Balkon Pi
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.
What it does
- Audio output 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.
- Physical controls: a push button for the balcony light and a toggle switch for music playback, read directly via GPIO.
- HTTP communication with an ESP32-based balcony light controller.
- Internet radio via a lightweight command-line audio player, controlled by a small custom tool ported from an earlier bathroom-Pi project.
Hardware details
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.
Monitoring & backup, even on tiny hardware
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.
Planned next steps
- Adding a USB webcam stream, mirroring the pattern already used for the 3D printer.
- Migrating onto the planned isolated IoT network segment once that's fully set up.
- Adding weather data from the DHT22 sensor to the LED matrix displays around the flat.