For my ledclock I’ve implemented a little datatransfer. But I want to have a gradient on my clock. My data transfer implementation is quite simple, first the command leddata than it will follow with all the data.
To achieve this without to much effort I did the following:
- Open gimp and create a file of 60×1 pixels.
- Select the gradient tool
- Export the file as 24 bits bitmap, 8 bit Red 8 bit Blue 8 bit Green to /tmp/test.bmp
- Note that bmp orients the data in the file as gbr instead of rgb.
- tail -c -180 /tmp/test.bmp > /tmp/leddata_test
- A bitmap is constructed of a header and then rgb data. In this case I have 60 pixels of 1 byte per color so 60 * 3 bytes represent the gradient.
- With the use of tail -c -180 I start counting backwards 180 bytes which results in the gradient data in /tmp/leddata_test
- open cutecom
- send the command leddata
- use cutecom to transfer the data as plain and bobs your uncle