Engineered Lighting · Engineering notebook
Building the robotic spotlight¶
We're building the robotic spotlight for the Engineered Lighting fixture: a silent pan/tilt head (smart CAN servo motors, absolute encoders, no homing dance) carrying a high-CRI 3-up LED spot, living alongside the fixture's tunable-white ambient zones, exposed to Home Assistant as ordinary entities and aimed autonomously by a camera-driven perception stack — following people, lighting task surfaces and books, pointing at art when idle, never sweeping across eyes.
This ten-document series takes it from research through a working bench prototype to the system architecture, into the first hand-built fixture, and on to the integrated circuit board and the manufactured flexible wiring that replace the hand-built stack — with everything adversarially reviewed and every purchase specified.
This is our internal engineering notebook, published openly — hardware assumptions (a CUDA GPU box for Docs 5–7, an existing Home Assistant install) are ours.
What we're building toward¶
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The silent robotic spotlight
A pan/tilt head you can't hear: smart CAN actuators, absolute encoders, a balanced high-CRI LED payload — researched, chosen, bench-built, hand-soldered into a fixture that screws into a lamp socket, and then drawn as one integrated circuit board with flexible wiring to match.
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The aiming intelligence
Cameras, ground-plane tracking, and beam self-calibration that follow people, light task surfaces, and never sweep across eyes.
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The system architecture
The message contract every component obeys, and the software stack that runs it — testable without a living room.
Buying parts?¶
Everything the series tells you to buy, in one interactive list — check items off as you order, progress and totals persist in your browser.
Reading the diagrams¶
Every wiring figure in the build chapters leads with a badge — the one question that ruins first builds, answered before you read a single wire:
- Red · POLARITY / DIRECTION / POWER — getting this backwards costs hardware. Reversed motor power burns the drive; the electrolytic's stripe goes to ground; USB or the stack, never both.
- Amber · ORDER / settings — the sequence matters more than the wiring. Bridge A0 before its socket is soldered; the sniffer's terminator flips between chapters.
- Green · harmless — the mistake you don't need to fear. A swapped CAN pair just refuses to talk until you fix it.
Below each badge the pattern repeats: a schematic carries the idea, then an annotated photograph of this build's own parts carries the exact pads — so "which hole?" is answered by a picture of the hole.
The document map¶
| # | Doc | What it is | You buy |
|---|---|---|---|
| 1 | How We Got Here | Round-1 research digest: the physics, vocabulary, and five lessons under every later decision. Archive — read for understanding | nothing |
| 2 | Choosing the Motors | The decision journey to the RMD-L-4005 smart CAN actuators — what was evaluated, why integrated actuators won | (decision feeds Doc 3) |
| 3 | Build the Gimbal | 10-stage bench build: motors answering on CAN by stage 4, a balanced aimed head by stage 8. Full BoM, wiring, code, AI-partner workflow | ~$350–405 |
| 4 | Build the Full Fixture Bench | One ESP32-C6 running the whole fixture: 21 tunable-white channels + CC spotlight + gimbal, in ESPHome/Home Assistant | ~$170–240 |
| 5 | Teach It to Aim | The perception stack: cameras, ground-plane tracking, beam self-calibration, coordination, safety, user stories, phased roadmap (Phase 0 = a weekend) | ~$120–320 per room |
| 6 | The Message Contract | The one page every component obeys: topics, schemas, units, watchdogs, and the dual-control architecture (HA entities + autonomy without fights). When docs disagree, Doc 6 wins | nothing |
| 7 | Building the Software | The code: pinned stack, repo layout, hardware-free testing (replay cameras, simulated fixtures), deployment, firmware growth path, licensing gates | nothing |
| 8 | Build the Fixture | Six wiring steps from breadboard to a hand-soldered fixture that screws into a lamp socket — stacked protoboards, a wiring map, and a diagram per step | ~$105–120 |
| 9 | Understand the PCB | The integrated LIGHT v0.2 board: an interactive viewer of the real eight-layer PCB, 262 features, the 20-sheet schematic, the exact parts list and KiCad sources. Designed — not built, not powered | nothing yet |
| 9a | PCB Build Shopping List | Parts for two complete fixtures alongside the assembled PCBs: motors, optics, diffuser, connectors, wire and mounting supplies. Check off purchases; see which selections remain open | check current supplier prices |
| 10 | The Flex Circuits | Three passive flexible circuits that replace the fixture's hand-cut wiring: an arm ribbon and two cylinder bands, drawn against the main board's own connector pinmaps and checked digitally. Routed and quoted — none has been made | nothing yet |
Each build doc travels with connector-level companions — 3c · 3a · 3b for the gimbal, 4a · 4b for the bench — the pages that hold the parts in your hands. The sidebar groups them in build order.
Reading paths: Building this weekend? → Doc 3, then 4 (skim their concepts sections; Docs 1–2 optional background). Understanding the choices? → 1 → 2, then skim 5. Writing the software? → 6 → 7, with 5 as the spec. Making it permanent? → 8, once 4's checklist passes. Understanding the real PCB? → 9, which explains the integrated board part by part, then 10 for the flexible wiring that plugs into it.
Total prototype budget, all hardware: roughly $745–1085 for one room end-to-end · Current phase: bench bring-up — first motor motion 2026-07-31 (Doc 3 stage 4)