LED wiring conversation

Use serial for data, parallel for power. Keep the power brick off the sculpture; the heavy LED current never passes through the ESP32.

AC outlet
   │
5 V / 10 A brick — secured on floor/wall
   │
7.5 A fuse
   │  12 AWG trunk along one suspension cable
   ▼
small enclosure at the LED seam
   ├── power bus ──► both ends of both strips
   ├── small controller-power branch ──► ESP32
   └── ESP32 data/clock ──► outer strip ──► inner strip

1. Series or parallel

Power is parallel:

• Every strip connection receives the same 5 V and GND.
• Feed both ends of each strip. Since all four strip ends return to the physical seam, this is conveniently one distribution point.
• Never connect the strips in series for power.
• Use only one 5 V supply and make all grounds common.

Data and clock are serial:

ESP32 GPIO 23 ──► outer DI
ESP32 GPIO 18 ──► outer CI

outer DO ──► inner DI
outer CO ──► inner CI

inner DO/CO: unused

That makes the outer face pixels 0–298 and the inner face 299–582, matching the firmware. Parallel data would merely mirror the faces and prevent independent control.

Lay both strips with their arrows going the same physical direction around the spine. Do not connect the inner strip’s final data output back to the beginning.

2. Power and the block

The current design is 583 pixels with a firmware limit of 7 A, as recorded in params.py. Without that limiter, theoretical full white is roughly 35 A, so the limiter is essential.

Your 5 V / 10 A supply is adequate for the intended 7 A build. I would not buy a larger one. However, the existing barrel plug and screw-terminal adapter are only about a 5 A connection. Therefore:

• For the easiest initial build, set the current limit to about 4.5 A and retain the barrel connector.
• For the intended 7 A build, replace the DC connection with something rated comfortably above 7 A—XT60, Anderson Powerpole, or direct covered terminals—and use the 7.5 A fuse described in BUILD.md.
• Put the fuse near the supply, before the long cable, so it protects that cable too.

The block is indeed the AC/DC converter. It should not hang from the artwork or from its electrical cord. Recommended arrangement:

• Brick on the floor, wall, shelf, or otherwise independently secured.
• A low-voltage cable runs up alongside one suspension cable.
• Use 12 AWG pure-copper two-conductor cable for a run of up to roughly 10 feet at 7 A. At that distance its calculated drop is about 0.22 V.
• 14 AWG is reasonable for approximately 5 feet.
• The existing 18 AWG recommendation applies only to short injection branches on the sculpture, not a floor-to-ceiling feed. Southwire’s voltage-drop calculator is useful for the final measured distance.

If the brick must be near the ceiling, secure it independently, keep it ventilated and accessible, and do not bury it inside a closed canopy. Running 12 or 24 V upward and converting to 5 V near the sculpture can use thinner cable, but it adds another converter and heat source; this piece is small enough that 12 AWG at 5 V is simpler.

3. Wire at the ESP32

The heavy power wire does not connect to the ESP32:

• Supply-to-sculpture trunk: 12–14 AWG.
• Short power injection branches: 18–20 AWG.
• ESP32 clock, data and signal ground: 22–24 AWG is plenty.

Dupont jumpers are electrically adequate for clock/data during testing, but mechanically poor for a hanging installation. For the finished controller, use either:

• An ESP32 screw-terminal breakout matching your exact 30- or 38-pin board, or
• A female header/perfboard with 22–24 AWG wires soldered to it, terminating in a locking JST-style connector.

Put the ESP32 and preferably a 74AHCT125 level shifter in a small enclosure at the strip seam. That keeps the 8 MHz clock/data leads short. Use strain relief so no connector carries cable weight.

