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Refactor README to remove level shifter references and clarify LED data connection #6

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colinmakerofthings merged 1 commit into from
Feb 25, 2026
Merged

Refactor README to remove level shifter references and clarify LED data connection #6

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20 changes: 4 additions & 16 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
PixelBrain32 is a personal ESP32-based controller for addressable LED strips, designed for use with ESPHome and Home Assistant.

It's a small custom PCB that powers an ESP32 from the same 5 V supply as the LEDs, provides proper signal conditioning
and level shifting for WS2812-style strips, and exposes a physical button for local control.
for WS2812-style strips, and exposes a physical button for local control.

---

Expand All @@ -16,7 +16,6 @@ and level shifting for WS2812-style strips, and exposes a physical button for lo
- Designed for WS2812B / NeoPixel-compatible LEDs
- Proper LED data conditioning:
- Series resistor
- 5 V level shifter (74AHCT125)
- Bulk power smoothing capacitor for LED inrush current
- Two physical push buttons for local control:
- SW1 (GPIO33): toggle on/off
Expand All @@ -32,7 +31,7 @@ and level shifting for WS2812-style strips, and exposes a physical button for lo
|-------------|----------------------------------|
| MCU | ESP32 DevKit (plug-in headers) |
| LED Power | External 5 V PSU |
| LED Data | 3.3 V → 5 V level-shifted |
| LED Data | 3.3 V direct drive |
| Control | ESPHome + Home Assistant |
| Form factor | Custom PCB |

Expand Down Expand Up @@ -80,16 +79,7 @@ PixelBrain32 exists because:
│
├───────────────────────────> ESP32 VIN (+5V)
│
74AHCT125
┌──────────────┐
+5V ───────>│ VCC │
GND ───────>│ GND │
GND ───────>│ /OE (pin 1) │
│ │
ESP32 GPIO ──[330Ω]──> IN (pin 2)│
│ OUT (pin 3) ├──────────────────> LED DATA (screw terminal)
└──────────────┘
(100 nF bypass cap on VCC–GND, placed close to IC)
ESP32 GPIO ──[330Ω]────────────────────────────────> LED DATA (screw terminal)

Push Button SW1 (Toggle on/off):
+3.3V (internal pull-up via INPUT_PULLUP)
Expand Down Expand Up @@ -120,11 +110,9 @@ ESP32 GPIO32 ─────────────────┤
| J2 | Screw terminal (2P) | — | LED +5V and GND output |
| J3 | Screw terminal (1P) | — | LED DATA output |
| C1 | Electrolytic cap | 1000 µF, 10 V | Bulk smoothing, near LED terminal |
| C2 | Ceramic cap | 100 nF | 74AHCT125 VCC bypass, place close to IC |
| C3 | Ceramic cap | 100 nF | Across SW1 button terminals (debounce) |
| C4 | Ceramic cap | 100 nF | Across SW2 button terminals (debounce) |
| R1 | Resistor | 330 Ω | Series data resistor, ESP32 → level shifter|
| U1 | Level shifter | 74AHCT125 | 3.3 V → 5 V data signal conversion |
| R1 | Resistor | 330 Ω | Series data resistor, ESP32 → LED data |
| SW1 | Push button | Tactile / momentary | GPIO33, INPUT_PULLUP — toggle on/off |
| SW2 | Push button | Tactile / momentary | GPIO32, INPUT_PULLUP — brightness control |
| U2 | MCU | ESP32 DevKit | Socketed on pin headers |
Expand Down