N A O D E C
WS2815 Single Strip Controller · LED Strip Test Kit · Rev 1.0
ESP32-S3 DevKitC-1 · SN74AHCT125N · 336 LEDs · 12VDC · WLED
12V
5V
GND
3.3V
DATA 5V
BACKUP BI
⚠ AVOID GPIO 0,3,45,46
Strapping pins — boot conflict
LED CONTROLLER + LEVEL SHIFTER
ESP32-S3
DevKitC-1
N16R8 · 16MB · 8MB PSRAM
WLED Firmware
GPIO16
Vin 5V
GND
UART
USB-C
SN74AHCT125N
U1 · Level Shifter
3.3V → 5V Logic
14-pin DIP (IC socket)
1OE (1)
1A (2)
1Y (3)
GND (7)
VCC (14)
Gates 2–4: OE→VCC, A→GND, Y=N/C
C2
100nF
OE→Vcc
A→GND
CH1 · 3.3V
CH1 · 5V BUFFERED OUTPUT
R1 47Ω
STRIP 1 — WS2815 · 336 LEDs · 12VDC
WS2815 × 336
12VDC · 6A max · WLED Out 1
GPIO16 → U1 → R1 47Ω → DI · 16AWG / 18AWG
+12V
DI
BI
GND
+12V
DO
BO
GND
POWER SOURCE — LOGIC
PSU 5V 2A
10W · Logic Power
+5V
GND
+5V RAIL
PSU 12V 8A+
96W+ · LED Power Rail
⚡ ISOLATED
+12V
GND
FILTER
C1 1000µF
PSU5V/MCU
U1
C2+spare
STRIP
PSU12V
⚠ NEVER CONNECT V+ RAILS TOGETHER ⚠
5V · 12V — keep positive rails isolated
── COMMON GROUND BUS ──
SIGNAL FLOW & WIRING SIZING
SIGNAL FLOW
CH
GPIO
Buffer Path
R
LEDs
AWG
1
GPIO16
U1: 1A(2) → 1Y(3)
47Ω
336
18
POWER DISTRIBUTION
PSU 5V 2A → ESP32 Vin, U1 VCC (pin 14)
PSU 12V 8A+ → C1 1000µF → Strip +12V
1OE (pin 1) → GND (always enabled)
Spare gates: OE→Vcc, A→GND, Y=N/C
POWER CALCULATIONS
Strip
LEDs
Current
PSU
Wire
WS2815
336
~6.05A full white
12V 8A+
16AWG
Logic
—
~0.5A (ESP32+U1)
5V 2A
22AWG
TOTAL
336
~6.55A combined
⚠ WS2815 ~10–15mA/pixel @ 12V
⚠ Not 60mA like WS2812B @ 5V
WIRE GAUGES (AWG)
12V Power:
16 AWG min (6A)
Data line:
22–18 AWG (<2m)
GND:
16 AWG minimum
BILL OF MATERIALS & GPIO MAPPING
BILL OF MATERIALS
REF
COMPONENT
VALUE / DESCRIPTION
MCU
ESP32-S3-DevKitC-1
N16R8, WLED, WiFi+BLE
U1
SN74AHCT125N
14-pin DIP, 3.3V→5V
—
14-pin DIP IC Socket
Quick-release for U1
R1
Resistor
47Ω ¼W Metal Film
C1
Electrolytic Cap
1000µF 25V, 12V rail
C2
Ceramic Cap
100nF, U1 VCC decoupling
LED
WS2815 12V
336 LEDs total
PSU1
Power Supply 5V 2A
10W, ESP32 + U1
PSU2
Power Supply 12V 8A+
96W+, WS2815 strip
GPIO MAPPING
GPIO
Buffer
Channel
Strip
LEDs
Type
GPIO16
U1 CH1
CH1
#1
336
WS2815
WLED CONFIGURATION
GPIO
LED Count
Type
Voltage
GPIO16
336
WS281x
12V
ENGINEERING NOTES & REVISION HISTORY
ENGINEERING NOTES
1.
Common GND — both PSU negatives tied.
2.
VCC (pin 14) = 5V sets output HIGH.
3.
1OE → GND (enabled).
4.
Spare 2OE+3OE+4OE → Vcc (disabled).
5.
Spare inputs → GND, outputs N/C.
6.
R1 47Ω — signal reflection protection.
7.
C1 1000µF — inrush protection at strip.
8.
C2 100nF close to U1 VCC — latch-up.
9.
WS2815 BI via dashed backup line.
10.
GPIO 0,3,45,46 / 35–37 / 19–20 avoided.
11.
WLED: 1 output segment in LED Prefs.
12.
Power injection if strip run >5m.
13.
~6.05A max (336 × ~18mA @ 12V).
14.
Use 14-pin DIP socket for U1.
REVISION HISTORY
Rev 1.0
— Initial release.
Single strip, LED Strip Test Kit.
336 × WS2815 · ESP32-S3 · SN74AHCT125N.
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