Back to Home11/13/2025, 3:32:24 AM

On USB HID, Keyboard LEDs, and device emulation (2024)

transpute
46 points
3 comments

Mood

thoughtful

Sentiment

positive

Category

tech

Key topics

USB HID

device emulation

hardware hacking

Debate intensity20/100

The article explores the intricacies of USB HID, specifically focusing on keyboard LEDs and device emulation, providing insights into low-level hardware interactions.

Snapshot generated from the HN discussion

Discussion Activity

Light discussion

First comment

3h

Peak period

3

Day 1

Avg / period

3

Comment distribution3 data points

Based on 3 loaded comments

Key moments

  1. 01Story posted

    11/13/2025, 3:32:24 AM

    6d ago

    Step 01
  2. 02First comment

    11/13/2025, 6:48:51 AM

    3h after posting

    Step 02
  3. 03Peak activity

    3 comments in Day 1

    Hottest window of the conversation

    Step 03
  4. 04Latest activity

    11/13/2025, 5:48:27 PM

    5d ago

    Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (3 comments)
Showing 3 comments
jmull
5d ago
1 reply
Glad this popped up here. I've been low-grade tinkering with some USB things and this kind of info is really helpful for getting my bearings.
transpute
5d ago
Found while seeking Linux laptop emulation of USB OTG HID kb/mouse on USB-c cable to iPad/iPhone/Pixel, like a remote KVM.

Once KB/mouse emulation exists, it can be integrated with Linux window manager to treat a tablet/phone as external "display", e.g. move Linux mouse pointer to the right edge of laptop display, push to the right with a bit of physics delay, then activate kb/mouse emulation and send all keystrokes and mouse movements over USB-c cable to the external device.

This would avoid the travel weight cost of a dedicated keyboard for tablet or phone.

platevoltage
6d ago
This was a good read. I'm currently working on interfacing a microcontroller with USB racing wheels. Parsing the incoming HID data is easy, sending force feedback commands back to the wheel is a different story. A lot of USB sniffing had to be done given Logitech and MOZA's lack of documentation.

Anyways, I'm learning as I go and this writeup was informative.

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ID: 45910244Type: storyLast synced: 11/16/2025, 9:42:57 PM

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