Raw HID support for ZMK

This ZMK module enables Raw HID functionality for ZMK.

Features

It allows bidirectional communication between host computer and keyboard over HID interface. Both USB and BT connections are supported.

Example usage - display widget with HID support, which can accept data from computer using companion app and display current time/layout/volume.

Installation

Warning

Enabling this module alone does not bring any functionality by default. You need another module or custom code to consume events, and companion app to send them.

To use, first add this module to your config/west.yml by adding a new entry to remotes and projects:

manifest:
  remotes:
    - name: zmkfirmware
      url-base: https://github.com/zmkfirmware
    - name: zzeneg # <-- new entry
      url-base: https://github.com/zzeneg
  projects:
    - name: zmk
      remote: zmkfirmware
      revision: main
      import: app/west.yml
    - name: zmk-raw-hid # <-- new entry
      remote: zzeneg
      revision: main
  self:
    path: config

For more information, including instructions for building locally, check out the ZMK docs on building with modules.

Add the raw_hid_adapter as an additional shield to your build, e.g. in build.yaml:

---
include:
  - board: nice_nano_v2
    shield: molekula raw_hid_adapter

Adding support in other modules

Subscribe to raw_hid_received_event and implement your own listener:

static int raw_hid_received_event_listener(const zmk_event_t *eh) {
    struct raw_hid_received_event *event = as_raw_hid_received_event(eh);
    if (event) {
        // do something
    }

    return ZMK_EV_EVENT_BUBBLE;
}

ZMK_LISTENER(process_raw_hid_event, raw_hid_received_event_listener);
ZMK_SUBSCRIPTION(process_raw_hid_event, raw_hid_received_event);

Configuration

Name	Description	Default
CONFIG_RAW_HID	Enable Raw HID module	n
CONFIG_RAW_HID_USAGE_PAGE	HID Usage Page	0xFF60
CONFIG_RAW_HID_USAGE	HID Usage	0x61
CONFIG_RAW_HID_REPORT_SIZE	HID Report size (number of bytes)	32
CONFIG_RAW_HID_DEVICE	New HID device name	HID_1

Thanks

This module is heavily based on badjeff's zmk-hid-io.