wled json api over serial communication problems

[miwied]

Hello guys and especially @Aircoookie !

my setup:

I have a "main mcu" (which is a esp32) that shall control the "wled mcu" (esp8266 d1 mini) via serial communication.
I use the WLED-0.13.0-b6 version. I compiled it myself and changed the Serial baudrate to 921600, hoping to improve serial communication.

current state:

I experimented with the json api over serial now for about 5 days, and after some success I stuck on an annoying problem / (bug?).
The communication itself works but not ALL JSON objects arrive at the wled mcu.
I've read about a "verboseResponse mode" which sometimes blocks the serial input, but I think that this is not the case with my setup.

the problem:

Unfortunately, despite successfully sending a json package, sometimes the expected change does not occur. (The package doesn't seem to be received).

demo / test code

Here you can see a very simple demo code which I wrote for sending the JSON objects:
https://github.com/miwied/wled-json-api-over-serial

Do u guys have some ideas what the problem could be and how I could fix it?
I've already had read #1173 and #1146 but unfortunately it didn't help me.

[Aircoookie]

Hey!
Is the color what is not applied correctly?
It seems like your code is sending e.g. {"on":true,"bri":110,"seg":[{"col":[255,255,255]}]} while it should be {"on":true,"bri":110,"seg":[{"col":[[255,255,255]]}]} (one more nested array for the color).
Otherwise, your 192 byte static JSON buffer is kind of small, once you want to send larger messages with multiple segments you need to increase it (see https://arduinojson.org/v6/assistant/ which tells you the size you need depending on what JSON you want to send)

[miwied]

@Aircoookie Thank you for your prompt reply!

Is the color what is not applied correctly?

Nothing is applied at all when this error occurs. Nothing changes.

https://arduinojson.org/v6/assistant/

Indeed I was using this tool for this sketch.

If I copy ur JSON object

{"on":true,"bri":110,"seg":[{"col":[[255,255,255]]}]}

and then paste it into the assistant, the code is exactly the same as I used.

StaticJsonDocument<192> doc;

doc["on"] = true;
doc["bri"] = 110;

JsonArray seg_0_col_0 = doc["seg"][0]["col"].createNestedArray();
seg_0_col_0.add(255);
seg_0_col_0.add(255);
seg_0_col_0.add(255);

serializeJson(doc, output);

[miwied]

Problem solved!

( @Aircoookie )
I can't exactly say why, but when I used the HardwareSerial instead of the SoftwareSerial, the communication works without any problems and without any input lag (exactly what I wanted). This solved the problem for me :)

Checkout my simple demo code if you want to use the json api over serial too:
https://github.com/miwied/wled-json-api-over-serial

[Aircoookie]

Nice! SoftwareSerial is only suitable for very slow baud rates, definitely not 921600 in most cases. You should always use HW serial if possible, and in case SoftwareSerial is indispensable, use the lowest possible rate.