For standalone operation, the ESP32 can use a separately fused approximately 1 A branch from the same 5 V bus. Connect that through its USB socket or its 5V and GND pins—never 3V3. Espressif specifies that USB, 5 V-pin and 3.3 V-pin power are mutually exclusive, so disconnect external board power before plugging in a programming USB cable. Espressif ESP32-DevKitC power guidance

Before taping the LEDs

A few important mechanical details:

• Choose the electrical seam first, preferably near the suspension cable carrying power.
• Dry-fit before cutting. The calculated counts are 299 outer and 284 inner, but the built spine now wins over the model. Do not trim solely from those nominal numbers.
• Leave the first and last several inches loose at the seam for soldering, testing and strain relief.
• Let the strip pair naturally rotate around the round rail as you advance. The design relies on that relaxed Frenet orientation; forcing a constant “up” direction will torque the strip and spine.
• Self-fusing tape is fine for the initial installation. Use narrow bands between LEDs, wrap completely around the assembly, and do not stretch the LED strips longitudinally.
• Test the full chain at 20% before making permanent connections. Then add both-end power injection and test progressively toward the 7 A limit before installing the diffuser or final clips.
• After installation, record the actual outer and inner pixel counts and update MEASURED_PX_OUTER, MEASURED_PX_INNER, and the measured spine length in params.py.

The 74AHCT125 goes in the small controller enclosure between the ESP32 and the first LED strip. It only level-shifts clock/data; LED power does not pass through it.

For a bare 14-pin DIP chip, mount it in a 14-pin socket on perfboard. Orient the notch upward:

                     notch
                ┌─────∪─────┐
 GND ───────────┤1  /1OE VCC 14├────────── 5 V
 GPIO 18 ───────┤2   1A /4OE 13├────────── 5 V
 strip CI ◄─330Ω┤3   1Y   4A 12├────────── GND
 GND ───────────┤4  /2OE  4Y 11├────────── unused
 GPIO 23 ───────┤5   2A /3OE 10├────────── 5 V
 strip DI ◄─330Ω┤6   2Y   3A  9├────────── GND
 GND ───────────┤7  GND   3Y  8├────────── unused
                └──────────────┘

Also solder a 0.1 µF ceramic capacitor directly between pins 14 and 7.

The essential connections are:

• Pin 14 → LED supply 5 V
• Pin 7 → common ground
• Pins 1 and 4 → ground, which enables the two channels
• GPIO 18 → pin 2 → pin 3 → outer-strip CI
• GPIO 23 → pin 5 → pin 6 → outer-strip DI
• ESP32 ground, shifter ground and strip ground must all be connected
• Outer-strip DO/CO then connects directly to inner-strip DI/CI

The two 330 Ω output resistors are inexpensive protection against ringing; place them close to pins 3 and 6. They can be omitted temporarily for very short breadboard testing.

Physically:

1. Prototype it on a solderless breadboard.
2. For the final version, solder a DIP socket, capacitor, resistors and connectors onto perfboard.
3. Put the chip into the socket only after soldering.
4. Use 22–24 AWG wire for these signals.
5. Keep the shifter-to-first-LED wires short—ideally under 20–30 cm.
6. Enclose and strain-relieve everything near the LED seam.

If yours is a tiny SOIC/TSSOP chip rather than the large through-hole DIP version, use a matching SOIC/TSSOP-to-DIP breakout board; don’t attempt to attach individual hanging wires to those legs. A ready-made breakout labeled OE, A, and Y uses the same mapping: ESP32 connects to A, strip connects to Y, and OE goes low.

Make sure it says 74AHCT125, not merely 74AHC125. The T version has the TTL-compatible input threshold that reliably recognizes the ESP32’s 3.3 V output while powered at 5 V. The pinout and active-low enable behavior come directly from the TI SN74AHCT125 datasheet.

Yes. For more than about 10–15 feet, distribute at 24 V and convert to 5 V at the sculpture. This is the standard solution.

wall
 │
24 V / 3 A AC-DC brick — remote
 │
3 A fuse
 │  16–18 AWG cable, potentially quite long
 ▼
24 V → 5 V DC/DC converter at sculpture
 ├── 7.5 A fuse ──► LED power bus
 └── 1 A fuse ────► ESP32 + 74AHCT125

Why it works: your LEDs need at most about 35 W. At 5 V that is 7 A; at 24 V it is only about 1.7–1.9 A after conversion losses. Voltage drop and cable heating fall dramatically.

