Wiring up to the AN2131


Posted on Feb 5, 2014

It`s just a AN2131 chip with the required support circuitry - crystal oscillator, power regulators etc. First I took the inputs and outputs of the key matrix and wired them to the GPIO ports of the AN2131. This was just a matter of plugging the whole lot into some protoboard. This didn`t work too well, as the keys would get `stuck` often. This is because an unconnected chip leg can `float` between


Wiring up to the AN2131
Click here to download the full size of the above Circuit.

on and off due to the residual charge held in the wire. The solution is to add pull-down resistors which allow this residual charge to flow to ground when the key is released. I added one to each input of the circuit. I used a variety of spare resistors from the junk box 320 ohms to 1000 ohms. This is the final circuit diagram:




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Multi-spark for Electronic Ignition
    Static charge-electricity detector
    Sequential timing
    1000:1 Tuning Voltage-Controlled Filter
    2 X 20 W car amplifier circuit with TDA2009 Schematic Diagram
    Rock Paper Scissors Playing Glove
    Cellphone Charger Using Bike Battery
    Multicolor HD LED
    Analog PWM connection with FIG zps-101 interface
    XTR108 voltage excitation bridge circuit diagram
    Half-wave rectifier circuit principle



    Top