I'm a day 1 beginner to Arduino, and I am trying to obtain input from a USB keyboard. I've connected the USB keyboard to an Arduino USB host shield attached to an Arduino Uno r3, and I am using the example HID sketch (USBHIDBootKeyboard.ino) provided with the USB Host Shield libraries : https://github.com/felis/USB_Host_Shield_2.0/blob/master/examples/HID/USBHIDBootKbd/USBHIDBootKbd.ino
I am powering the Arduino Uno r3 + USB Host Shield via USB. Upon init, only Start is written to the Serial Monitor. Tests show that SetReportParser exits with 0. Yet the keyboards are silent. I've tried three keyboards, all of which work properly when connected to the computer.
When using USBHidBootMouse.ino with a mouse, movements & buttons are perceived and print messages as intended.
Also, it is recommended to use external power supply while working with HID devices – I’ve seen many devices which would refuse to function when Arduino receives power from its USB port only.
EDIT : I tried to test if the power was the issue, so I used a 5V generator with intensity measurement. The results are : the Arduino Uno r3 uses 60mA, the keyboard uses 60 mA, connecting to the serial port uses 40 mA (much to my surprise).
This means the keyboard's power requirements shouldn't be the problem.
Then what would the problem be ? I'm helpless here. If the library linked on the official Arduino site doesn't work, then it should mean i'm using it wrong.