Any way to build up a dictionary / json object of sensor values in esphome?

Question

I am trying to build up a dictionary / json object of sensor values in esphome. I have a sensor that sends me key / value pairs (e.g. one sensor reading could be { “temperature“: 25.1 }, another one could be { “speed“: 50.1 } and so forth) in very high frequency (milliseconds). What I would like to do is to collect data for these key / value pairs for a certain time span, for simplicity say ten seconds, and only then take the dictionary and post it to a web service. It would also somehow combine the readings for the same key if sent multiple times within the ten seconds time span for example by averaging them out, using a filter or whatever. So the final dictionary to be posted to the web service would then look like

{
    “temperature“: 26.3,
    “speed“: 52.5,
    …
 }

How could I achieve this - any idea / proposal?

Thanks and best regards

Answer 1

Dear stackoverflow community,

I found a solution to this issue. I am now using a global variable in esphome. This can be defined as follows:

globals:
  - id: "my_dict"
    type: std::map<std::string, std::string>

With this, I have a global map which I can use to store the key / value pairs. Adding a new key / value pair via a lambda works as simple as shown in the following (where in this example, the key is stored in the variable key and the value is stored in the variable value:

   lambda: |-
      id(my_dict)[key] = value;

Every ten seconds, I post the dictionary content to the web service and then clear the dictionary again:

interval:
  - interval: 10s
    then:
    - http_request.post:
        url: "https://<URL>"
        json: |-
          for ( auto item : id(my_dict) ) {
            root[item.first] = item.second;
          }
    - lambda: |-
        id(my_dict).clear();