And I don't know why the code looks like this, I added it according to 
the format of the website.

Cliff W. wrote:
> Global variables used 3046 bytes
Thats the actual problem: you have one or some big (text) arrays or 
pictures or something else with need for RAM in your code.

Attach your code as a file, then its easy to say where the problem is 
located.

> And I don't know why the code looks like this
Some kind of rendering problem since the last change of the forum 
software.

I added the code file as an attachment.

Lothar M. wrote:
> you have one or some big (text) arrays
As expected: those "constant" strings are located in RAM. Each of the 44 
strings is over 90 chars long and so its easy to see, that they sum up 
to nearly 4k. The whole magic is here, that the compiler does some 
optimizations to reduce that size to only 3k...

flip wrote:
> transfer these strings into program mem.
Thats the best way, because even when you keep them in RAM they are in 
the program mem also, as they are needed to initialize the RAM at 
startup.

But I would not stupidly transfer those strings to FLASH/PROGMEM. 
Instead I would look for similarities and doubles and place them only 
one time in the FLASH/PROGMEM.

So the strings

"ST<{\"cmd_code\":\"set_enable\",\"type\":\"widget\",\"widget\":"

and

"ST<{\"cmd_code\":\"set_image\",\"type\":\"image\",\"widget\":"

are used throughout the whole program several times. Its enough to 
define them only once.
Or even more: those two parts of that strings are the same:

"ST<{\"cmd_code\":\"set"

and

"\",\"type\":\"widget\",\"widget\":"

so only the two parts "enable" and "image" must be changed.

>
> So the strings
>
> "ST<{\"cmd_code\":\"set_enable\",\"type\":\"widget\",\"widget\":"
>
> and
>
> "ST<{\"cmd_code\":\"set_image\",\"type\":\"image\",\"widget\":"
>
> It's enough to define them only once.

I think what you are saying can be implemented, except that I need to 
modify the code to add loops or arrays? I'll try following your 
direction.

Cliff W. wrote:
> except that I need to modify the code
For sure.

> to add loops or arrays?
Why loops?

Try it somehow like that:

1

char str_enable[] = "ST<{\"cmd_code\":\"set_enable\",\"type\":\"image\",\"widget\":";

2

char str_image[]  = "ST<{\"cmd_code\":\"set_image\",\"type\":\"image\",\"widget\":";

3

:

4

:

5

    Serial.print(str_image);

6

    Serial.println("\"image2\",\"image\":\"circle\"}>ET");

7

:

8

:

9

    Serial.print(str_enable);

10

    Serial.println("\"button1\",\"enable\":false}>ET");

11

:

12

:

13

    Serial.print(str_image);

14

    Serial.println("\"image1\",\"image\":\"circle\"}>ET");

15

:

16

:

17

    Serial.print(str_enable);

18

    Serial.println("\"button2\",\"enable\":false}>ET");

19

:

20

:

Of course also you cold simply look for the F() macro and use it in the 
Serial.println() function call.

Ok, thanks for your patience, I tried the F() method and managed to 
upload it to the board! I'll try to make the code shorter later too.