Homepage of P. Christopher Staecker: The MK Area Calculator

The MK Area Calculator is an electronic gadget from the 1950s which calculates the area of any region drawn on paper.

About

Here is a short video about the MK Area Calculator:

Original instructions & other stuff

These files were generously provided by Bob Martin, grandson of Roy Kuykendall and son of Warren Martin. Thanks very much to Bob for his permission to repost them.

MK Area Calculator instructions

Magazine ads

Magazine ad for the unreleased Spy-N-Shoot

Make your own (arduino-based)

My version in the video is made with an arduino in a 3D-printed case. The materials for this cost me about $60, not including the 3D-printing.

Shopping list (Amazon links for convenience- you may be able to find better stuff elsewhere, and I don't get a cut):

• Conductive copper tape (3mm wide) for the grid overlay
• Test leads set including the red/black wires
• Set of banana connector jacks, where the red/black wires plug in to the box
• 4-Digit LED display TM1637 (you will need to remove the wires- connect on the back rather than the front)
• Arduino Uno R3 with basic components: some jumper wires, a 10K ohm resistor, simple pushbutton
• Basic soldering supplies

If you don't plan on making the 3D-printed case, you could use a breadboard without soldering, and you won't need the banana connector jacks.

Downloads:

• 3D-printable case (bottom) STL
• 3D-printable case (top) STL
• Plain 3D-printable case (bottom) STL (without "PCS" or "Printed by Vincent")
• Arduino code file including wiring instructions
• Grid overlay PDF (letter size) Lay copper strips on the black lines

I am releasing all these designs into the public domain: anyone has my permission to do whatever you want with them without attribution. But if you really do build one, I'd love to hear about it!

Make your own (from scratch)

If you are good with building electronics by hand, you can probably recreate the original design from this detailed circuit diagram included by the manufacturer. I've never tried this.

• Original circuit diagram

Other stuff

• Other pages about antique calculating devices