SOL-37 / HARDWARE LAB

LILYGO T-Dongle-S3 / ESP32-S3

A pocket-sized Sol node.

A thumb-drive-shaped development board rebuilt as an authenticated wireless display, cast target, physical-event source, bounded LCD/LED animation player, and electrically safe universal GPIO node for the main Sol system.

Download source 0.7.3 See physical evidence

ZIP 2,057,795 bytes / SHA-256 823c1078b6852b694c0e379c377e545332246dac8543a00f6073886e4f17503d

Wi-FiSelf-registering node
24 stepsLocal display/LED timeline
2 pinsGPIO43 and GPIO44
HMACAuthenticated session

One node, seven roles.

The firmware treats the board as a constrained capability appliance rather than a generic remote computer. It announces what it can do; Sol decides how to use it.

01 / DISPLAY

Castable media

Text, status pages, notifications, RGB565 images, QR codes, and silent video frames can be pushed through the shared Sol broadcast-display interface.

02 / INPUT

Physical events

The onboard button and watched GPIO transitions report duration, edge, logical name, monotonic timestamp, and sequence number into the Sol event bus.

03 / FEEDBACK

Local confirmation

Button and GPIO activity receives immediate on-device feedback, then fades back to the default status screen. Desktop and private phone responses stay synchronized.

04 / ANIMATION

Local timelines

Up to 24 bounded steps can coordinate LCD status, lines, progress, QR, and APA102 color without network-timed jitter. The declarative format cannot run code or touch GPIO.

05 / GPIO

Safe by default

GPIO43 and GPIO44 begin high-impedance, then apply a validated internal-pull-up button profile. Read, watch, pulse, PWM, UART, I2C, failsafe, and port.safe remain permission-gated.

06 / NETWORK

Appliance behavior

Six remembered networks, primary-profile grace, DHCP, mDNS, authenticated outbound WebSocket, reconnect backoff, event buffering, telemetry, and OTA survive ordinary power cycles.

07 / CONTROL

Unified Clock surface

The Unified Clock supplies display, LED patterns, timeline editing, GPIO, media, power-profile, response, and safety controls without exposing node credentials to browser JavaScript.

Seen, not assumed.

These are direct crops from the C615 verification camera and the live Unified Clock interface. Captions distinguish physical observation from software-reported state.

C615 camera crop showing the T-Dongle LCD with SOL ONLINE, IP address, RSSI, central time, and Samsung power profile
Default screen, physically observedC615 crop of the live dashboard: online state, DHCP address, RSSI, network-synchronized Central time, and configured Samsung 20K power profile.
Unified Clock ESP control surface showing display, power, LED, and external port controls
Unified Clock control surfaceThe host-side manual surface, captured during 0.5.2 acceptance, for the entire node: protected display, LED, GPIO, media, telemetry, and power-profile actions. The complete crop is shown without an additional page-level crop.
Second C615 camera crop showing the T-Dongle status clock at a later second
Second-accurate clock progressionA separate camera frame confirms that the on-screen Central clock advances after NTP synchronization rather than displaying a static label.
Contact sheet of C615 verification frames showing T-Dongle display content and red, green, and blue side LED states
Display and APA102 LED controlPhysical camera evidence of controlled screen changes and multiple side-LED states. Command acknowledgements alone were not treated as proof.
Cropped C615 contact sheet showing a red animation status frame, green progress frame, and the ESP control QR on the T-Dongle
Bounded animation timeline, physically observedSeparate C615 frames show a loop changing both LCD and APA102 output, followed by the on-device control QR. Red and green light visible through the case comes from the side LED.
C615 crop of the T-Dongle systems tour showing a power estimate of about 91 percent and 48 hours runtime
Live estimate stamped into the tourAt Play time, Unified Clock refreshed authenticated telemetry and resolved the current modeled value. The C615 then observed the node itself showing ~91% EST. and ~48 h; later frames explain that this is inferred, not battery telemetry.
Mobile Unified Clock animation accordion showing the expanded SOL systems tour JSON with a 3300 millisecond opening step
Phone-width systems-tour editorAll ten control panels are closed by default. This 390 by 844 acceptance view shows the 16-step, 43.2-second preset expanded without horizontal overflow.
Close camera crop of the QR code displayed on the T-Dongle screen
Internet control handoffThe camera-visible QR decoded directly to https://sol.system42.one/e; it contains no node secret or Wi-Fi credential.
Unified Clock power panel showing Samsung 20000 mAh profile and battery inference boundary
Power profile, with its uncertainty visibleThe default Samsung 20,000 mAh model can estimate a conservative energy envelope and runtime scenario. It cannot read the bank's actual state of charge through this USB-A power-only connection.

Power truth boundary.

The interface deliberately separates configured specifications and inferred runtime from measurements the hardware can actually observe.

What Sol can know

  • The selected Samsung 20,000 mAh profile and its rated 3.7 V-cell energy basis.
  • Node uptime, reboot history, network presence, RSSI, workload profile, and configured load assumptions.
  • A current modeled percentage and hours remaining from the configured start charge, elapsed load, and conversion efficiency.
  • Second-accurate Central time once the node has synchronized over the network.

What remains unknown

  • The power bank's live percentage, remaining watt-hours, cell health, or charging state.
  • Actual USB voltage/current without an external meter or sensor wired into an observable interface.
  • Whether a low-load power bank will shut itself off at a particular time.
  • A precise runtime prediction without measured load and conversion efficiency.

Signal path.

The browser never receives device credentials. All control enters through the protected host API and the node maintains the outbound authenticated session.

Public source release

Build the whole node.

The archive contains the ESP32-S3 firmware, authenticated Linux daemon, protocol documentation, host integration, service units, tests, deployment scripts, selected physical evidence, and a generic 0.7.3 firmware binary.

Download ZIP Browse ZIP Read README

Sanitized for public release: no Wi-Fi credentials, enrollment secrets, live registry, provisioned NVS state, full-flash recovery image, virtual environment, build cache, or redundant raw camera collection.