About

Rondo started with a pretty common problem: I needed a way to remotely unlock doors, and every “smart” solution on the market either cost a fortune, required a proprietary hub, or meant running new wiring through walls I didn’t want to tear open.

Most commercial access control systems are built for enterprises — and priced accordingly. The affordable consumer options tend to lock you into a specific ecosystem, require a cloud subscription, or just don’t offer the flexibility to integrate with an existing API. None of that was going to work.

The alternative — running proper access control cabling — wasn’t much better. That means conduit, cable pulls, and either hiring someone or spending a weekend inside walls. For a setup that just needs to trigger a door release, that felt like massive overkill.

The actual solution

A Raspberry Pi, a button, and a few jumper wires turned out to be all that was needed. The Pi sits near the door, listens for a button press, and fires a POST request to an API that handles the unlock. No proprietary hub, no subscription, no new cabling — just a small device plugged into power and connected to the network.

The button is wired directly to the Pi’s GPIO pins. The whole thing runs in a Docker container, deployed and managed with Ansible so it’s easy to push updates or roll out to new devices without touching each one individually.

Why Ansible?

Once it became clear that this could scale to multiple doors, managing each Pi by hand stopped being realistic. Ansible lets me treat every Pi the same way — one playbook run pushes the latest config and restarts the container across the whole fleet. Semaphore puts a UI on top of that so it doesn’t require a terminal every time.

The name

Rondo is a musical form where a main theme keeps returning throughout a piece — it repeats. Felt fitting for something that sits in a loop, waiting to do the same thing over and over.