Devesh36/usb-c-phone-stand-light

README.md

# Desk Glow — USB-C Magnetic Charging Stand

A rounded phone stand with a ribbed back, central rear support, magnetic Qi
charging face, and two LED emitters in the base. USB-C is the sole power
input. The base PCB distributes power; the LEDs live on a separate indicator
board mounted underneath the front lenses.

## LED channels

| Part | Channel |
| --- | --- |
| C540985 / HL-C3535F3V3EA-ZW | UV emitter powered from the USB supply through 1 kΩ. |
| C540986 / HL-C3535F4IR3EA-ZW | IR emitter driven by the Qi power-transfer signal through 470 Ω. |

Both imported footprints use `<silkscreenrect>` and are placed with
`pcbRotation={45}`. These are UV/IR emitters, not visible red/green status
indicators. The assembly shows neutral, unpowered windows. Optical output and
window transmission are not validated; this revision is for PCB layout evaluation.

## Power and signal connections

```text
USB-C adapter (5 V / 3 A)
  → Adafruit HUSB238 module configured for 5 V / 3 A
  → POWER PCB J_USB
      ├─ F_QI (2 A) → J_QI → micro-USB pigtail → Qi transmitter → matched coil
      └─ F_LED (250 mA) → R_UV (1 kΩ) → UV LED

Qi transmitter LED_A → J_STATUS → R_IR (470 Ω) → IR LED
All signal returns connect to GND.
```

The POWER PCB uses soldered wire pads instead of tall screw terminals, allowing
3 mm PCB supports and the thinner base. Add strain relief to each soldered lead.

The assembly includes separate positive and ground supply wires, the transmitter
power lead, the controller-to-coil pair, the charging-status return cable, and the
four-conductor indicator cable. Copper on the POWER PCB joins the USB input to
the fused charging output. The positive charging traces are 1 mm wide and the
bottom copper plane provides the ground return.

| Connector | Pin mapping |
| --- | --- |
| POWER.J_USB | 1 = +5 V from HUSB238; 2 = GND |
| POWER.J_QI | 1 = fused +5 V; 2 = GND; wire to micro-USB VBUS/GND |
| POWER.J_STATUS | 1 = transmitter LED_A; 2 = transmitter signal GND |
| POWER.J_PANEL → INDICATORS.J_LEDS | 1 = UV anode; 2 = UV cathode; 3 = IR anode; 4 = IR cathode; connect straight through |

Use 22 AWG for power pairs and insulated 28 AWG for indicator/status wires.
Preserve the transmitter's matched coil and short factory coil leads. Connect
the coil only to its transmitter output. Set and measure the HUSB238 output at
5 V before plugging in the charging electronics.

## Charging controller and status configuration

This revision uses the **Seeed Qi Wireless Charger Transmitter v1.0**, based on
BQ500211, with its matched coil. Its published Eagle PCB outline is approximately
68.58 × 54.61 mm. The assembly reserves space for that board rather than the
previous Adafruit 2162 module, which lacks a documented external status interface.

Set the transmitter's **R8 (LED_MODE) to 64.9 kΩ, 1%**, selecting BQ500211 LED mode
4. This makes LED1 green steady during power transfer and off in standby, charge
complete, or fault. Bring **U1 pin 7 / LED_A** out from the **U1-connected pad of
R3** (the optional unpopulated resistor footprint), and bring signal GND to
POWER.J_STATUS. Confirm continuity to U1 pin 7 with power off. Keep R3 unpopulated;
use its pad as a signal connection. Do not use the board's buzzer-driven D1 as
this status signal. No firmware is required.

The LED channels retain current-limiting resistors of 1 kΩ (UV) and 470 Ω (IR).
They are low-current channels, not high-power LED drivers. The C540985 pin aliases
are corrected to match the footprint's + mark: pad 1 is anode, pad 2 cathode.
Its center pad is left isolated. C540986 uses A1 and C; its center A2 pad is left
unrouted. Verify supplier pinout and thermal-pad requirements before fabrication.

Sources: [Seeed transmitter and design files](https://wiki.seeedstudio.com/Qi_Wireless_Charger_Transmitter/),
[TI BQ500211 datasheet, LED indication modes](https://www.ti.com/lit/ds/symlink/bq500211.pdf),
[HUSB238 USB-C module](https://www.adafruit.com/product/5807).

The wireless stage is a 5 W Qi design. A 58 mm OD / 48 mm ID magnetic ring gives
MagSafe-style alignment; this is not a certified MagSafe fast-charging design.
Use the matched transmitter coil/ferrite assembly and check its delivered size
against the nominal 53 × 53 × 4 mm coil envelope before printing.

## Stand assembly

The base is 92 × 110 mm and only **14 mm high**, including its removable lid.
The main back housing is **14 mm thick** before the charging face and support
joint, reduced from 20 mm. The base was previously 22 mm high. The rounded backrest leans 20° from
vertical and supports the phone on two cradle lips. Its ribbed rear cover encloses
the charger and wiring, with a central rounded support down to the base. The
support is fixed at this angle; the reference's folding mechanism is not modeled.
A single flush USB-C socket is exposed at the **left edge of the base**,
inside a black rounded surround. Its enlarged opening clears a typical
12 × 6 mm cable overmold. Two separate neutral
windows sit in the front of the lid, above the indicator board.

The nominal phone envelope is 78 × 165 × 9 mm. Adjust `dock.chargerHeight` for the
actual receiver-coil position and verify that the case fits the cradle. Printed
parts use PETG; print the USB surround in black and the windows in translucent material. Dry-fit components
and provide strain relief at the base cable opening. Retain the controller on its
rear-cover supports with electronics-grade adhesive pads; secure the indicator
board under the lid and fit the lenses. Use nonconductive tape at the ferrite
corners to retain the coil against the front charging face.

Use four M3 × 12 mm screws for the backrest, two M3 × 12 mm screws for the rear
support foot, two low-profile M3 × 12 mm charging-cover screws, four M2 × 6 mm lid
screws, and four M2 × 4 mm PCB screws. Add four rubber feet. Dimensions of supplier
components are assembly envelopes; verify the actual module revision and fit.

## Project files

- `index.circuit.tsx`: full native TSCircuit assembly and the POWER PCB.
- `indicators.circuit.tsx`: separate UV/IR emitter PCB.
- `stand-mechanics.tsx`: printable housing, backrest, support, and lenses.
- `charger-models.ts`: component envelopes and the connected wiring harnesses.
- `mechanical/`: printable STLs and dimensions.
- `desk-glow-stand-project.zip`: source and printable parts together.

TSCircuit currently supports one board anchoring each connected printed-part
assembly. The indicator circuit is therefore exported separately and represented
by its matching placed model in the full assembly.

## Verification

Both PCB circuits are built and checked digitally. The stand is also checked for
phone clearance, enclosure fit and wiring clearance, and each printable solid is
exported to STL. Real charging, status timing, temperature, magnetic retention,
and phone/case fit still require testing on a physical prototype.

```sh
bun install
bun run export:stl
tsci build --disable-parts-engine
tsci dev
```