Milton Bradley Plus One National Semiconductor COP410L in 8-pin DIP Chip labeled ~/029 MM 57405 orientation sensor piezo COP410L DIP 8 pinout 1 ?? orientation sensor 2 GND ground 3 ?? orientation sensor 4 ?? orientation sensor 5 ?? orientation sensor 6 ?? transistor to piezo 3 CKI 100 pf cap to ground, 51K resistor to +5V 9 Vcc 5v positive The orientation sensor is a plastic cube with a BB inside. There are 5 pins around the BB perpendicular to the PCB, and 2 pins over the BB parallel to the PCB. 3 of the pins are grounded, and 4 connect to the COP410L. Home position: the power switch is facing down and towards you. Pin 3 is grounded. Rotate forward from the home position- pin 5 is grounded. Rotate left from the home position- pin 1 is grounded. Rotate right from the home position- pin 4 is grounded. I'm not sure exactly which of the 24 pins were bonded out in the 8-pin package. Obviously VCC, GND and CKI, as well as 4 inputs and one output. Looking at the die, 5 pads look as though bond wires had been attached: 9, 10, 13, 18 and 19. That corresponds to VCC, L3, L0, G1 and G2, a strange assortment. The code uses the opcodes INL, OBD, OMG, XAS and SKGBZ. So possibly L0, L3, G1 and G2 are used for the orientation sensor inputs and one of the D outputs or maybe SK for the piezo. Emulation of the code should help figure it out, although determining which of the orientation sensor inputs is which might be difficult.