A tiny always-on TFT in the rack that shows UniFi Wi‑Fi client counts and whether the internet is up — fed by Home Assistant over MQTT. No laptop, no UniFi UI.

Why it exists

UniFi and Home Assistant already know who’s on the network. I still end up opening a browser to answer dumb questions: How many clients are on Main? Is Guest quiet? Did the WAN drop? Jimbo’s Rack answers that from three feet away on a Feather TFT sitting in the rack.

Hardware

• Adafruit ESP32‑S2 Reverse TFT Feather
• Built-in 1.14″ 240×135 TFT (ST7789)
• Wi‑Fi (no Bluetooth on S2), USB‑C, STEMMA QT / Qwiic for future sensors
• 4 MB flash, 2 MB PSRAM, on-board battery charging if I ever run it soft-mounted

Dev environment is OpenSUSE Tumbleweed with VS Code + PlatformIO (Arduino framework). CircuitPython is fine for prototypes; this project is compiled C++ so redraw and MQTT stay snappy.

Architecture

UniFi → Home Assistant (client-count entities) → MQTT broker → ESP32 → TFT. HA owns the “truth,” the Feather is just a dumb bright display. That means I can change which networks map to which lines without reflashing firmware — swap the entity IDs in the HA automation.

Publish cadence is about every 10 seconds on these topics (names only — no host/creds here):

• jimborack/main_clients — integer
• jimborack/pod_clients — integer
• jimborack/guest_clients — integer
• jimborack/internet — online / offline (also accepts on/true/1)

What the screen shows

• Main — client count on the main SSID/network
• Internet — green Online / red Offline
• Pod — client count on the pod network
• Guest — client count on guest

State lives in a small DashboardState struct (client ints, internet bool, MQTT connected flag, redraw flag). MQTT callbacks mutate that struct; the display loop only repaints when something actually changed.

Firmware layout

PlatformIO project shape (credentials stay local, never committed for publish):

• platformio.ini — board = Adafruit ESP32‑S2 TFT Feather
• include/dashboard.h — shared display state
• include/config.example.h — template for Wi‑Fi / MQTT (real config.h stays private)
• src/mqtt.cpp — subscribe + parse the four topics
• src/display.cpp — labels/values on the ST7789
• Wi‑Fi connect + NTP time sync on boot

Home Assistant side

Automation alias along the lines of “Jimbo Rack MQTT Stats”: time-pattern trigger every 10s, then four mqtt.publish actions. Payload for clients is {{ states('sensor.…') }} for each UniFi client-count entity; internet payload is a simple online/offline string. Search HA for your exact Wi‑Fi / VLAN sensor names — they vary by UniFi / HA integration setup.

What’s working vs next

• Done: PlatformIO toolchain, TFT bring-up, Wi‑Fi, NTP, MQTT, live numbers on glass
• Next: OTA updates so I am not hunting a USB cable in the rack
• Next: multi-page UI (Network / HA / servers / environment)
• Next: rack temp + fan control once the sensor / EMC2101 path is sorted
• Next: tiny history graphs; WAN-down / UPS / garage-door notification flashes
• Next: captive config page for Wi‑Fi/MQTT so secrets aren’t compile-time forever

Related projects: Home Assistant and UniFi.