StatNode

Live PC sensor monitor for small ESP32 color displays. A companion app on your PC streams sensor readings (CPU, GPU, RAM, temps, fans, power, ...) over the LAN; the device renders them on a small color panel with selectable "faces", a web config portal, and animated idle clocks.

Firmware only talks UDP to the companion. No cloud, no accounts.

StatNode is the color evolution of my SmallOLED-PCMonitor, the 128x64 OLED variant, which is still actively developed.

Monitor faces

A face is two settings, not one: a layout says how the bound metrics are arranged, a surface says how that arrangement is painted. Four layouts by four surfaces gives twelve faces, all driven by the same eight ordered metric slots (slot 1 = hero). Switch face live from the web portal.

	Flat	Aero glass	Liquid glass	Load wash
Big numbers	Big numbers	-	-	-
Tiles	Tiles	Aero glass tiles	Liquid glass tiles	Pulse
Strips	Strips	-	-	Washed strips
Duo	Duo, Hero + list	Aero glass duo	Liquid glass duo	Washed duo

How many readings appear is simply how many slots you bind, and every face lays itself out from that count, so there is no separate "tile count" setting to disagree with your bindings. The Duo layout adds two options of its own: how many hero bands it opens with (one or two), and whether the remaining metrics fill a grid or full-width list rows. One band plus list rows is the face previously called Hero + list.

Values are rendered from native font faces sized to the space they have, never magnified, so the big readings stay crisp on the small square panels as well as on the 320x480 Guition.

Big numbers	Tiles	Aero glass tiles
Liquid glass tiles	Pulse	Strips
Washed strips	Hero + list	Duo
Aero glass duo	Liquid glass duo	Washed duo

_{Captured on the 320x480 Guition through /screen.bmp, default colorway.}

Panel sizes

The same face responds to the space available instead of stretching a fixed design. These metric views were captured from the actual 240x240 ESP32-S3 and 320x480 Guition devices while both were receiving the same companion feed.

Liquid glass Duo, 240x240	Liquid glass Duo, Guition 320x480
Pulse, 240x240	Pulse, Guition 320x480

Surfaces

Flat paints in the colors from the portal's Colors page. Load wash tints each slot's ground by its own reading, quantized into eight steps with hysteresis so a value sitting on a boundary does not flicker between them; it is built for reading the machine's state from across the room rather than reading digits.

The two glass surfaces render every card as a pane over a generated backdrop: Aero glosses the face of each pane, Liquid leaves the face clear and lights the edges. The backdrop is a smooth vertical gradient, composed well above the panel's color depth and dithered on the way down to it, so the panes stay banding-free.

Both take a colorway, set on the portal's Display page: Default, which follows your background color as smoked glass, and two frosted presets. Gloss, bow and chart fill are sliders on the same card and apply live as you drag them. The colorway applies to whichever layout is wearing the glass.

Default	Frosted glass dark	Frosted glass light

_{Top row Aero, bottom row Liquid, captured on the 320x480 Guition. That board has PSRAM, so these are true 16-bit captures with no color shift.}

Charts on every face glide between packets rather than stepping, and the frame interval is paced off what the last frame actually cost, so a heavy face on a big panel slows itself down instead of starving WiFi.

When the PC goes offline the screen shows an idle clock: Standard, Breakout, or an animated Runner face (portal, Clock page).

Web portal

Browse to the device IP or http://statnode.local. Everything is applied live without a reboot (except network changes).

Overview	Display	Metrics & layout

Pages: Overview (live preview + health), Display (face, brightness, night schedule), Metrics & layout (drag metrics into slots), Colors (theme presets + contrast check), Clock, Hardware (touch pad, status LED), Network, Maintenance (config backup/restore, factory reset, OTA).

Optional peripherals

Both are off by default and configured on the portal's Hardware page. Only GPIOs that cannot break the display, USB or boot are offered, and the page lists the allowed pins for your board.

• Capacitive touch pad (TTP223): assign a tap and a hold action - next or previous face, toggle the idle clock, or switch the display off. You choose which faces the cycling walks through.
• Status LED: a single-color LED on a GPIO, driven through a transistor and dimmed by PWM (not an addressable strip). It has its own night level, can go dark whenever the display is dark, and can go dark while the PC is offline. The brightness slider drives the real LED live while the page is open.

How it works

PC companion app  --UDP :4210 JSON-->  ESP32  -->  color panel + web portal

The companion (StatNode Companion) discovers PC sensors, lets you pick which to send, and pushes a JSON packet each second. The device binds each metric by id to a display slot. If packets stop, it flips to the idle clock.

The PC and the device must be on the same LAN/subnet, with UDP port 4210 reachable from the PC to the device.

