What is the best way to make your own media keys with unique keyboard functionality?

Question

Do it yourself

The idea is to create unique media keys on the keyboard for:

1. entering certain shortcuts, for example, replace Shift + Ctrl + S with one key
   
2. entering certain characters, such as emoji emoticons
   
3. entering specific words with a single keystroke
   
4. the solution should be universal, that is, another not very smart person who received such a keyboard could ideally use it simply by connecting and installing drivers
   

My implementation plan:

1. reflash the keyboard controller so that it responds to pressing certain keys with non-standard idle scancodes (this way the buttons will not work until the drivers are installed, which is good)
   
2. write a filter driver for Windows that will convert these non-standard scan codes into the desired functionality (input of shortcuts, symbols, words)
   

With this plan, I have a couple of questions:

1. Did I draw up the implementation plan correctly? Are there other options for implementing this idea?
   
2. What are the pitfalls in my plan? If so, in which direction to dig?
   

Answer 1

AHK - I use it myself: the mouse wheel as the volume when you hover over the taskbar, the middle button is off / on. sound along with the microphone. Really convenient!
https://www.autohotkey.com/

Answer 2

myasnick.com/soft/typeiteasy
https://www.autohotkey.com/

Answer 3

The idea is clear, but it will be very difficult to implement.
1. Flashing the original keyboard controller will not work. You will have to sculpt a new board with your firmware.
2. If you want the keys to issue fixed combinations, this is one thing, if there is another interface on the PC, this is another.
3. Once I myself thought to use idle codes for implementation, the idea is not the best. It's easier to just send data via usb and emulate anything with your software.
4. Use USB HID and you won't need drivers at all)