While tinkering with ESP8266/ESP32 projects and have ran aground and need some help from

Electronics
, ,
1

While tinkering with ESP8266/ESP32 projects and have ran aground and need some help from the comunity.
I am trying to send a packet that consists on an array of 6 by n parameters from a mobile to an ESP8266/ESP32.
I have been looking at JSON but cannot make sense of it can anyone provide any tips or point me to some reading material.
I have managed to send sensor data to an SQL db via PHP from an ESP8266/ESP32 via POST but cannot make sense of sending data to the ESP8266/ESP32.
Thank you.

2

You would need to tell us for a start which Dev environment you are using
Arduino, Lua or Micropython? Then the right people might help. It’s also worthwhile to post up more info on what you have done.

3

Thanks for the quick reply Richard.
I am using App inventor on the mobile side and arduino env on the ESP side.

I have been thinking that I could do it with the html headers but my data size changes. Array can be 6 by 1, 6 by 2… 6 by n depending on user input and I thought that with html post you have to stick with a fixed structure.

4

As in you have to preallocate a buffer for them to go into? It depends on the framework. I don’t know the Arduino one - I use Lua for my ESP8266 stuff, but it normally gives you a web server and then callbacks for blocks of data. Further, you can have streaming JSON engines that will hook into that - Lua for example has SJON - so Arduino will have a similar library.

If you can do an AJAX post (Content-type: application/json) instead of a normal form post (which has to be form encoded, and this complicates things), then you can feed the data straight into that streaming json library and get a structure out of it that you can use. Again, I don’t know how Arduino does it, in Lua it just comes up as tables of tables.

5

Thanks Richard, can you point me to any literature/tutorials or implementation examples so that I can port them to arduino/App Inventor

6

Maybe this? https://www.youtube.com/watch?v=Edbxyl2BhyU

7

Will do. Thanks Richard.

8

Tonight I managed to get the server to acknowledge the client connection (might have a server parsing issue)… time to have a look at you video… thanks