---
title: "Balkon Pi"
section: "smarthome"
tags: "smarthome"
parent: "/smarthome/"
description: "Balcony sensor, lighting, and audio automation running on a Raspberry Pi Zero W."
layout: base.njk
---
<h1>Balkon Pi</h1>
<div class="detail-content">

<p>A Raspberry Pi Zero W mounted near the balcony acts as a small,
self-contained smart-balcony controller: light control, an internet
radio player, sensor readings, and its own backup/monitoring, all on
very modest hardware. The goal is to make the balcony a more pleasant
space, light control when it gets dark, background music while sitting
outside, and temperature readings to know what to expect before stepping
out.</p>

<h2>What it does</h2>
<ul>
<li><strong>Audio output</strong> via a DIY PWM-to-analog circuit on two GPIO pins, the Pi Zero has no built-in audio jack, so this is a well-known community workaround using a small RC filter.</li>
<li><strong>Physical controls</strong>: a push button for the balcony light and a toggle switch for music playback, read directly via GPIO.</li>
<li><strong>HTTP communication</strong> with an ESP32-based balcony light controller.</li>
<li><strong>Internet radio</strong> via a lightweight command-line audio player, controlled by a small custom tool ported from an earlier bathroom-Pi project.</li>
</ul>

<h2>Hardware details</h2>
<p>The Pi Zero W is connected to an ESP32 microcontroller that handles
the actual light switching via a relay module. Communication happens
over HTTP, the Pi sends a simple request to toggle the relay, and the
ESP32 responds with the current light state. The ESP32 also reads a
DHT22 temperature and humidity sensor, publishing the values to MQTT
for the home dashboard. This split makes sense: the Pi handles the
user-facing logic (audio, buttons, internet radio), while the ESP32
handles the real-time hardware control.</p>

<h2>Monitoring & backup, even on tiny hardware</h2>
<p>Despite the very limited RAM, this Pi still participates in the same
Prometheus monitoring pattern as the rest of the fleet, with the metrics
collector's default configuration trimmed down to only the essential
collectors, since the full default set noticeably overloaded the CPU on
this specific board. It also runs a nightly rsync backup of its own
configuration to the NAS over the internal network.</p>

<h2>Planned next steps</h2>
<ul>
<li>Adding a USB webcam stream, mirroring the pattern already used for the 3D printer.</li>
<li>Migrating onto the planned isolated IoT network segment once that's fully set up.</li>
<li>Adding weather data from the DHT22 sensor to the LED matrix displays around the flat.</li>
</ul>

</div>