Mechanical Calculator (Addition & Multiplication!)

🧮 I designed a 3D-printable mechanical calculator that can perform ➕ addition and ✖ multiplication!

Available in 2 Styles:

How to Use It

Move the feet to the numbers you want to add/multiply and the hands will point to the answer!
There are 2 bases available to print: ✖ Multiplication and ➕ Addition.

How it works

📐 This mechanical calculator operates using a planar hinge mechanism involving symmetrical isosceles right-angled triangles. The hypotenuses of these triangles slide along number lines, while their vertices are connected, forming a hinged rhombus. By placing the sliding points on different integers, the calculator determines the midpoint of these integers to display the results. This model is based on the expired “educated monkey” patent from 1915.

Assembly Guide

Froggy Version:

Step 1: Place the Screws, Feet, and Vertical Bar onto the Base.

Step 2: Add the Legs. The Left Leg must go on top of the Right Leg as pictured.

Step 3: Add the Right Hand. (Note: The Right Hand is thicker than the Left Hand)

Step 4: Add the Left Hand.

Step 5: Add the Face.

Step 6: Add the Nuts. You may need to tighten/loosen them for smooth operation.

Step 7: You're done!

Basic Version:

Step 1: Place the Screws, Feet, and Vertical Bar onto the Base.

Step 2: Add the Legs. The Left Leg must go on top of the Right Leg as pictured.

Step 3: Add the Right Hand. (Note: The Right Hand is thicker than the Left Hand)

Step 4: Add the Left Hand then add the Nuts. You may need to tighten/loosen them for smooth operation.