4.0 is attached in gist.

Example sketch code:

#define MY_DEFAULT_LED_EXT 1
#define MY_INCLUSION_MODE_FEATURE
#define MY_INCLUSION_BUTTON_FEATURE
#define MY_INCLUSION_MODE_DURATION 10

#include <MySensors.h>
#include <core/MyInclusionMode.h>
#include <PCF8574.h>

const uint8_t scl_PIN = D1;
const uint8_t sda_PIN = D2;
const uint8_t led_device[4] { 2U, 3U, 6U, 4U };
const uint8_t btn_device[4] { 0U, 1U, 5U, 7U };
PCF8574 expander(0x22, sda_PIN, scl_PIN);

void setup() {
  Wire.begin(sda_PIN, scl_PIN);
  Serial.begin(115200);
  while (!Serial) delay(50);
  
  for (uint8_t i = 0; i < 4U; i++) {
    expander.pinMode(led_device[i], OUTPUT);
    expander.digitalWrite(led_device[i], HIGH);
    Serial.printf("Init LED expander: %u/%u\n", (uint16_t)i, (uint16_t)led_device[i]);

    expander.pinMode(btn_device[i], INPUT);
    expander.digitalWrite(btn_device[i], HIGH);
    Serial.printf("Init BTN expander: %u/%u\n", (uint16_t)i, (uint16_t)btn_device[i]);
  }
  expander.begin();
  ledsSetCb(
    [=](uint8_t & state) { expander.digitalWrite(led_device[1], state); },
    [=](uint8_t & state) { expander.digitalWrite(led_device[2], state); },
    [=](uint8_t & state) { expander.digitalWrite(led_device[3], state); }
  );
  inclusionSetCb(
    [=]() { return (expander.digitalRead(btn_device[0], true) == LOW); },
    [=](uint8_t & state) { expander.digitalWrite(led_device[0], state); }
  );
}

void loop() {}

I2C extender

C ++ templates work great, the main thing is not to use class->virtual and RTTI. I write C ++ fluently, it's easier for me.
Thanks for your reply and sorry for my "bad" english.

Yes, I found
It may be useful for those who might come across this issue later:

Git MYCONTROLLER repo

Code for sending RSSI from loop function.
It is not necessary to announce (present) the RSSI sensor.

                    MY_CRITICAL_SECTION {
                        char *buff = new char[18]{};
                        (void) snprintf(buff, 17, "rssi:%d", rssi);
                        reportMsg(getId(), V_VAR5, buff);
                        delete [] buff;
                    }

small fix of the patch, removed "contact bounce" in the inclusive button.

I have a gate based on esp2866, wemos mini board. There are few gpio outputs on it. To implement additional features, such as an inclusive button and status LEDs, I had to connect a gpio expansion board via I2C. I took a PCF8574 based board. For the operation of the button and indication through it, the sources had to be slightly changed, the patch for version 2.4.0 is attached in gist.

Example sketch code:

#define MY_DEFAULT_LED_EXT 1
#define MY_INCLUSION_MODE_FEATURE
#define MY_INCLUSION_BUTTON_FEATURE
#define MY_INCLUSION_MODE_DURATION 10

#include <MySensors.h>
#include <core/MyInclusionMode.h>
#include <PCF8574.h>

const uint8_t scl_PIN = D1;
const uint8_t sda_PIN = D2;
const uint8_t led_device[4] { 2U, 3U, 6U, 4U };
const uint8_t btn_device[4] { 0U, 1U, 5U, 7U };
PCF8574 expander(0x22, sda_PIN, scl_PIN);

void setup() {
  Wire.begin(sda_PIN, scl_PIN);
  Serial.begin(115200);
  while (!Serial) delay(50);
  
  for (uint8_t i = 0; i < 4U; i++) {
    expander.pinMode(led_device[i], OUTPUT);
    expander.digitalWrite(led_device[i], HIGH);
    Serial.printf("Init LED expander: %u/%u\n", (uint16_t)i, (uint16_t)led_device[i]);

