https://rndthts.dev/tags/side-project/ Recent content in Side-Project on rndthts.dev Hugo -- gohugo.io en-us Sun, 08 Mar 2026 12:30:00 +0100 https://rndthts.dev/posts/from-piggy-bank-to-cnc-matrix-generator/ Sun, 08 Mar 2026 12:30:00 +0100 https://rndthts.dev/posts/from-piggy-bank-to-cnc-matrix-generator/ <p>Most of what I write about here is software development. But in my free time, I also like to mess around with a CO2 laser CNC machine.</p> <p>Recently I wanted to build a piggy bank (saving box) where you track progress by crossing out a number grid until you hit a target amount.</p> <h2 id="the-problem-templates-exist-until-they-dont">The Problem: Templates Exist Until They Don&rsquo;t</h2> <p>Online templates work only for common totals. As soon as you need custom values, they break down:</p> <ul> <li>You want a custom target (for example: 750, 1350, 4200)</li> <li>You want your own grid size (rows and columns based on your physical design)</li> <li>You want specific denominations (for example: 1, 2, 5, 10, 20, 50, 100)</li> </ul> <p>As software engineers, we usually do not stop at &ldquo;close enough.&rdquo; We build what we actually need.</p> <h2 id="what-i-built-piggy-bank-matrix-builder">What I Built: Piggy Bank Matrix Builder</h2> <p><a href="https://rndthts.dev/tools/piggy-bank-matrix/"><strong>Piggy Bank Matrix Builder</strong></a> generates a CNC-ready SVG matrix using your target sum, chosen numbers, and grid size.</p> <h2 id="what-it-does">What It Does</h2> <ul> <li>Set a target sum</li> <li>Provide numbers (comma-separated) as denominations or any custom values</li> <li>Choose rows and columns</li> <li>Adjust a small-number bias to influence distribution</li> <li>Export as: <ul> <li>SVG (for laser/CNC)</li> <li>CSV (for further edits)</li> </ul> </li> </ul> <h2 id="why-this-was-a-good-fit-for-vibe-coding">Why This Was a Good Fit for Vibe Coding</h2> <p>This was a perfect vibe coding project for me:</p> <ul> <li>Performance is not a hard requirement</li> <li>The software is not safety-critical</li> <li>I do not usually write in this language stack</li> <li>I can verify results quickly by checking totals, previewing SVG, and testing on real material</li> </ul> <p>That makes AI-assisted iteration fast and practical, with clear validation at each step.</p> <h2 id="video-version">Video Version</h2> <p><a href="https://www.youtube.com/watch?v=h-mbZj34kWo"><strong>From Idea to Working Tool With Codex: Target Piggy Banks</strong></a></p> <h2 id="try-it">Try It</h2> <p>If you build something with it (different currencies, weird denominations, alternative layouts), I would love to see it.</p> <p>Tool: <a href="https://rndthts.dev/tools/piggy-bank-matrix/">https://rndthts.dev/tools/piggy-bank-matrix/</a></p>