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Comment by freehorse | Hacker News Reader

Is position estimation from the signal that accurate for that?

They don't mean the absolute real distance between dongle and mouse.

They mean the mouse communicates an absolute position (relative to some arbitrary 0,0 the mouse decides upon) instead of a relative direction.

Dongle can then take latest coord packet and diff it against previous coord packet to get a relative coord to pass via HID to the system.

If the RF packets are lost, some latency occurs but the dongle still has the previous mouse coord and can make a fairly accurate correction once a packet gets thru (get's from A to D, but might skip points B+C).

What happens with that "absolute position relative to some arbitrary 0,0 picked by the mouse" when the user picks the mouse up off the table/pad/etc. and repositions it (i.e., they hit the edge of the pad and now "re-center" to continue moving left (or right) on screen). The mouse loses its 0,0 point reference as soon as it is picked up.

It could send a "reset 0,0" packet of some form in this case, but now reception of that packet becomes critical to continuing to properly communicate motion to the attached computer.

> It could send a "reset 0,0" packet of some form in this case, but now reception of that packet becomes critical to continuing to properly communicate motion to the attached computer.

And those "how I would have designed a wireless mouse protocol" guys are back at the square one.

That's not how mouse input works though, right? If I move my mouse cursor to 10,10, and then pick up the mouse and set it down somewhere else, it's still at coordinates 10,10. You don't need the mouse's physical absolute position, but just the cursor position (which is the sum of all the relative movements)

> That's not how mouse input works though, right?

No, mouse input data does not work that way.

My reply was referring to @tehbeard's suggestion that the mouse could be modified to send absolute coordinates instead, and I was pointing out a reason why that modification would not work out so well.

That sounds like a software problem to me, not one that requires a hardware solution. There is nothing in what you describe that cannot be performed through bluetooth packets.

I am not sure which dongles make these corrections, but my experience with dongles is worse than bluetooth. Typically, a mouse is very close to the bluetooth antenna of a computer, and I have not really experienced any sort of connection issues due to missing packages etc. In contrast, I have had tons of issues with usb dongles due to usb interference.

No, mice sensors are far from being SoTA linear encoders. They return approximate instantaneous movements somehow when read request is received. Mouse controller chips(USB or RF or Bluetooth) pack and report up the movements, that's it.

(psa: none of Chinese ADNS-2610 clones have the raw pixel output debug command. Maybe security implications or maybe something else, either way, mouse-as-microscope hacks don't work on sensors extracted from e-wastes)

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