Logitech MX518 mouse

Logitech MX518 Legendary, model number MU0053 (G-series refresh), black version ("Nightfall").

Very lightly used (almost unused?) but not working when received, enumerating with VID 0, PID 0.

I hate these screws under feet. Here feet have also two layers - external and some kind of foam and when removing top foot I've left this foam, probably bad decision.

Watch out for the tape that is connecting switches from top part of the shell.

HERO Hg11 optical sensor.

STM32L100R8T6

• 64 kB FLASH
• 8 kB RAM
• 2 kB EEPROM (pretty rare from STM32)
• USB
• LQFP64 - seems like there would be many unused pins
• currently not recommended for new designs

Failure: broken DATA- USB cable line.

Cable usually breaks near the plug or near the mouse itself, but cutting it blindly would be wasteful, especially considering fancy mounting inside the mouse (H-shaped injection holding the cable near the screws).

I've measured DATA- line capacitance from both ends and it turns out it was very low (~17 pF) near USB plug. This plug did not look well anyway, with two pins sticking out, so I've cut cable few centimetres from the plug.

Overall cable quality seems fine, with decent shielding, few (nylon?) threads between the lines and thread inside each line.

I've used plug from some old Apple Lightning (probably knockoff) cable, wrapped with few layers of different sizes heatshrink tubes working as strain relief plus some epoxy glue. This should be more solid than original.

Mouse feet are slightly warped, but I believe they should still serve well. In worst case, as this is quite popular brand and model, replacement sets are available and not that expensive, starting from $1.50 if you don't mind waiting for shipping from China.

In hindsight, I could probably avoided opening mouse altogether if I would have thought of measuring cable capacitance first.