Projects

A collection of apps, side projects, and things I’ve built over the past 20 years – from software tools and IoT hacks to custom PCBs and woodworking builds.

Software & Apps #

DaysAbroad (2026) – iOS app that uses GPS to automatically track how many days you spend in each country. Built for tax residency rules, Schengen limits, and digital nomads who lose count. zebralabs.org/days-abroad

Brasil Papaya App (2026) – Native iOS (Swift) and Android (Kotlin) music toolkit for the band’s 30th anniversary. Guitar & bass tuner, metronome, sound meter, and waveform visualizer. App Store / Google Play

VitalTrends (2026) – Unified health dashboard pulling WHOOP and Withings data into 12+ interactive charts with auto-syncing, CSV exports, and public profiles. vitaltrends.net

Markdown to EPUB Converter (2026) – Paste markdown or drop a URL, get a clean EPUB. Built for reading saved articles on my tiny eINK reader. md2epub.danielandrade.net

pwdquery (2018) – Password breach checker built on a 90GB+ database of leaked credentials. Scrapers, scripts, and the whole pipeline automated from scratch.

Hardware & Electronics #

DIY Helium Hotspot (2020) – Raspberry Pi + LoRa gateway turned into a working Helium blockchain hotspot during the alpha program.

Overnight Sensation Speakers (2020) – Audiophile-grade DIY speakers with CNC-cut pine-wood cabinets, 3D-printed crossover boards, and hand-soldered RLC filters.

Automated Door System (2018) – IoT door opener with Particle Photon and relay. The old Lisbon apartment door was a nightmare – now it opens from a phone.

Metronome v2.0 (2016) – Started as a breadboard project in 2007 and evolved into a proper PCB learn-to-solder kit with 555 timer IC.

3.5mm Audio Switch (2016) – Tiny PCB with a 3PDT switch to toggle audio between a Raspberry Pi and a Mac. Born from cable-swapping annoyance in Berlin.

AD5204 Breakout Board (2014) – Custom PCB breakout for the AD5204 4-channel digital potentiometer. Eagle CAD, OSH Park, shared openly.

Line Follower Robot (2014) – Old school analog robotics – no microcontroller, just LM358 OpAmps, LDRs, and transistors.

Arduino Breathalyzer (2010) – MQ-3 alcohol gas sensor + Arduino + 10 LEDs = the hit of an electronics meetup party in Florianopolis.

Binary Clock (2008) – 13 LEDs, an Arduino, and a movie night that turned into a build session. Displays time in binary because why not.

Home Builds #

HTPC 2.0 (2011) – Second-gen home theater PC with AMD E-350 Zacate on Mini-ITX. Big upgrade from the original Core 2 Duo build (2008).

DIY NAS Server (2011) – Fanless Mini-ITX NAS running Ubuntu on Intel Atom D510MO. Custom acrylic case, Samba, SSH, Transmission – all under $200.