disclaimer: i received this mouse for free. not a review. just sharing info and pictures for those who are curious.
the logitech g102 has a new optical sensor (i.e. led illuminated, image correlation) that is not made by avago/pixart
the sensor is connected to the main pcb with some weird surface-mount soldering. not sure what it's called.
illumination is external as you can see.
the lens is sort of clipped onto the sensor block. there is a little bit of wiggle possible. i doubt anyone will complain about "lens rattle" like for some of the 3366 mice, but we'll see.
some quick probing around with a multimeter and an oscilloscope reveals most of the pins' functionalities:
(1 is bottom right, closest to the mcu. numbers go counter clockwise)
mousetester looks unlike anything i've ever seen.
Originally Posted by qsxcv
at low speeds there are discrete steps. at high speeds eventually it gets to something above 10000fps. for now, i'm too lazy to figure out exactly
i was quite confused by the discrete steps, but here's a plausible explanation
it appears what is going on is that for moderate speeds, the framerate is continuously adjusted such that the amount of motion in a frame is nearly constant.
i suspect this is a very low power sensor which will eventually be used in a wireless mouse
well my hunch about the continuous framerate was sort of right. hooking up a wire to the led cathode gives a direct view of the timing of the frames:
when not in motion, the sensor runs at about 1000Hz.
the sensor frames are not synchronized to the usb frames, which can be easily shown by taking a few snapshots:
Warning: Spoiler! (Click to show)
if you don't touch the sensor for about 100 seconds, it goes into a 50Hz rest mode. I'm not sure whether there are deeper rest modes though.
k so what happens when you move it?
the increasing intensity reflects increased density of the led's toggling. i.e. higher framerate
quite surprising how sporadic it is. not sure if this is a good or a bad thing. i would prefer to see either a constant framerate or at least one that always has periodic timings, but it's possible that this is intentional. i don't know.
but anyway, unlike the 3310, 3360/3366, etc... the framerate isn't adjusted by entering different modes with predefined framerates. or so it appears at least
the maximum framerate is something around 12kHz
some initial info about the spi:
6 bytes of communication every 1ms.
spi runs at 8MHz