Arduino micro as (raw) HID device

Projects General Guidance
1

Hi Everyone!

I just got my Arduino Micro, I played a bit with the USB options. Made it into a usb keyboard :slight_smile: and I saw there is also a mouse class to make it into a mouse. But how about setting it up as a gamepad or even a raw hid device? How can I make it into other usb devices? Can I just write a library or are the mouse and keyboard built into the boatloader?

If the mouse and keyboard code are in the boatloader, can I just download the code for it change it and recompile?

By the way, I have knowledge of c/c++ and some basic assembly knowledge. So I don't mind writing some code.

2

They are not in the bootloader. The bootloader loads your new code.

The HID stuff is in the loaded code.

Find the file HID.cpp and look inside that.

3

Thanks, yeah I just noticed the HID.cpp file.

4

As I understand it in theory it is possible but there are a few snags and no one has done it yet.

5

Yeah it is possible, I had to make some changes to the HID.cpp file. Now the Arduino can be a gamepad too. XD

I got a working joystick and some buttons. Now I am looking if I can somehow add analog triggers. But I am not sure if those are supported on a generic hid gamepad. I can't seem to get the pc to recognize them.

6

Hi

It's been a while since anything had been posted in this topic but if you didn't figure it out already, i have it working on my Leonardo.
My hid descriptor for my gamepad/joystick (hid.cpp)

    0x05, 0x01,                    // USAGE_PAGE (Generic Desktop)
    0x09, 0x04,                    // USAGE (Joystick)
    0xa1, 0x01,                    // COLLECTION (Application)
		0x85, 0x01,                    //     REPORT_ID (1) // change to 3 if using mouse and keyboard on 1&2
		0xa1, 0x00,                    //   COLLECTION (Physical)
			
			0x05, 0x09,                    //     USAGE_PAGE (Button)
			0x19, 0x01,                    //     USAGE_MINIMUM (Button 1)
			0x29, 0x10,                    //     USAGE_MAXIMUM (Button 16)
			0x15, 0x00,                    //     LOGICAL_MINIMUM (0)
			0x25, 0x01,                    //     LOGICAL_MAXIMUM (1)
			0x95, 0x10,                    //     REPORT_COUNT (16)
			0x75, 0x01,                    //     REPORT_SIZE (1)
			0x81, 0x02,                    //     INPUT (Data,Var,Abs)

			0x05, 0x01,                    // USAGE_PAGE (Generic Desktop)
			0x09, 0x01,                    // USAGE (piointer)
			0xa1, 0x00,                    //   COLLECTION (Physical)	
				0x09, 0x30,                    //     USAGE (X)
				0x09, 0x31,                    //     USAGE (Y)
				0x09, 0x32,                    //     USAGE (Z)
				0x09, 0x33,                    //     USAGE (Rx)
				0x09, 0x34,                    //     USAGE (Ry)
				0x09, 0x35,                    //     USAGE (Rz)
				0x15, 0x81,                    //     LOGICAL_MINIMUM (-127)
				0x25, 0x7f,                    //     LOGICAL_MAXIMUM (127)
				0x95, 0x06,                    //     REPORT_COUNT (6)
				0x75, 0x08,                    //     REPORT_SIZE (8)
				0x81, 0x02,                    //     INPUT (Data,Var,Abs)
			0xc0,                          //   END_COLLECTION

			0x05, 0x01,                     // Usage Page (Generic Desktop)
			0x09, 0x39,                     // Usage (Hat switch)
			0x15, 0x00,                     // Logical Minimum (0)
			0x25, 0x07,                     // Logical Maximum (7)
			0x35, 0x00,                     // Physical Minimum (0)
			0x46, 0x3B, 0x01,               // Physical Maximum (315)
			0x75, 0x04,                     // Report Size (4)
			0x95, 0x01,                     // Report Count (1
			0x65, 0x14,                     // Unit (20)
			0x81, 0x42,                     // Input (variable,absolute,null_state)
				// 4bits of padding
			0x95, 0x04,                    //     REPORT_COUNT (4)
			0x75, 0x01,                    //     REPORT_SIZE (1)
			0x81, 0x01,                    //     INPUT (Data,Var,Abs)
			
		0xc0,                          //   END_COLLECTION
    0xc0,                           // END_COLLECTION

16 buttons, 6 axis (8bit but can be changed easily ), 1hat(d-pad)

and the corresponding structure (in USBAPI.h):

typedef struct {
	union 
	{
		struct {
			bool	b0: 1 ;
			bool	b1: 1 ;
			bool	b2: 1 ;
			bool	b3: 1 ;
			bool	b4: 1 ;
			bool	b5: 1 ;
			bool	b6: 1 ;
			bool	b7: 1 ; 
			bool	b8: 1 ;
			bool	b9: 1 ;
			bool	b10: 1 ;
			bool	b11: 1 ;
			bool	b12: 1 ;
			bool	b13: 1 ;
			bool	b14: 1 ;
			bool	b15: 1 ; 
		} ;
		uint16_t buttons;
	};
	int8_t X	;
	int8_t Y	;
	int8_t Z	;
	int8_t Rx	;
	int8_t Ry	;
	int8_t Rz	;
	
	int8_t	hat: 4 ;  // -1 = neutral position
	int8_t	: 4 ;	  //padding  
	
} GamepadReport;

no we can send the data

GamepadReport _GamepadReport;
_GamepadReport.hat=-1; // default nullstate
_GamepadReport.X=random(-127,127);// just a test
_GamepadReport.buttons=random(0,0xff);// just a test random on first 8 bits(buttons)
_GamepadReport.b9=1;// just
// or do whatever
// and send
HID_SendReport(1,&_GamepadReport ,sizeof(GamepadReport )); //1 coresponds to report id in HID.cpp

or write a simple class

USBAPI.h

class Gamepad_
{
private:
	uint8_t rapid;
public:
	GamepadReport _GamepadReport;
	Gamepad_(void);
	void begin(uint8_t id);
	void end(void);
	void send();
};
extern Gamepad_ Gamepad;

HID.cpp:
Gamepad_::Gamepad_(void){		rapid=3;              }
void Gamepad_::begin(uint8_t sid){	rapid=sid;  }
void Gamepad_::end(void){}
void Gamepad_::send(){
	HID_SendReport(rapid,&_GamepadReport,sizeof(GamepadReport));
}

and in you sketch:

before setup():
  Gamepad_ Gamepad;

in setup():
  Gamepad.begin(1);//report_id of your HID 

and in loop():
  Gamepad._GamepadReport.X=random(-127,127);// just a test
  //bunch of IF statements
  Gamepad.send();

i also was experimenting with dual/triple gamepads or with 4 hats more axis 128 buttons ,
windows can show up to 32 buttons;
hats are all drawn into same space with different colors arrows;
and it can get confused with more than 6 axis with showing/ not showing few.

i hope this will help someone.

PS this is my 1st post here, cool to be part of the Community.