Step by step guide to do a custom USB HID device on STM32 using ST CubeMX. There is already one page addressing it but without any details for beginners.
I will use my custom board based on STM32L0, but any Nucleo can be used by wiring a USB cable to 5V, GND, USB_D+, USB_D-.

For a project, I need media keys (play, volume, mute, …) and a way to lock a computer under Windows (Windows+L keys). There is a lot of HID keyboard descriptors on the Internet, some are for keyboards + media but all contain at least one unused byte… Not a good thing for embedded systems with constraint memory. Why? The descriptor can be found in USB-IF example (Appendix B) and describe a boot compatible keyboard. So unless you need your keyboard in boot menus, this byte can be dropped. Also, the example defines 6 simultaneous keys, I decreased it to three as I don’t need more.

After the STM32L151, I am now designing a board for STM32L052. Following are some notes about ST application notes I read to design an board.

What can you do on a rainy evening when you go to your hackerspace?
Take a NoteRF V2 PCB, a GPS, a battery, and you can make a LoRaWAN GPS tracker!