qmk-firmware/docs/feature_auto_shift.md

Auto Shift: Why Do We Need a Shift Key?

Tap a key and you get its character. Tap a key, but hold it slightly longer and you get its shifted state. Voilà! No shift key needed!

Why Auto Shift?

Many people suffer from various forms of RSI. A common cause is stretching your fingers repetitively long distances. For us on the keyboard, the pinky does that all too often when reaching for the shift key. Auto Shift looks to alleviate that problem.

How Does It Work?

When you tap a key, it stays depressed for a short period of time before it is then released. This depressed time is a different length for everyone. Auto Shift defines a constant AUTO_SHIFT_TIMEOUT which is typically set to twice your normal pressed state time. When you press a key, a timer starts and then stops when you release the key. If the time depressed is greater than or equal to the AUTO_SHIFT_TIMEOUT, then a shifted version of the key is emitted. If the time is less than the AUTO_SHIFT_TIMEOUT time, then the normal state is emitted.

Are There Limitations to Auto Shift?

Yes, unfortunately.

1. Key repeat will cease to work. For example, before if you wanted 20 'a' characters, you could press and hold the 'a' key for a second or two. This no longer works with Auto Shift because it is timing your depressed time instead of emitting a depressed key state to your operating system.
2. Auto Shift is disabled for any key press that is accompanied by one or more modifiers. Thus, Ctrl+A that you hold for a really long time is not the same as Ctrl+Shift+A.
3. You will have characters that are shifted when you did not intend on shifting, and other characters you wanted shifted, but were not. This simply comes down to practice. As we get in a hurry, we think we have hit the key long enough for a shifted version, but we did not. On the other hand, we may think we are tapping the keys, but really we have held it for a little longer than anticipated.

How Do I Enable Auto Shift?

Add to your rules.mk in the keymap folder:

AUTO_SHIFT_ENABLE = yes

If no rules.mk exists, you can create one.

Then compile and install your new firmware with Auto Key enabled! That's it!

Configuring Auto Shift

If desired, there is some configuration that can be done to change the behavior of Auto Shift. This is done by setting various variables the config.h file located in your keymap folder. If no config.h file exists, you can create one.

A sample is

#ifndef CONFIG_USER_H
#define CONFIG_USER_H

#include "../../config.h"

#define AUTO_SHIFT_TIMEOUT 150
#define NO_AUTO_SHIFT_SPECIAL

#endif

AUTO_SHIFT_TIMEOUT (Value in ms)

This controls how long you have to hold a key before you get the shifted state. Obviously, this is different for everyone. For the common person, a setting of 135 to 150 works great. However, one should start with a value of at least 175, which is the default value. Then work down from there. The idea is to have the shortest time required to get the shifted state without having false positives.

Play with this value until things are perfect. Many find that all will work well at a given value, but one or two keys will still emit the shifted state on occasion. This is simply due to habit and holding some keys a little longer than others. Once you find this value, work on tapping your problem keys a little quicker than normal and you will be set.

{% hint style='info' %} Auto Shift has three special keys that can help you get this value right very quick. See "Auto Shift Setup" for more details! {% endhint %}

NO_AUTO_SHIFT_SPECIAL (simple define)

Do not Auto Shift special keys, which include -_, =+, [{, ]}, ;:, '", ,<, .>, and /?

NO_AUTO_SHIFT_NUMERIC (simple define)

Do not Auto Shift numeric keys, zero through nine.

NO_AUTO_SHIFT_ALPHA (simple define)

Do not Auto Shift alpha characters, which include A through Z.

Using Auto Shift Setup

This will enable you to define three keys temporarily to increase, decrease and report your AUTO_SHIFT_TIMEOUT.

Setup

Map three keys temporarily in your keymap:

Key Name	Description
KC_ASDN	Lower the Auto Shift timeout variable (down)
KC_ASUP	Raise the Auto Shift timeout variable (up)
KC_ASRP	Report your current Auto Shift timeout value
KC_ASON	Turns on the Auto Shift Function
KC_ASOFF	Turns off the Auto Shift Function
KC_ASTG	Toggles the statn of the Auto Shift feature

Compile and upload your new firmware.

Use

It is important to note that during these tests, you should be typing completely normal and with no intention of shifted keys.

1. Type multiple sentences of alphabetical letters.
2. Observe any upper case letters.
3. If there are none, press the key you have mapped to KC_ASDN to decrease time Auto Shift timeout value and go back to step 1.
4. If there are some upper case letters, decide if you need to work on tapping those keys with less down time, or if you need to increase the timeout.
5. If you decide to increase the timeout, press the key you have mapped to KC_ASUP and go back to step 1.
6. Once you are happy with your results, press the key you have mapped to KC_ASRP. The keyboard will type by itself the value of your AUTO_SHIFT_TIMEOUT.
7. Update AUTO_SHIFT_TIMEOUT in your config.h with the value reported.
8. Remove AUTO_SHIFT_SETUP from your config.h.
9. Remove the key bindings KC_ASDN, KC_ASUP and KC_ASRP.
10. Compile and upload your new firmware.

An Example Run

hello world. my name is john doe. i am a computer programmer playing with
keyboards right now.

[PRESS KC_ASDN quite a few times]

heLLo woRLd. mY nAMe is JOHn dOE. i AM A compUTeR proGRaMMER PlAYiNG witH
KEYboArDS RiGHT NOw.

[PRESS KC_ASUP a few times]

hello world. my name is john Doe. i am a computer programmer playing with
keyboarDs right now.

[PRESS KC_ASRP]

115

The keyboard typed 115 which represents your current AUTO_SHIFT_TIMEOUT value. You are now set! Practice on the D key a little bit that showed up in the testing and you'll be golden.