Tail light HID protocol

HID protocol description

Tail-light update

Steps to update the tail-light:

• Connect to mouse HID device with Usage=0212 and UsagePage=FF07.
• Send a feature report with ByteLength=73 with the following header:

FeatureReport[0] = 0x24; // ReportID 36
FeatureReport[1] = 0xB2; // magic value
FeatureReport[2] = 0x03; // magic value
FeatureReport[3] = red;
FeatureReport[4] = green;
FeatureReport[5] = blue;

How to reverse-engineer the protocol

It's possible to reverse-engineer the IntelliMouse USB HID protocol by installing USBPcap and Wireshark.

Steps:

1. Open Wireshark with USBPcap plugin.
2. Open "Microsoft Mouse and Keyboard Center" app.
3. Change tail-light color.
4. Observe USBHID SET_REPORT Request packages with ReportID=36 and ReportType=Feature that adhere to the format described above.

The feature report also contains a number of other non-zero bytes. I don't know if they carry a meaning or are just uninitialized memory.