Get official MakeyMakey software from github. MakeyMakey tutorial

Make arduino behave like a keyboard

Program the usb-chip

Upload *.hex file to the serial communicator chip. The hex-files can be found here.

avrdude -c avrispmkII -P usb -p usb162 -u -U flash:w:/path/to/hex -F

eg. act like normal arduino $ sudo avrdude -c avrispmkII -P usb -p usb162 -u -U flash:w:Arduino-usbserial-uno.hex -F

act like keyboard $ sudo avrdude -c avrispmkII -P usb -p usb162 -u -U flash:w:Arduino-keyboard-0.3.hex -F

Follow the changes $ tail -f /var/log/kern.log

Remember the Arduino need!!! to be powered while re-flashing. Eg. either connect the usb-stick or a external power connector. Otherwise we’ll get an error: $ avrdude: initialization failed, rc=-1

The cable from AVRISP MKII(flashing devise) have to go into the board for the usb-chip and out of the board for the atmega chip.

Key-codes

The keys are sent using Serial.write. The key codes is found from HID usage table p. 53.

Small example sending ‘keyboard volume up’ key.

uint8_t buf[8] = { 0 };
buf[2] = 128; // volume up
Serial.write(128,8) // send key press
buf[2] = 0;
Serial.write(buf, 8); // Release key

Larger example

// Arduino USB Keyboard HID demo
//
// Sends Volume up, hello world, and Volume Down to the host PC
//
// From http://hunt.net.nz/users/darran/weblog/b3029/Arduino_UNO_Keyboard_HID_version_03.html

uint8_t buf[8] = { 0 }; /* Keyboard report buffer */

void setup();
void loop();

#define KEY_LEFT_CTRL   0x01
#define KEY_LEFT_SHIFT  0x02
#define KEY_RIGHT_CTRL  0x10
#define KEY_RIGHT_SHIFT 0x20

void setup()
{
    Serial.begin(9600);
    delay(200);
}

char *str = "+hello world-";

void loop()
{
    char *chp = str;
    delay(5000);
    while (*chp) {

    if ((*chp >= 'a') && (*chp <= 'z')) {
        buf[2] = *chp - 'a' + 4;
    } else if ((*chp >= 'A') && (*chp <= 'Z')) {
        buf[0] = KEY_LEFT_SHIFT;    /* Caps */
        buf[2] = *chp - 'A' + 4;
    } else {
        switch (*chp) {
        case ' ':
            buf[2] = 0x2c;  // Space
        break;
        case '+':
           buf[2] = 128;    // Volume up
           break;
        case '-':
           buf[2] = 129;    // Volume down
           break;
        default:
            /* Character not handled. To do: add rest of chars from HUT1_11.pdf */
        buf[2] = 0x37;  // Period
        break;
        }
    }

    Serial.write(buf, 8);   // Send keypress
    buf[0] = 0;
    buf[2] = 0;
    Serial.write(buf, 8);   // Release key
    chp++;
    }
}

Apps to use

Virtual keyboard

pawsen / MakeyMakey