qmk-firmware/docs/feature_mouse_keys.md

Mouse keys

Mouse keys is a feature that allows you to emulate a mouse using your keyboard. You can move the pointer at different speeds, press 5 buttons and scroll in 8 directions.

Adding mouse keys to your keyboard

To use mouse keys, you must at least enable mouse keys support and map mouse actions to keys on your keyboard.

Enabling mouse keys

To enable mouse keys, add the following line to your keymap’s rules.mk:

MOUSEKEY_ENABLE = yes

Mapping mouse actions

In your keymap you can use the following keycodes to map key presses to mouse actions:

Key	Aliases	Description
KC_MS_UP	KC_MS_U	Move cursor up
KC_MS_DOWN	KC_MS_D	Move cursor down
KC_MS_LEFT	KC_MS_L	Move cursor left
KC_MS_RIGHT	KC_MS_R	Move cursor right
KC_MS_BTN1	KC_BTN1	Press button 1
KC_MS_BTN2	KC_BTN2	Press button 2
KC_MS_BTN3	KC_BTN3	Press button 3
KC_MS_BTN4	KC_BTN4	Press button 4
KC_MS_BTN5	KC_BTN5	Press button 5
KC_MS_WH_UP	KC_WH_U	Move wheel up
KC_MS_WH_DOWN	KC_WH_D	Move wheel down
KC_MS_WH_LEFT	KC_WH_L	Move wheel left
KC_MS_WH_RIGHT	KC_WH_R	Move wheel right
KC_MS_ACCEL0	KC_ACL0	Set speed to 0
KC_MS_ACCEL1	KC_ACL1	Set speed to 1
KC_MS_ACCEL2	KC_ACL2	Set speed to 2

Configuring mouse keys

Mouse keys supports two different modes to move the cursor:

• Accelerated (default): Holding movement keys accelerates the cursor until it reaches its maximum speed.
• Constant: Holding movement keys moves the cursor at constant speeds.

The same principle applies to scrolling.

Configuration options that are times, intervals or delays are given in milliseconds. Scroll speed is given as multiples of the default scroll step. For example, a scroll speed of 8 means that each scroll action covers 8 times the length of the default scroll step as defined by your operating system or application.

Accelerated mode

This is the default mode. You can adjust the cursor and scrolling acceleration using the following settings in your keymap’s config.h file:

Define	Default	Description
MOUSEKEY_DELAY	300	Delay between pressing a movement key and cursor movement
MOUSEKEY_INTERVAL	50	Time between cursor movements
MOUSEKEY_MAX_SPEED	10	Maximum cursor speed at which acceleration stops
MOUSEKEY_TIME_TO_MAX	20	Time until maximum cursor speed is reached
MOUSEKEY_WHEEL_MAX_SPEED	8	Maximum number of scroll steps per scroll action
MOUSEKEY_WHEEL_TIME_TO_MAX	40	Time until maximum scroll speed is reached

Tips:

• Setting MOUSEKEY_DELAY too low makes the cursor unresponsive. Setting it too high makes small movements difficult.
• For smoother cursor movements, lower the value of MOUSEKEY_INTERVAL. If the refresh rate of your display is 60Hz, you could set it to 16 (1/60). As this raises the cursor speed significantly, you may want to lower MOUSEKEY_MAX_SPEED.
• Setting MOUSEKEY_TIME_TO_MAX or MOUSEKEY_WHEEL_TIME_TO_MAX to 0 will disable acceleration for the cursor or scrolling respectively. This way you can make one of them constant while keeping the other accelerated, which is not possible in constant speed mode.

Cursor acceleration uses the same algorithm as the X Window System MouseKeysAccel feature. You can read more about it on Wikipedia.

Constant mode

In this mode you can define multiple different speeds for both the cursor and the mouse wheel. There is no acceleration. KC_ACL0, KC_ACL1 and KC_ACL2 change the cursor and scroll speed to their respective setting.

You can choose whether speed selection is momentary or tap-to-select:

• Momentary: The chosen speed is only active while you hold the respective key. When the key is raised, mouse keys returns to the unmodified speed.
• Tap-to-select: The chosen speed is activated when you press the respective key and remains active even after the key has been raised. The default speed is that of KC_ACL1. There is no unmodified speed.

The default speeds from slowest to fastest are as follows:

• Momentary: KC_ACL0 < KC_ACL1 < unmodified < KC_ACL2
• Tap-to-select: KC_ACL0 < KC_ACL1 < KC_ACL2

To use constant speed mode, you must at least define MK_3_SPEED in your keymap’s config.h file:

#define MK_3_SPEED

To enable momentary mode, also define MK_MOMENTARY_ACCEL:

#define MK_MOMENTARY_ACCEL

Use the following settings if you want to adjust cursor movement or scrolling:

Define	Default	Description
MK_3_SPEED	Not defined	Enable constant cursor speeds
MK_MOMENTARY_ACCEL	Not defined	Enable momentary speed selection
MK_C_OFFSET_UNMOD	16	Cursor offset per movement (unmodified)
MK_C_INTERVAL_UNMOD	16	Time between cursor movements (unmodified)
MK_C_OFFSET_0	1	Cursor offset per movement (KC_ACL0)
MK_C_INTERVAL_0	32	Time between cursor movements (KC_ACL0)
MK_C_OFFSET_1	4	Cursor offset per movement (KC_ACL1)
MK_C_INTERVAL_1	16	Time between cursor movements (KC_ACL1)
MK_C_OFFSET_2	32	Cursor offset per movement (KC_ACL2)
MK_C_INTERVAL_2	16	Time between cursor movements (KC_ACL2)
MK_W_OFFSET_UNMOD	1	Scroll steps per scroll action (unmodified)
MK_W_INTERVAL_UNMOD	40	Time between scroll steps (unmodified)
MK_W_OFFSET_0	1	Scroll steps per scroll action (KC_ACL0)
MK_W_INTERVAL_0	360	Time between scroll steps (KC_ACL0)
MK_W_OFFSET_1	1	Scroll steps per scroll action (KC_ACL1)
MK_W_INTERVAL_1	120	Time between scroll steps (KC_ACL1)
MK_W_OFFSET_2	1	Scroll steps per scroll action (KC_ACL2)
MK_W_INTERVAL_2	20	Time between scroll steps (KC_ACL2)