For comparison, using one-way cable distances:

A suitable converter specification is:

• Input: approximately 18–36 VDC
• Output: regulated 5 V
• Continuous output: at least 10 A
• Power: preferably 60 W
• Overload, thermal and reverse-polarity protection
• Screw terminals or another properly rated connection

A reputable example is the Mean Well RSD-60G-5: 9–36 V input, 5 V/12 A output, 60 W, approximately 128 × 60 × 25 mm. Its published efficiency at 24 V is about 88%. Official RSD-60 datasheet

It is smaller and flatter than an AC brick, but it will dissipate several watts of heat. Mount it in the controller enclosure near the seam with ventilation and strain relief. It is not weatherproof by itself.

Important details:

• The 24 V cable connects only to the converter input—never directly to the LEDs or ESP32.
• The converter’s 5 V output must be verified before connecting anything.
• Keep the 5 V wires from converter to LED distribution very short and use 16–18 AWG.
• The ESP32, 74AHCT125 and LEDs all share the converter’s 5 V-side ground.
• Continue powering both ends of each LED strip.
• Keep the firmware’s 7 A limit.
• Use different, polarized connectors for 24 V and 5 V so they cannot accidentally be interchanged.
• Cable routed inside walls or ceilings must have the appropriate in-wall rating.

So the practical choices are:

1. Up to about 10 feet: retain the 5 V brick and use 12 AWG.
2. Longer than that: replace the brick with a 24 V/3 A brick and put a 24→5 V, 60 W converter beside the ESP32.
3. Alternatively, extend AC and put the existing 5 V brick closer—but then you still have to hide and securely mount the large block near the sculpture.

For your priorities—long distance and no big AC block above the piece—I would choose the 24 V system.

It is the right type, voltage and nominal capacity—and its 64 × 53 × 20 mm size is much easier to hide. I’d use it for prototyping, but validate it before trusting it unattended overhead.

At our 7 A LED limit plus the ESP32, it would deliver approximately 38 W, about 75% of its claimed 50 W capacity. From a 24 V source it should draw roughly 1.8–2 A.

Wire it as printed, noting that the output polarity order is reversed:

Left to right terminals:

24V+   24V−    5V−    5V+

Use:

24 V / 3 A brick
   │
3 A input fuse
   │ long 16–18 AWG cable
   ▼
TOBSUN input +/−
   │
TOBSUN output +/−
   ├── 7.5 A fuse ──► LED distribution
   └── 1 A fuse ────► ESP32 + 74AHCT125

Use 24 V, not 12 V, for the long cable. Use short 16 AWG wires from the converter’s 5 V output to the distribution point, preferably with crimp ferrules under those screw terminals.

My reservation is documentation: I could not find a real manufacturer datasheet, thermal derating curve, ripple specification, efficiency curve or independently documented protection behavior for the EA50-5V. “10 A max” may not mean 10 A continuous, particularly inside a small potted plastic enclosure. There are also anecdotal reports of noise problems with this exact model, although that does not prove every unit is problematic.

Before accepting it:

1. With nothing connected, verify output polarity and approximately 5.0 V.
2. Start with the firmware limit at 4 A.
3. Run the Flat White test for 30 minutes.
4. Raise the limit to 7 A and run it for at least one hour in the actual enclosure and ambient conditions.
5. Confirm the 5 V output remains stable under load and that there are no ESP32 resets, flickering or color changes.
6. Measure case temperature with an IR thermometer. As a conservative acceptance criterion, I would reject it if the case exceeds roughly 60–65°C, becomes too hot to hold, or its output noticeably sags.
7. Repeat after several cold starts, because startup is often where marginal converters misbehave.

Do not enclose it airtight despite the claimed waterproof/potted construction; it still needs to release heat, and the exposed terminal block is not waterproof.

Verdict:

• Temporary/testing installation: yes, reasonable.
• Final installation after a successful full-load thermal test: probably acceptable, especially with the 7 A software limit and fuses.
• Unattended permanent installation where failure would be expensive: I’d still prefer the documented Mean Well RSD-60G-5, whose official rating is 5 V/12 A continuous with specified thermal behavior and protection. Mean Well datasheet

If compactness matters most, this TOBSUN is worth trying—but buy a spare and qualify both units rather than assuming the printed rating.

