Cat Flap

Hmm - well the values are 16 bit signed, so -32768..32767. I guess it's possible that it went overrange and rather than clipping, the accelerometer rolls over?

Maybe you could try this... It sets the accelerometer range to 4g (what is was before, not 2g)

on = function(options) {
  options = options||{};
  // motion
  Puck.accelOn();
  Puck.accelWr(0x15,0x10);  // CTRL6-C - XL_HM_MODE=1, low power
  Puck.accelWr(0x0D,0x00); // INT1_CTRL - disable
  Puck.accelWr(0x11,0); // CTRL2_G power down gyro
  Puck.accelWr(0x10,0x18);  // CTRL1_XL accelerometer 12.5hz, 4g
  Puck.accelWr(0x58,0x90); // TAP_CFG - enable irq, add filter
  Puck.accelWr(0x5C,options.duration||0x02); // WAKE_UP_DUR - very low duration
  Puck.accelWr(0x5B,options.threshold||0x02); // WAKE_UP_THS - low threshold
  Puck.accelWr(0x5E,0x20);  // MD1_CFG wakeup on INT1
}

But maybe if that helps it should actually be higher? 8 or 16 g?