Show HN: Mathpad, a hardware keypad for typing math symbols (24 hours left)

After three years of development, my hardware project Mathpad is in its final 24 hours on Crowd Supply. I built this because I was tired of hunting for mathematical symbols every time I needed to type equations outside of specialized software.

What it is: A specialized USB-C keypad with 120+ mathematical symbols accessible via keypresses. Greek letters, calculus operators, set theory symbols, logic operators - everything you need for mathematical notation. Works anywhere you can type text.

Technical details: - QMK-based firmware (fully open source) - Unicode composition for universal compatibility - Multiple output modes (Unicode, LaTeX, Office equation codes) - Hot-swappable mechanical switches - Anodized aluminum case, custom UV-printed keycaps - Works on Windows, macOS, Linux

Why hardware vs software? Universal compatibility. Works in any text field - code editors, chat apps, documentation, even command lines. The development process was fascinating - from ugly $20 macropad prototype to custom PCB design to working with specialized keycap manufacturers. Weekly campaign updates document the entire journey if you're interested in the hardware development story.

Current status: 71 backers, final 24 hours remaining. All the hard engineering work is already done. This is just about getting enough orders to justify the production run.

Live demo video and complete technical documentation available on the campaign page. Would love feedback from the HN community on both the product and the development approach.