Instruction file imported from tamaygz/esp-wled-projects (.github/instructions/hardware.instructions.md). Copyright stays with the author.

Hardware — Instructions

Level Shifting (Critical)

ESP32 GPIO outputs are 3.3 V logic. LED strips (SK6812, WS2812B) require a 5 V data signal. Always place a level shifter on every LED data line.

• Preferred ICs: SN74HCT245 (octal) or 74AHCT125 (quad buffer)
• One gate per data channel
• OE pin active-low — tie to GND to keep buffers always enabled
• Bypass caps: 100 nF ceramic close to each VCC pin

Power Injection

For LED strips longer than 1 m (or >50 LEDs):

• Inject power at both ends of the strip
• Inject every ≤ 50 LEDs for runs >2 m
• Wire gauge: 22 AWG minimum for ≤1 A; 18 AWG for >1 A per run

Current Budget Formula

I_total = N_leds × mA_per_channel × channels

• SK6812 RGBW: use 20 mA per channel, 4 channels → 80 mA/LED maximum
• WS2812B RGB: use 20 mA per channel, 3 channels → 60 mA/LED maximum
• Apply a 20 % safety headroom when selecting PSU wattage
• Add 10 % derating for continuous operation

Example (SK6812, 60 LEDs): 60 × 20 mA × 4 = 4.8 A peak → PSU ≥ 6 A (with headroom)

bom.md Format

hardware/bom/bom.md must include:

1. Power budget table (LED current calculation, headroom, PSU selection)
2. Parts list table with columns: Part, Qty, Unit Price, Supplier, Part No., Notes
3. Total cost estimate

Preferred suppliers: LCSC (PCB components), Aliexpress / BTF-Lighting (LED strips), Mouser / DigiKey (precision parts).

Common GND

The PSU 5 V GND and the ESP32 GND must share a common ground. This is not automatic — wire it explicitly between the PSU terminal block and the ESP32 GND pin.

KiCad Conventions

• Schematic sources: hardware/pcb/*.kicad_sch
• PCB source: hardware/pcb/*.kicad_pcb
• Gerber exports: hardware/pcb/gerbers/
• Export Gerbers before every board order; commit them alongside the source

GPIO Assignment (WLED defaults — override in cfg.json or via build flag)

Avoid: GPIO 0 (boot mode), GPIO 2 (boot LED), GPIO 12 (boot flash voltage), GPIO 15 (boot messages).