Boxie – an always offline audio player for my 3 year old

Summary

Boxie - an always offline audio player for my 3 year old 2025-04-26 Channeling the spirit of the Gameboy Table of Contents At the end of July 2024, I embarked on a journey to learn electronics so I could build little gadgets for my son. In my introductory post I described a few electronic toys he uses frequently, including the Tonie Box, a device that plays audiobooks and has a huge library of content. The Tonie Box is great, until it isn't. As outlined in my original post, it has several deficiencies. Back then, I didn't think I would ever be able to build my own replacement. Fast forward a few months, and I've learned enough electronics to build my son's own audio player. Here's the preliminary result: It's been in "prod" since January 2025. It's his daily driver, be it at the breakfast table or when going for stroll in his buggy. Yes, the volume control is backwards. Easy to fix in software. What I learned these past months It turned out to be easier than I thought. I had to pick up these skills: Learn how to solder all kinds of components, including surface mounted components Abandon Arduino and embrace the ESP32 line of microcontrollers, which are a million times more versatile, powerful and cheaper. Learn how to read integrated circuit (IC) datasheets, and how to combine multiple ICs without things exploding Learn how to use Electronic Design Automation software like KiCad or in my case EasyEDA Pro, to create my own PCB designs Learn how to use CAD software to design enclosures I can print with my 3D printer. Coming from game development, I had previous exposure to 3D modelling software, which helps a lot. I ended up using Fusion 360 for this, which has a free tier. I also had to buy myself some tools. Here's my battle station. The list of all my tools (with purchase links): ERSA RDS80 soldering station. One of the higher-priced amateur soldering stations, but it's a workhorse. I use the 832KDLF 2.2mm chisel tip almost exclusively. Also get the dry cleaner met...