Below is the complete electronics BOM for the long-distance power arrangement:

120 VAC → remote 24 V brick → long 24 V cable
→ local 24-to-5 V converter
→ LEDs + ESP32 + 74AHCT125

Cross off the items you already have.

Core electronics

Only one 74AHCT125 is needed. It connects between the ESP32 and the outer strip; the outer strip then drives the inner strip.

Power conversion

Converter choices:

• Compact/testing: TOBSUN EA50-5V, 5 V/10 A. Buy two, qualify both, install the cooler/more stable unit and retain the other as a spare.
• Documented/permanent: Mean Well RSD-60G-5, 5 V/12 A, 60 W. One is sufficient. Official datasheet

A good documented brick option is the Mean Well GST90A24-P1M, rated 24 V/3.75 A. It uses a center-positive 5.5 × 2.5 mm plug. Official datasheet

The existing 5 V/10 A brick remains useful for bench testing, but it is not used in the final long-distance 24 V arrangement.

Fuses and distribution

Instead of bus blocks, use:

• Four WAGO 221-415 five-port lever connectors
• Two WAGO 221-413 three-port connectors
• WAGO mounting carriers

All fuse holders and switches on the 24 V side must be DC-rated to at least 32 V.

Wire

Do not use copper-clad aluminum wire. The long cable length is the one-way physical run; voltage calculations include the return conductor automatically.

If the cable goes inside a wall or ceiling, use appropriately listed CL2/CL3/in-wall cable rather than ordinary silicone hookup wire.

Connectors and wiring hardware

The trimmed outer and inner strip tails will lose their factory end wiring. You will need to solder new power pigtails to both cut ends, plus DO/CO from the outer tail to DI/CI at the inner input.

Enclosure

Use plastic rather than metal around the ESP32’s antenna. Do not make the converter compartment thermally airtight. The exposed screw terminals on the TOBSUN are not waterproof even if its potted body is advertised as IP68.

Useful but optional

Do not buy the TOBSUN “15 A” version merely because it is only slightly more expensive. The firmware remains limited to 7 A, and the 10 A model already has sufficient nominal headroom.

Tools needed, but not installed in the piece

• Digital multimeter
• IR thermometer for converter load testing
• Temperature-controlled soldering iron
• Wire stripper
• Ratcheting ferrule crimper
• JST/crimp-terminal tool if using loose contacts
• Heat gun
• Small torque screwdriver or correctly sized normal screwdriver
• Flush cutters

The three indispensable safety items are the multimeter, correct fuses, and strain relief. Verify polarity and 5 V output before connecting either strip or the ESP32.

That barrel connector is fine here. The earlier barrel problem was specifically 5 V at 7 A. With 24 V distribution, this build draws only about 1.8–2 A through the barrel, well within a decent 5.5 × 2.5 mm connector’s capability.

Use it like this:

Aclorol 24 V/4 A brick
   │
5.5 × 2.5 mm barrel plug
   │
matching 5.5 × 2.5 mm female adapter
   │
3 A blade fuse
   │
long 16/2 cable
   │
XT30 disconnect at sculpture
   │
24→5 V converter

Important details:

• Use the included female adapter only if it is genuinely 5.5 × 2.5 mm. A 5.5 × 2.1 mm socket may seem to fit but will be loose and intermittent.
• Verify center-positive polarity from the brick’s label and again with a multimeter.
• Put the 3 A fuse immediately after the female barrel adapter.
• Secure the barrel connection inside a small junction box or clamp both cables so it cannot separate mechanically.
• The supply’s 96 W rating is harmless—the load takes only what it needs.
• A 3 A fuse should tolerate the expected ~2 A input while protecting the cable if something faults.
• The long cable remains 16 AWG through approximately 50 feet, or 14 AWG beyond that.

You do not need an XT connector at the brick unless you want one. The included barrel-to-screw adapter can transition directly into the fuse and long cable. Keep the XT30 at the sculpture for convenient removal.