Sensor source (Windows): LibreHardwareMonitor

On Windows the companion reads its sensor data from LibreHardwareMonitor (LHM), so LHM must be running for readings to appear. Run it as administrator for full CPU/GPU/board coverage, then either:

• REST API (default, LHM 0.9.5+): enable Options > Remote Web Server (port 8085). The companion prefers this and reads /data.json.
• WMI: the companion falls back to the root\LibreHardwareMonitor namespace.

The device's status dot shows LHM off (red) when LHM is not running. On Linux the companion reads sensors directly and does not need LHM.

Companion app

Source and a prebuilt Windows build live in this repo under StatNode-CompanionApp/.

• Windows: run win-companion/dist/StatNodeCompanion.exe, or from source python win-companion/statnode_companion.py (deps in win-companion/requirements.txt).
• Linux: python linux-companion/statnode_companion_linux.py (deps in linux-companion/requirements.txt).

It opens a local UI at http://127.0.0.1:8740 where you pick the target device, choose which sensors to stream, and set the send interval. See the companion README for details.

Supported hardware

Env	Board	Panel
esp32s3 (default)	LOLIN ESP32-S3 Mini + ST7789	240x240
esp32s3_zero	Waveshare ESP32-S3-Zero + ST7789	240x240
ws_lcd_154	Waveshare ESP32-S3-Touch-LCD-1.54	240x240
esp32c3	LOLIN ESP32-C3 Mini + ST7789	240x240
jc3248w535	Guition JC3248W535 (3.5", 16MB / 8MB PSRAM)	320x480

The faces lay themselves out from the live canvas size, so both the 240x240 square panels and the larger 320x480 Guition are first-class. Rotation is a runtime setting, so the Guition can be mounted portrait or landscape.

Wiring

For the Super Mini boards you solder a bare ST7789 240x240 SPI module to the GPIOs below (SPI, no MISO). ws_lcd_154 and jc3248w535 are integrated boards; their panels are already wired, nothing to connect.

ST7789 module	esp32c3	esp32s3 / esp32s3_zero
GND	GND	GND
VCC	3V3	3V3
SCL / SCLK	GPIO21	GPIO12
SDA / MOSI	GPIO20	GPIO11
RES / RST	GPIO10	GPIO8
DC	GPIO7	GPIO9
CS	GPIO6	GPIO10
BLK (backlight)	GPIO5	GPIO13

Pins are set in src/lgfx_boards.h (backlight in platformio.ini). Power the panel from 3.3V, not 5V.

Flashing a prebuilt binary

Releases ship two files per board: firmware-<version>-<env>.bin (full image) and OTA_ONLY_firmware-<version>-<env>.bin (for the portal's Maintenance page). Pick the file matching your board's env from the hardware table.

Web flasher (esptool-js):

1. Visit the ESP Web Flasher in desktop Chrome or Edge (Web Serial is required, so Firefox, Safari and mobile won't work).
2. Connect the board via USB. If it constantly connects/disconnects, hold the BOOT button, connect to USB while still holding it, then release after connecting. Alternatively, hold BOOT, press RESET while holding BOOT, then release both buttons.
3. Click "Connect" and select your port.
4. Click "Choose File" and select the full image for your board, e.g. firmware-v1.2.0-esp32c3.bin. Make sure the env matches your board, or the screen will stay black.
5. Set Flash Address to 0x0.
6. Click "Program" and wait ~30 seconds.
7. Done! Continue with First-run setup.

Manual: esptool.py --chip esp32c3 --port COM3 --baud 460800 write_flash 0x0 firmware-v1.2.0-esp32c3.bin (use --chip esp32s3 for the four S3 boards).

Build & flash

Built with PlatformIO.

# build the default env
pio run

# build + USB flash a specific board
pio run -e esp32c3 -t upload

# OTA update an already-running device
curl -F "firmware=@.pio/build/esp32c3/firmware.bin" http://<device-ip>/ota/upload

# package release binaries (all envs, output in release/<version>/)
python create_firmware.py

First-run setup

1. Flash the firmware and power the device.
2. On first boot it opens a WiFi AP StatNode-XXXX (password statnode1234). Connect and the captive portal opens at http://192.168.4.1; enter your WiFi. (Improv-over-USB-serial also works in the first 3 minutes.)
3. After it joins your network, open the device IP / statnode.local, bind your metrics on Metrics & layout, and start the companion.

Troubleshooting

• Screen stuck on the idle clock / no metrics: the device is not receiving packets. Check the companion is running and pointed at the device IP, that LHM is running (Windows), and that the PC and device share the same subnet with UDP 4210 open.
• statnode.local does not resolve: use the device IP directly (shown on the device at boot). mDNS must be enabled (default on) and is flaky on some networks.
• Colors look off in a /screen.bmp capture: expected. The capture is RGB332-quantized; the panel itself is full color.

Credits

Built on LovyanGFX, ArduinoJson, and Improv WiFi (vendored under lib/ImprovWiFi).