Experimental text input method on Pixl.js/Chording-ish Bluetooth keyboard

The modifications to the above to get it to work with MPR121 - put the following into onInit()

SCL=D15;
SDA=D14;
IRQ=D16;

I2C1.setup({scl:SCL,sda:SDA});

sensor = require("MPR121").connect(I2C1, function() {});

// Function to be called when MPR121 notifies us of change
setWatch(function(e) {
    var value = sensor.touched() & 0x0f; // Filter out other inputs
    if (value==0) { // All buttons up: Emit the key
      emitkey(state);
      state='_';
    }
// Buttons map to MP121 inputs 0,1,2,3 -> bits 1,2,4,8
    if (value==1) keydown(0);
    if (value==2) keydown(1);
    if (value==4) keydown(2);
    if (value==8) keydown(3);

}, IRQ, {edge: 'falling', repeat: true});