Open-source & free

Cool projects you can actually build tonight

Real projects. Real hardware. Real fun. OpenGizmo is where small hardware ideas get documented, with open-source builds and the details you wish you'd found before starting.

What's in here

Practical ESP32 builds, plus the notes that explain what they do and how they work.

Purpose-built gadgets

Open-source ESP32 builds with clear jobs, real hardware, and enough context to understand how the whole device comes together.

How they actually work

The useful bits: setup flow, device behavior, hardware choices, firmware details, and the interactions that make each build usable.

Context, not fluff

Project pages cover the builds, and the blog explains the reasoning, tradeoffs, and maker context around them.

OpenGizmo Projects

Browse the current OpenGizmo builds and jump into the project pages for hardware details, setup flow, and what each gadget is actually for.

Open-source ESP32 + MAX7219 project

Gizmo Ticker

A WiFi-connected crypto display built with an ESP32, a MAX7219 LED matrix, and a Nuxt 4 web app for browser-based setup and configuration.

Open-source ESP32 + Reolink project

Gizmo Reolink Switch

An ESP32-powered quiet-exit switch that uses a button, buzzer, 16x2 I2C LCD, and WiFi connection to temporarily mute Reolink NVR notifications and recording.

OpenGizmo has a blog too

There are notes, experiments, and build write-ups in there too, good if you want the story behind the hardware.