Hi! my Project:
I am using a led strip for light painting. By changing the pixel colors while walking I can paint pictures in real life. Here is a link to the commercial product that inspired me: pixelstick Light painting evolved - YouTube
Currently I am using a programm on my PC to convert images into a 2 dimensional array safed in a .h file. Than I include the .h file into my program, which is circling throw the array row by row and displaying the colors on the led strip.
my Problem:
I have to upload the programm everytime I change the image, this takes up to 90 sec for larger images. Also I am running short on memory. I am already using the arduino due and saving the array in PROGMEM. To safe on memory I have already an option to safe a color in 8bit instead of 32bit, but that decreases the quality of the picture :(.
my Plan:
I would like to read the Images from a sd card. I tryed to find a library that could help me with that but all librarys I have found could just read from an sd card to paint it on an TFT or OLED display. One (JPEGDecoder) was able to convert an 2 dimensional array to an jpeg image but that is the wrong direction for my case :/.
The Filetype of the image should be a standard.
Thanks for reading I am looking forward to read your replies.
Than I include the .h file into my program, which is circling throw the array row by row and displaying the colors on the led strip.
If the code can read the data from an array in PROGMEM, or an array in SRAM, it could just as easily (though not necessarily as fast) read the data from a file on an SD card.
Or, it could read the data live from the Serial port.
What does not make sense is to talk about reading an image "row by row". JPEG data is certainly NOT stored row by row.
Bitmap (BMP) files ARE stored in a left to right, top to bottom, way.
But, if you already have a process to convert an image to text in a .h file, saving that text to a .txt file on an SD card would be trivial. Reading the file on the SD card, and using the data as though it had been read from PROGMEM or SRAM would be relatively simple.
Post the code you have now, and an example of the .h file.
Thanks for the answer.
I would like to skip the step of converting my images to .h files. It makes it a lot easier to create new images and put them on a sd card without a special Programm to convert them first. It would make it possible to change and edit the images on my smartphone and I wouldn't need to take a laptop to my photo location.
I am currently looking into the BMP file format and my first test are working.