Show picture controlled from Arduino

Software Development
1

Hello,

I have imported a couple pictures. The are numbered 0 to 10.
Is it posible tho load a picture with a command from the Arduino.
This is my code but it not working:

/* load picture and display */
void updatePicture(int picture_nr)
{
  Serial2.print("p0.pic=\""); // Changing the value of pic
  Serial2.print(String(picture_nr));
  Serial2.print("\"");
  Serial2.write(0xff);  // We always have to send this three lines after each command sent to the nextion display.
  Serial2.write(0xff);
  Serial2.write(0xff);
}

Or is it posible to load a picture from the sd card. I have a 4.3" P version
Thanks for any help.

2

Here’s how I do it:

	const char* nextionEnd = "\xFF\xFF\xFF";
	const char* nextionQuoteEnd = "\x22\xFF\xFF\xFF";
	const char* pageSync_b6_Char = "pageSync.b6.pco=0";

	SerialPrint(pageSync_b6_Char);
	SerialPrint(nextionEnd);

Or similar code where the id changes:

SerialPrint(pageIndex_t7_Char);
SerialWrite(0x22);
SerialPrint(newIndexSize, 4);
SerialPrint(nextionQuoteEnd);

SerialPrint and SerialWrite are just wrappers around Serial.print and Serial.write which allow different serial ports to be used.

3

Couple tips for readability:

You can include quotes (and backslashes) in a string by preceding them with a backslash. F.ex.

Serial.print("Arduino says \"Hi\". ");
=> Arduino says "Hi".

Serial.print("Some path: C:\\Hello\\World");
=> Some path: C:\Hello\World

Additionally, if you want the ordinal of a single character (a.k.a. just one number, not an array of chars/numbers), you can use single quotes (more details):

int quotes = '"';
Serial.print("ASCII code of the character \" : ");
Serial.print(quotes);
=> ASCII code of the character " : 34

This should be more readable than using "\x22".

Kind regards,
Max