Mystery Money Puzzle Kit

Authors: Lily Atton-Doornbos, Ben Boelens, Mitchel Krueger

Spring 2023

About our project: Mystery Money is a new project as of this semester with the open ended goal of creating some money for the enterprise. As a team we decided on the idea to sell digital logic based puzzle kits, with our main demographic being students, as we want there to be more opportunity for students to get hands on experience earlier on in their learning.


The kit consists of:
1 cardboard box with the Open Source Hardware logo on it
1 PCB board with IC holders, LEDs, and switches soldered on
2 74LS089 chips
2 74LS14N chips
2 7486AN chips
2 74LS32N chips
1 digital Puzzle book pdf
Access to PCB design files and kit customization CAD files

The goal of this project was to create a product that could be sold through the Open Source Hardware Enterprise. We aimed to develop a puzzle kit based on digital logic that would provide an open source and interactive learning experience for students interested in electrical and computer engineering (ECE). Our objectives were to create a puzzle kit with open access to all design files, which would guide users through various ECE topics in a fun and engaging way, and help them explore potential directions within the field of ECE.


To achieve our project goals, we decided to design a printed circuit board (PCB) with logic gate holders, switches, and LED’s, which would serve as the foundation of the puzzle kit. The PCB design was created using Eagle. The logic gate holders were designed to be compatible with commonly used digital logic gate ICs, allowing users to easily insert and swap out different logic gates to create different logic circuits.

In addition to the PCB design, we also developed a booklet that accompanied the puzzle kit, which can be found in the OSF repository linked in the appendix. The booklet provided information on the covered topics, including explanations of digital logic concepts, and included numerous puzzles that users could solve using the PCB functionality. The puzzles were designed to progressively increase in difficulty, providing a challenging learning experience for users at different skill levels. The booklet also encouraged users to personalize their puzzle kits by 3D printing their own customizations, creating their own puzzles, and sharing their creations with others.

One of the main goals we had with this kit was to make sure it was as affordable as possible while still having all the functionality we needed. We set a goal of having each box be sold for under $30.00. To achieve this we made a couple of decisions. First being to switch our original design of a 3d printed box to a cheaper cardboard box to house this kit. The next being to keep the puzzle booklet as an e-book rather than be printed. Through these decisions and our design, we were able to have the total cost of each kit, when buying materials for 100 kits, be $21.94. When factoring in fees and other costs, as well as a 15% profit margin. We would be able to make $6.04 in profit per box, while selling them for $29.99. The bill of materials showing a breakdown of these profits can be seen below.

Recreation Steps

A goal of the puzzle kit has been to make sure it is easily expandable and allows for individualization.

To recreate this kit, or expand upon it, the PCB design files and links to all parts used can be found in the OSF repository as well as some examples of 3D printable CAD files to add onto the box. These are all created in open source software. The PCB can be expanded to host more IC chips and Switches for more advanced puzzles.

Bill of Materials


Link to OSF: []