Media: finalize Internet of Things lesson (esp32/iot.md)

[jonfroehlich]

Media shot-list for esp32/iot.md (Internet of Things). Part of the draft-lesson finalization tracked in #122. Live on main with the "in draft form" banner. Prose is complete; it needs diagrams + workbench/dashboard capture.

Note: on the esp32-bluetooth branch this page is re-parented under the new Wireless sub-module (L1). Media work here applies regardless of where it lands in nav.

Already present

• Hero exists ✅ — YouTube demo (DgCFUHGSKSM): ESP32 streaming photoresistor data to an Adafruit IO dashboard.
• IDE library-install screenshots; Huzzah32 Fritzing circuit (in a collapsible).
• Generic placeholders in materials table.

Shot list — desk work (drawable in software)

• Fritzing wiring diagram: ESP32-S3 Feather + photoresistor divider (A5/ADC1) + LED on GPIO13 w/ 220Ω; call out the ADC1-vs-ADC2 constraint. (iot.md:194 TODO)
• Screenshot sequence: Adafruit IO dashboard walkthrough (login → feed → dashboard → line chart → gauge).
• Screenshot: completed dashboard (line chart + gauge side by side). (iot.md:422 TODO)
• (Optional) Screenshot: toggle block config for the bidirectional led-control feed.

Shot list — bench/capture (real circuit + screen recording)

• Workbench video (~15–20s): cover/uncover photoresistor, LED responds.
• Split-screen video (~30–40s): bench (shading sensor) + live Adafruit IO dashboard updating.
• Bidirectional video (~15–20s): toggle on dashboard → onboard LED on/off (note the network latency). (iot.md:491 TODO)

Suggested hero

Keep the existing YouTube demo as hero — it already shows the end-to-end system. Optional caption polish:

In this lesson, we'll build a full IoT system: the ESP32 reads ambient light, streams it to the cloud over WiFi, and displays it live on an Adafruit IO dashboard.

Placement (hero-first standard)

Put the hero block immediately after the TOC --- — before any intro prose, the draft banner, or note box (slot: TOC → hero → optional note → prose; see #123). Markup: <video autoplay loop muted playsinline aria-label="..."> for a local clip (use controls instead of autoplay if it has audio), or <div class="iframe-container"><iframe ... title="descriptive..."></iframe></div> for YouTube — followed by a **Video.**/**Figure.** caption with {: .fs-1 }.