The DigiRule

Posted on Friday, October 9th, 2015 in tools by DP

The DigiRule

Brad has designed a cool binary PCB ruler, The DigiRule:

So I made the DigiRule! – The DigiRule is a 15cm (6″) ruler with which is marked in binary digits rather than decimal. It has a number of built in digital functions including:

  • Logic Gates
    -NOT Gate (Inverter)
    -OR Gate
    -AND Gate
    -XOR Gate
    -NOR Gate
    -NAND Gate
    -XNOR Gate
  • Flip Flops
    -SR Flip Flop
    -JK Flip Flop
    -Toggle Flip Flop
    -Data Flip Flop
  • Four bit binary up/down counter

It is powered by a single 3V CR1220 button battery and the brains of the unit is a PIC 18F43K20 microcontroller (which is a greatly over powered device for such a simple task – but they are cheap!) The functions listed above are controlled by nine surface mount push buttons and has twenty three surface mount LED’s to show the status of the inputs and outputs.

Project info at Brads project site.

Check out the video after the break.

This entry was posted on Friday, October 9th, 2015 at 4:00 pm and is filed under tools. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

8 Responses to “The DigiRule”

  1. rumburack says:

    There is no help at all that tells me how to turn it on and to press the buttons. Call me overcautious, but for someone who doesn’t know how AND works, it might be very helpful…

    • KH says:

      Typical power-down current for this PIC18F43K20 range is 0.1uA typical 25degC Vdd 3V. Don’t need a power button.

      • Alan says:

        With current that low, maybe the next version will have solar cells and a [re]charging circuit.

      • KH says:

        A bit difficult, unless you use LCD. Amorphous silicon cells on a calculator I would guess is in the range of 5 to 50uA indoors. Probably enough for the MCU running the low speed RC oscillator, but not much else, and your display options will be severely limited. Charging would be tough to do, and a coin-packaged supercap is still pretty fat…

  2. David says:

    Brad – that is SO cool mate! – well done :)

  3. Crawford says:


    You got some additional ink on this from Max Maxfield over at EETimes:

  4. Manuel says:

    shut up and take my money !

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