    expander.pinMode(btn_device[i], INPUT);
    expander.digitalWrite(btn_device[i], HIGH);
    Serial.printf("Init BTN expander: %u/%u\n", (uint16_t)i, (uint16_t)btn_device[i]);
  }
  expander.begin();
  ledsSetCb(
    [=](uint8_t & state) { expander.digitalWrite(led_device[1], state); },
    [=](uint8_t & state) { expander.digitalWrite(led_device[2], state); },
    [=](uint8_t & state) { expander.digitalWrite(led_device[3], state); }
  );
  inclusionSetCb(
    [=]() { return (expander.digitalRead(btn_device[0], true) == LOW); },
    [=](uint8_t & state) { expander.digitalWrite(led_device[0], state); }
  );
}

void loop() {}

I2C extender

Yes, I found
It may be useful for those who might come across this issue later:

Git MYCONTROLLER repo

Code for sending RSSI from loop function.
It is not necessary to announce (present) the RSSI sensor.

                    MY_CRITICAL_SECTION {
                        char *buff = new char[18]{};
                        (void) snprintf(buff, 17, "rssi:%d", rssi);
                        reportMsg(getId(), V_VAR5, buff);
                        delete [] buff;
                    }

Many thanks to all who answered, regarding MyController I think I will have to look at the source code, in which topic and with what identifier it expects a message about the RSSI evel.

@Clone-Tv said in Where to send messages about battery charge and signal strength?:

message.sender

Thanks for the clarification about message.sender, but then it is not entirely clear why this is used to receive messages? In essence, this should create a regeneration loop of messages ...

Unfortunately, it was not possible to deliver the RSSI level as applied to the MyController interface. The data itself is of course sent and received, but there is no display in the corresponding column. I used the S_SOUND and V_LEVEL identifiers.

Here's a screenshot of where it should be, but it's not there

Do I understand correctly that if (message.sender == 1) is a broadcast message? and it is sent to all nodes at once?

https://github.com/mfalkvidd/Arduino-MySensors-ESP8266-RFM69-Gateway/blob/030be620d45f2fd6cf02bc3633879e8bf35f7ef0/Arduino-MySensors-ESP8266-RFM69-Gateway.ino#L122

C ++ templates work great, the main thing is not to use class->virtual and RTTI. I write C ++ fluently, it's easier for me.
Thanks for your reply and sorry for my "bad" english.

If I send a message with a sensor ID of NODE_SENSOR_ID, I get the following duplicate message errors:

reportMsg(NODE_SENSOR_ID, I_SIGNAL_REPORT_RESPONSE, static_cast<uint16_t>(rssi));

errors:

951492 !MCO:PRO:RC=1
951525 !MCO:PRO:RC=1
951558 !MCO:PRO:RC=1
.. more ..

Everyone a good day.

Where to send messages about battery charge and signal strength? they are not visible in the corresponding fields of MyController.
Explain the topology of sending RSSI system messages and battery level.

Who initiates the request for battery charge and signal strength? Or does the sensor send itself at its own discretion? It seemed to me that there are the following tags: In and Out, so this is all the same dialogue on demand?

I am sending data something like this:

reportMsg(getId(), I_SIGNAL_REPORT_RESPONSE, static_cast<uint16_t>(rssi));

....

template<typename T>
void reportMsg(const uint8_t & id, const mysensors_internal_t & tag, const T & val) {
    _sendRoute(build(_msgTmp, GATEWAY_ADDRESS, id, C_SET, tag, false).set(val));
}

but I don't see the data .. something goes wrong. The same story with battery power, I send data from loop, without external request. Is it correct?

If you press the InclusionMode button and hold it for 10 seconds, the device will restart. In general, typical behavior for many Internet devices.
The patch is attached link.

Strange, but the forum does not allow you to upload anything other than pictures ..

It would be nice to see this in the main code of the repository. So that when updating the version, do not apply the patch separately