CustomHIDDevice.ino

#ifndef ARDUINO_USB_MODE
#error This ESP32 SoC has no Native USB interface
#elif ARDUINO_USB_MODE == 1
#warning This sketch should be used when USB is in OTG mode
void setup() {}
void loop() {}
#else
#include "USB.h"
#include "USBHID.h"
USBHID HID;

static const uint8_t report_descriptor[] = {
  // 8 axis
  0x05, 0x01,  // Usage Page (Generic Desktop Ctrls)
  0x09, 0x04,  // Usage (Joystick)
  0xa1, 0x01,  // Collection (Application)
  0xa1, 0x00,  //   Collection (Physical)
  0x05, 0x01,  //   Usage Page (Generic Desktop Ctrls)
  0x09, 0x30,  //     Usage (X)
  0x09, 0x31,  //     Usage (Y)
  0x09, 0x32,  //     Usage (Z)
  0x09, 0x33,  //     Usage (Rx)
  0x09, 0x34,  //     Usage (Ry)
  0x09, 0x35,  //     Usage (Rz)
  0x09, 0x36,  //     Usage (Slider)
  0x09, 0x36,  //     Usage (Slider)
  0x15, 0x81,  //     Logical Minimum (-127)
  0x25, 0x7f,  //     Logical Maximum (127)
  0x75, 0x08,  //     Report Size (8)
  0x95, 0x08,  //     Report Count (8)
  0x81, 0x02,  //     Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
  0xC0,        //   End Collection
  0xC0,        // End Collection
};

class CustomHIDDevice : public USBHIDDevice {
public:
  CustomHIDDevice(void) {
    static bool initialized = false;
    if (!initialized) {
      initialized = true;
      HID.addDevice(this, sizeof(report_descriptor));
    }
  }

  void begin(void) {
    HID.begin();
  }

  uint16_t _onGetDescriptor(uint8_t *buffer) {
    memcpy(buffer, report_descriptor, sizeof(report_descriptor));
    return sizeof(report_descriptor);
  }

  bool send(uint8_t *value) {
    return HID.SendReport(0, value, 8);
  }
};

CustomHIDDevice Device;

const int buttonPin = 0;
int previousButtonState = HIGH;
uint8_t axis[8];

void setup() {
  Serial.begin(115200);
  Serial.setDebugOutput(true);
  pinMode(buttonPin, INPUT_PULLUP);
  Device.begin();
  USB.begin();
}

void loop() {
  int buttonState = digitalRead(buttonPin);
  if (HID.ready() && buttonState != previousButtonState) {
    previousButtonState = buttonState;
    if (buttonState == LOW) {
      Serial.println("Button Pressed");
      axis[0] = random() & 0xFF;
      Device.send(axis);
    } else {
      Serial.println("Button Released");
    }
    delay(100);
  }
}
#endif /* ARDUINO_USB_MODE */