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Comment by unwind

11 days ago

Very interesting! Seems like a Bluetooth-connected display is kind of rare.

This part:

The one thing I’m left scratching my head over is the length field. If I have 0x20 bytes of image data to send over, I actually need to put 0x10 into that field.

Made me think the protocol simply assumes at least 2 bytes will always be used, so it transmits the length using the unit of 16-bit "words" instead of bytes. That would not be unheard of, and is kind of smart even.

It's kinda weird since the payload seems to be (repeat:u8 + rgb565:u16)*, so always multiples of three bytes, not two.

Given how this is sort of software is usually written, my guess would be they originally didn't have the RLE encoding and were just sending (rgb565:u16)*. That'd explain it.

Not sure if same vein/counts, Monocle/Frame is bluetooth based

  • I have a Monocle! It's much worse than this device. The battery only lasts about an hour, and you can't do real images.

    • I have a Frame and it’s not so great, the prism interferes too much with your vision. You can do images on the Frame. I’m optimistic that Brilliant Labs latest iteration might be better - Halo. They are great at being open source and open design.

      Probably the leading current product if you want HUD Bluetooth glasses are Even Realities G1s but those aren’t going to do images however they have very crisp and useable monochrome displays for text.

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