May 23rd, 2015

Working out the 4D systems uOLEDs has been an incremental process, solving one issue at a time. I finally got the screen to work in a way that is more or less satisfactory. There are a few minor details that need to be ironed out but the major the technical issues have been resolved. I will write up some documenation here for prosperity.

Workshop 4, the software program that allows user to control the screen, is free and you can work with it with or without writing codes (4DGL), but the documentation is a bit sketchy and leaving someone who is new to the technology to do a lot of guesswork.  For example, working out the acceptable file formats seem to be a trial-and-error process (guessing mostly Windows-based formats).

Previously, I started using VISI Genie which is the mode that does not require writing 4DGL. The video loaded but would only play once. There is no mechanism for loading. So I needed to get into VISI that allows users to write but with some user graphic interface. I also found a great reference online for doing exactly what I needed to do, thanks to a fan of MYST who posted a tutorial on SparkFun.

In the midst of sorting the looping issue out, the following problems and quirks also cropped up:

Acceptable file formats seem to be .wmv, gif, and .avi. WMV files are generally to compressed and played too slowly (not at the specified framerate). GIF plays at the specified framerate but it is difficult to get a satisfactory image quality with the compression (or what the settings seem to allow anyway).  AVI seems to be the best bet, but the trouble is I have limited options for exporting to an .avi working on macs. AVI as I understand is simply a container, creating an .avi file with a codec Windows can’t read (e.g. .mp4) also leads the file being unacceptable. So some more testings are needed. The same goes for framerate. At the moment, the files are converted through an online convertor.

The uOLED’s aspect ratio is 4:3 which doesn’t fit more recent video files which are 16:9. The test file plays in a letterbox arrangement however instead of black bars, the green text (part of the instructions to the screen) is showing through. I tried loading a black .jpg onto the background and switching transparency off, neither of which works. I may have to resort to other work-around methods.

Workshop 4 only works with uSD that is formatted with FAT16 (not FAT32), which means the card must be 2GB or less (probably hard to find these days). A card bigger than 2GB needs to partition before it can formatted with FAT16.

Below is a video showing a mock up of a screen in a box. Of course the circuitry needs to be worked out (to power the screen and the leds using the same power source?) as well as the physical wiring and installation into the tiny box.

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