The only remaining concern is supply quality, not the barrel. Check the physical brick for an actual UL or ETL safety mark. I couldn’t verify a manufacturer datasheet or formal safety listing for Aclorol. Since this is the mains-connected component, I would use it only after checking the label and load-testing it; for a permanent unattended installation, a documented adapter such as the Mean Well GST90A24-P1M is the safer choice.

So: electrically, the Aclorol specification and barrel are suitable. The barrel does not need replacing merely because it is a barrel.

flowchart TB
    subgraph REMOTE["REMOTE POWER — floor, wall, or secured shelf"]
        AC["AC1 — 120 V wall outlet"]
        PS1["PS1 — Aclorol AC/DC adapter<br/>100–240 VAC → 24 VDC, 4 A"]
        J1["J1 — 5.5 × 2.5 mm female barrel adapter<br/>Verify polarity with multimeter"]
        F1["F1 — 3 A blade fuse<br/>Fuse positive conductor only"]
        W1P["W1+ — long-run positive conductor<br/>16 AWG ≤50 ft; 14 AWG beyond"]
        W1N["W1− — long-run return conductor<br/>Same gauge as positive"]

        AC -->|"AC power"| PS1
        PS1 -->|"24 V barrel plug"| J1
        J1 -->|"+24 V"| F1
        F1 --> W1P
        J1 -->|"24 V return"| W1N
    end

    subgraph LOCAL["LOCAL ELECTRONICS — enclosure at sculpture/seam"]
        X1["X1 — XT30 locking disconnect<br/>24 V pair"]
        U1["U1 — TOBSUN EA50-5V converter<br/>24 V → regulated 5 V, 10 A max<br/>Terminals left→right: IN+, IN−, OUT−, OUT+"]
        F2["F2 — 7.5 A blade fuse<br/>LED branch"]
        F3["F3 — 1 A fuse<br/>Controller branch"]
        P5["5V+ BUS — covered distribution block/WAGO"]
        G5["GND BUS — common 5 V-side ground"]
        C1["C1 — 1,000 µF ≥10 V electrolytic<br/>C1 + → 5V bus; C1 − → GND"]

        W1P -->|"+24 V"| X1
        W1N -->|"24 V return"| X1
        X1 -->|"IN+ and IN−"| U1

        U1 -->|"OUT+ · short 16 AWG"| F2
        F2 --> P5
        U1 -->|"OUT+ · short 22 AWG"| F3
        U1 -->|"OUT−"| G5

        P5 -->|"+"| C1
        G5 -->|"−"| C1
    end

    subgraph CONTROLLER["CONTROLLER — powered from local regulated 5 V"]
        ESP["U3 — ESP32 Dev Module<br/>5V/VIN pin and GND<br/>GPIO18 = clock; GPIO23 = data"]
        CTL5["Protected controller 5 V"]
        U2P["U2 — 74AHCT125, PDIP-14<br/>Pin 14 → 5 V · Pin 7 → GND<br/>Pins 1 & 4 /OE → GND<br/>Pins 10 & 13 unused /OE → 5 V<br/>Pins 9 & 12 unused inputs → GND<br/>Pins 8 & 11 unused outputs → NC"]
        C2["C2 — 0.1 µF ceramic<br/>Directly between U2 pins 14 and 7"]
        U2C["U2 channel 1 — CLOCK<br/>Pin 2 = 1A input<br/>Pin 3 = 1Y output"]
        U2D["U2 channel 2 — DATA<br/>Pin 5 = 2A input<br/>Pin 6 = 2Y output"]
        R1["R1 — 330 Ω<br/>Clock series resistor"]
        R2["R2 — 330 Ω<br/>Data series resistor"]

        F3 --> CTL5
        CTL5 -->|"5V/VIN"| ESP
        G5 -->|"GND"| ESP
        CTL5 -->|"Pin 14"| U2P
        G5 -->|"Pin 7 and enabled /OE pins"| U2P
        CTL5 -->|"+"| C2
        G5 -->|"−"| C2

