• Initial observations

    shaun.dougherty07/19/2015 at 09:43 0 comments

    I acquired an old split-flap display that was on sale at Narita Airport as part of a summer sale to get rid of old airplane parts/airport related items.

    *My electronics knowledge is pretty elementary, so I may not be using the correct terminology when identifying the parts. Any corrections or thoughts about how the display works would be welcome.

    The main part of the hardware seems to be an old type of stepper motor. There is a six pin connector. Two of the pins are bridged with a ceramic capacitor and run what I am guessing is some sort of coil. The other four pins run to a small circuit board. The board is populated with two sensors and a diode.

    The ceramic capacitor is about 14mm in size and is branded

    H J2
    68Z10
    The writing on the diode looks like "14N".

    Spinning the motor by hand, the arm moves every 10 turns. It takes 60 turns for one complete revolution of the arm. The flaps start when the arm is directly over the sensor on the circuit board.
    Googling the branding on the sensor (UGN 3119U 244) seemed to indicate that it is a Hall effect sensor. Unscrewing the circuit board, revealed another sensor positioned facing the inner wheel of the motor.

    I came across a data sheet for a Hall effect sensor with the same part number. I am not sure it is for the same part, but I the pin out diagram makes sense logically with what I see.

    From that, I believe the gray wire (gr) is ground. The white wire (bi) is the supply for the first sensor. The green wire (ve) is the supply for the second sensor. And the yellow wire (gi) is connected to the output of both sensors.

    This is a crude, probably not entirely accurate, drawing of the circuit components. The wire labels are directly from the circuit board. I do not know what they stand for.