Calling custom functions

ESPHome
1

I’m trying to figure out how to call a custom function in a switch.
I have a custom uart polling component where I pass some sensor values that it reads. I also want to be able to send some uart commands that are implemented in a function in the custom component.
I can’t figure out how to do this. Now I’m a hardware guy and know enough software to be dangerous! :slight_smile:
My switch is define like this:

switch:
  - platform: gpio
    pin: GPIO26
    id: generic_switch
    name: 'on_off_mppt'
    on_turn_on:
    - logger.log: "Switch on"
    - lambda: "id(mppt_jb).send_CC_ON()"
    on_turn_off:
    - logger.log: "Switch off"

it’s complaining about no send_CC_ON being defined.
my custom component is instantiated here:

custom_component:

- id: mppt_jb
  lambda: |-
    auto my_mppt2 = new BlueSkyWiFi(id(uart3),id(Bvol),id(PVvol),id(Bcur),id(Bwatts));
    App.register_component(my_mppt2);
    return {my_mppt2};

My customer component looks like this:

class BlueSkyWiFi : public PollingComponent, public UARTDevice
{
  Sensor *xsensor1{nullptr};
  Sensor *xsensor2{nullptr};
  Sensor *xsensor3{nullptr};
  Sensor *xsensor4{nullptr};
  Switch *xsw1{nullptr};
  mppt_controller myMppt;
  int count;
  int last_milli;
  int new_milli;

public:
  BlueSkyWiFi(UARTComponent *parent, Sensor *sensor1, Sensor *sensor2, Sensor *sensor3, Sensor *sensor4) : UARTDevice(parent), xsensor1(sensor1), xsensor2(sensor2), xsensor3(sensor3), xsensor4(sensor4) {}

  byte buf[32];
  void init_count() {
    this->count=0;
    this->last_milli = 0;
  }

  void send_CC_ON(){
      write_byte(0xAA);
      write_byte(0xCC);
      write_byte(0x02);
      write_byte(0x00);
      write_byte(0x00);
      write_byte(0xCE);

  }

How do I get it call a function from like a switch action. I’m either missing something simple or I’m going about it the wrong way!

Thanks,

Jim

2

I’m no ESPHome wizard, but I believe you might have to define send_CC_ON as an ESPHome service in your YAML file, and possibly in your C++ code.

3

Clearly I’m not a wizard either! I would have thought that because the custom component is already registered and the function is a public function, it would know about that function.

4

I’m going to bump this as I still haven’t figured it out yet and I just went back to revisit this!, Any help/examples would be appreciated… :slight_smile:

5

Try using this as your on_turn_on function:

 - lambda: |-
 static_cast< BlueSkyWiFi*> (id(mppt_jb).get_component(0))->send_CC_ON();
2 Likes
6

Thanks! That did work. I probably should dive down deep to figure out why that works and would I have any chance of finding that on my own!! :grinning_face_with_smiling_eyes:

7

You have to look at the API docs to see what backend functions you have available.

https://esphome.io/api/custom__component_8h_source.html
https://esphome.io/api/classesphome_1_1custom__component_1_1_custom_component_constructor.html

Since there is only one component for that ID, you use component 0. You then have to cast it to whatever custom component Class is assigned to that component.

8

Another thing you can do is have a look at the generated build files that esphome creates from the yaml, specifically main.cpp. Those files show up in the directory

 /config/esphome/.esphome/build/<your project name>/src

You will see how custom components are instantiated there. Looking at this file will give you a better understanding of the inner workings of esphome.

9

I was playing around and found another maybe simpler way of accomplishing this by setting up your class variable my_mppt2 as global instead of localized under the custom component instantiation.

What you do is add this line after your class definition in your header file:

BlueSkyWiFi * my_mppt2;

Then when you assign the class in the custom component, you simply remove the “auto” definition from the instantiation, which will assign to the previously globally defined my_mppt2 variable above.

my_mppt2 = new BlueSkyWiFi …

So what that means then, is in your other lambda functions you are able to access your class functions using:
my_mppt2->send_CC_ON();

I don’t see any minuses from doing it this way so far. Works fine in my testing.

3 Likes
10

I just want to say that this is the only clean solution I’ve found to have a global custom class on which you can call methods.