        ESP -->|"GPIO18 · 3.3 V clock"| U2C
        ESP -->|"GPIO23 · 3.3 V data"| U2D
        U2C -->|"Pin 3 · 5 V clock"| R1
        U2D -->|"Pin 6 · 5 V data"| R2
    end

    subgraph LEDS["LED ASSEMBLY — two serial-data faces, parallel power"]
        OI["Outer strip INPUT end<br/>SK9822 pixels 0–298<br/>5V · GND · CI · DI"]
        OO["Outer strip OUTPUT end<br/>5V · GND · CO · DO"]
        II["Inner strip INPUT end<br/>SK9822 pixels 299–582<br/>5V · GND · CI · DI"]
        IO["Inner strip OUTPUT end<br/>5V · GND<br/>CO/DO left unconnected"]

        OI -->|"Data propagates through outer strip"| OO
        OO -->|"CO → CI · DO → DI"| II
        II -->|"Data propagates through inner strip"| IO
    end

    P5 -->|"18 AWG injection +"| OI
    P5 -->|"18 AWG injection +"| OO
    P5 -->|"18 AWG injection +"| II
    P5 -->|"18 AWG injection +"| IO

    G5 -->|"18 AWG injection −"| OI
    G5 -->|"18 AWG injection −"| OO
    G5 -->|"18 AWG injection −"| II
    G5 -->|"18 AWG injection −"| IO

    R1 -->|"22–24 AWG · CI"| OI
    R2 -->|"22–24 AWG · DI"| OI
    G5 -->|"Signal reference ground"| OI

    classDef ac fill:#f8d7da,stroke:#8b2635,color:#111;
    classDef v24 fill:#fff1bd,stroke:#9b6b00,color:#111;
    classDef v5 fill:#d9f5df,stroke:#287a3e,color:#111;
    classDef control fill:#dcecff,stroke:#2d62a8,color:#111;
    classDef led fill:#eee1ff,stroke:#7345a3,color:#111;
    classDef protection fill:#ffe2c2,stroke:#a34e00,color:#111;

    class AC,PS1 ac;
    class J1,W1P,W1N,X1,U1 v24;
    class P5,G5,C1,CTL5,C2 v5;
    class ESP,U2P,U2C,U2D,R1,R2 control;
    class OI,OO,II,IO led;
    class F1,F2,F3 protection;

Critical points:

• Fuses go in positive conductors only.
• All four strip ends receive parallel 5 V/GND injection.
• Only clock/data are serial: ESP32 → outer → inner.
• Leave the inner strip’s final CO/DO unconnected.
• All ESP32, shifter and LED grounds share the local GND BUS.
• Disconnect external 5V/VIN power before connecting the ESP32’s programming USB cable.

For a 30-foot direct-5 V run, use 4 AWG pure-copper cable if you want the full 7 A capability. 6 AWG is the bare minimum for the long cable alone, but your power brick’s thin output cord and every connector add further loss.

Wire calculation

Thirty feet away means 60 conductor-feet: 30 ft positive plus 30 ft return.

\[ V_{\text{drop}}=I \times R_{\text{wire}} \times 60/1000 \]

Using stranded-copper resistance at 25°C from Southwire’s conductor data:

Those voltages exclude the brick’s factory cable, fuses, splices, and connectors. That is why I’d use 4 AWG for a genuine 7 A design.

Alternatives:

• 6 AWG: reduce the firmware LED limit to about 5 A.
• 8 AWG: reduce it to about 4–4.5 A.
• Use flexible, stranded, pure-copper welding/battery cable—one red and one black conductor. Do not buy CCA cable.

Complete direct-5 V power circuit

flowchart TB
    AC["120 V AC outlet"] --> PS["Existing regulated 5 V / 10 A power brick"]

    PS -->|"+5 V"| F1["F1 — 10 A main fuse<br/>as close to supply as practical"]
    PS -->|"GND"| TN["Covered negative splice"]

    F1 --> TP["Covered positive splice"]
    TP --> WP["30 ft RED<br/>4 AWG stranded pure copper"]
    TN --> WN["30 ft BLACK<br/>4 AWG stranded pure copper"]

    WP --> XP["High-current disconnect<br/>Anderson SB50 or equivalent<br/>must explicitly accept 4 AWG"]
    WN --> XN["Matching negative contact"]

    XP --> P5["Local +5 V distribution block<br/>must accept 4 AWG"]
    XN --> G5["Local GND distribution block<br/>must accept 4 AWG"]

    P5 --> F2["F2 — 7.5 A LED fuse"]
    F2 --> LP["+5 V LED bus"]

    P5 --> F3["F3 — 1 A controller fuse"]
    F3 --> CP["+5 V controller bus"]

    LP --- C1["C1 — 1000 µF, ≥10 V<br/>observe polarity"] --- G5

    LP --> OI["Outer strip input-end +5 V"]
    G5 --> OIG["Outer strip input-end GND"]

    LP --> OO["Outer strip output-end +5 V"]
    G5 --> OOG["Outer strip output-end GND"]

    LP --> II["Inner strip input-end +5 V"]
    G5 --> IIG["Inner strip input-end GND"]

    LP --> IO["Inner strip output-end +5 V"]
    G5 --> IOG["Inner strip output-end GND"]

    OI --> OS["Outer strip — 299 LEDs"]
    OIG --> OS
    OO --> OS
    OOG --> OS

    II --> IS["Inner strip — 284 LEDs"]
    IIG --> IS
    IO --> IS
    IOG --> IS

    CP --> CTRL["ESP32 + 74AHCT125 controller circuit"]
    G5 --> CTRL

All four strip power-injection branches are parallel. Use short 18 AWG wires from the local distribution blocks to the LED strip pads. Power is never routed through the first strip to supply the second one.

ESP32, level shifter, and data circuit

flowchart LR
    CP["+5 V from F3"] --> ESP["ESP32 5V/VIN"]
    GND["Local GND block"] --> ESPG["ESP32 GND"]

    CP --> VCC["74AHCT125 pin 14 — VCC"]
    GND --> UG["74AHCT125 pin 7 — GND"]
    VCC --- C2["C2 — 0.1 µF ceramic<br/>physically beside pins 14 and 7"] --- UG

    GND --> OE1["Pins 1 and 4 — /OE<br/>tie LOW to enable channels 1 and 2"]

    ESP18["ESP32 GPIO18 — clock"] --> A1["Pin 2 — 1A"]
    A1 --> Y1["Pin 3 — 1Y"]
    Y1 --> RC["330 Ω resistor"]
    RC --> OCI["Outer strip CI"]

    ESP23["ESP32 GPIO23 — data"] --> A2["Pin 5 — 2A"]
    A2 --> Y2["Pin 6 — 2Y"]
    Y2 --> RD["330 Ω resistor"]
    RD --> ODI["Outer strip DI"]

    OCO["Outer strip CO"] --> ICI["Inner strip CI"]
    ODO["Outer strip DO"] --> IDI["Inner strip DI"]

    CP --> UNUSED_OE["Pins 10 and 13 — unused /OE<br/>tie HIGH"]
    GND --> UNUSED_IN["Pins 9 and 12 — unused inputs<br/>tie LOW"]
    UNUSED_OUT["Pins 8 and 11 — unused outputs"] --> NC["No connection"]

Important construction details:

• The barrel connector and little barrel-to-screw adapter cannot remain in the 7 A path.
• With the brick unplugged, cut off the low-voltage barrel plug, shorten the brick’s thin DC cord as much as practical, and verify polarity with a multimeter before connecting it.
• Do not open the AC/DC brick.
• Use crimped high-current splices, ring terminals, and covered distribution blocks designed for 4 AWG. Ordinary Wago connectors and Dupont wires cannot accept this cable.
• The power brick stays near the outlet. Only the two-conductor DC cable travels to the hanging piece.
• After assembly, test at reduced brightness and measure the local bus while displaying full white. Aim for at least approximately 4.75 V at the sculpture under maximum configured load.
• Do not power the ESP32 simultaneously from this circuit and USB unless the particular board explicitly supports isolated or protected dual powering.