sideline/klubhaus-doorbell-hardware.md

# Klubhaus Doorbell — Hardware Spec Sheet

Derived from source code analysis of [klubhaus-doorbell](https://git.notsosm.art/david/klubhaus-doorbell.git) and manufacturer datasheets.

The project targets **three** ESP32-based development boards, each with an integrated TFT display and touch input. All three are all-in-one "ESP32 + screen" modules (not a bare Arduino with a separate breakout).

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## Board 1 — ESP32-32E (2.8″ ILI9341)

| Attribute | Value |
|---|---|
| **Manufacturer** | Hosyond (likely) |
| **Module** | ESP32-32E (ESP32-WROOM-32 family) |
| **SoC** | ESP32-D0WD-V3, Xtensa dual-core 32-bit LX6 |
| **Max clock** | 240 MHz |
| **SRAM** | 520 KB |
| **ROM** | 448 KB |
| **Flash** | 4 MB (external QSPI) — per FQBN `FlashSize=4M` |
| **PSRAM** | Flagged in build (`-DBOARD_HAS_PSRAM`) — likely present but unconfirmed capacity |
| **WiFi** | 2.4 GHz 802.11 b/g/n |
| **Bluetooth** | v4.2 BR/EDR + BLE |
| **Display driver** | ILI9341 |
| **Display size** | ~2.8″ (inferred from `.crushmemory` note "original 2.8″ ILI9341") |
| **Resolution** | 320 × 240 (landscape rotation 1) |
| **Display interface** | 4-line SPI |
| **Color depth** | 65K (RGB565) |
| **Touch** | XPT2046 resistive (SPI) |
| **Backlight GPIO** | 22 |
| **SPI pins** | MOSI 23, SCLK 18, CS 5, DC 27, RST 33 |
| **Touch CS** | GPIO 14 |
| **SPI clock** | 40 MHz (display), 20 MHz (read), 2.5 MHz (touch) |
| **Serial baud** | 115200 |
| **USB** | Type-C (programming / power) |
| **Display library** | TFT_eSPI (vendored) |

---

## Board 2 — ESP32-32E-4″ (Hosyond 4.0″ ST7796)

| Attribute | Value |
|---|---|
| **Manufacturer** | Hosyond |
| **Module** | ESP32-32E |
| **SoC** | ESP32-D0WD-V3, Xtensa dual-core 32-bit LX6 |
| **Max clock** | 240 MHz |
| **SRAM** | 520 KB |
| **ROM** | 448 KB |
| **Flash** | 4 MB (external QSPI) — per FQBN `FlashSize=4M` |
| **PSRAM** | Flagged in build (`-DBOARD_HAS_PSRAM`) — likely present but unconfirmed capacity |
| **WiFi** | 2.4 GHz 802.11 b/g/n |
| **Bluetooth** | v4.2 BR/EDR + BLE |
| **Display driver** | ST7796S |
| **Display size** | 4.0″ |
| **Resolution** | 320 × 480 (landscape rotation 1) |
| **Display interface** | 4-line SPI |
| **Color depth** | 262K (RGB666) per manufacturer; firmware uses RGB565 |
| **Touch** | XPT2046 resistive (SPI) |
| **Backlight GPIO** | 27 (active HIGH) |
| **SPI pins** | MISO 12, MOSI 13, SCLK 14, CS 15, DC 2, RST tied to EN |
| **Touch CS / IRQ** | GPIO 33 / GPIO 36 |
| **SPI clock** | 40 MHz (display), 20 MHz (read), 2.5 MHz (touch) |
| **Serial baud** | 115200 |
| **Physical size** | 60.88 × 111.11 × 5.65 mm |
| **USB** | Type-C |
| **Display library** | TFT_eSPI (vendored) |
| **Reference** | [lcdwiki.com/4.0inch_ESP32-32E_Display](https://www.lcdwiki.com/4.0inch_ESP32-32E_Display) |

---

## Board 3 — Waveshare ESP32-S3-Touch-LCD-4.3

| Attribute | Value |
|---|---|
| **Manufacturer** | Waveshare |
| **Module** | ESP32-S3-WROOM-1-N16R8 |
| **SoC** | ESP32-S3, Xtensa dual-core 32-bit LX7 |
| **Max clock** | 240 MHz |
| **SRAM** | 512 KB |
| **ROM** | 384 KB |
| **PSRAM** | 8 MB (onboard) |
| **Flash** | 16 MB — per FQBN `FlashSize=16M` |
| **WiFi** | 2.4 GHz 802.11 b/g/n |
| **Bluetooth** | v5.0 BLE |
| **Antenna** | Onboard PCB antenna |
| **Display driver** | RGB parallel (16-bit, 5-6-5 R/G/B channel split) |
| **Display size** | 4.3″ |
| **Resolution** | 800 × 480 |
| **Color depth** | 65K |
| **Touch** | GT911 capacitive, 5-point, I2C |
| **Touch I2C** | SDA 8, SCL 9, INT 4, addr 0x14 (runtime) / 0x5D (defined in config) |
| **I/O expander** | CH422G (I2C, shared bus with touch) — controls backlight, LCD reset, SD CS, etc. |
| **Pixel clock** | 14 MHz (LovyanGFX Bus_RGB) |
| **USB** | Type-C (UART via CH343P + native USB HW CDC on GPIO 19/20) |
| **Peripheral interfaces** | CAN, RS485, I2C, UART, TF card slot (SPI via CH422G EXIO4), ADC sensor header |
| **Partition scheme** | `app3M_fat9M_16MB` (3 MB app, 9 MB FAT) |
| **Serial baud** | 115200 |
| **Display library** | LovyanGFX (vendored) |
| **Reference** | [waveshare.com/wiki/ESP32-S3-Touch-LCD-4.3](https://www.waveshare.com/wiki/ESP32-S3-Touch-LCD-4.3) |

### RGB bus pin map (Board 3)

| Signal | GPIOs |
|---|---|
| Red R0–R4 | 1, 2, 42, 41, 40 |
| Green G0–G5 | 39, 0, 45, 48, 47, 21 |
| Blue B0–B4 | 14, 38, 18, 17, 10 |
| DE / VSYNC / HSYNC / PCLK | 5, 3, 46, 7 |

---

## Known unknowns

These are facts the code references or implies but does not pin down:

- **PSRAM size on Boards 1 & 2.** The build flag `-DBOARD_HAS_PSRAM` is set for both ESP32-32E targets, but the capacity (typically 4 MB or 8 MB on ESP32-WROOM-32 variants) is never stated in the code or config. Hosyond product pages list some models with PSRAM and some without.
- **Exact screen panel size for Board 1.** The `.crushmemory` file calls it "original 2.8″ ILI9341," but the ILI9341 driver is also used on 2.4″ and 3.2″ panels. No board_config.h comment names the panel size explicitly.
- **Board 1 manufacturer.** The code doesn't name Hosyond for the 2.8″ board the way it does for the 4″. It could be a generic ESP32-32E devkit from any number of vendors.
- **Board 1 SPI MISO pin.** Not defined in `tft_user_setup.h` (only MOSI/SCLK/CS/DC/RST are set). This means SPI read-back from the display may not be wired or used.
- **Serial port path.** All three `board-config.sh` files default to `/dev/ttyUSB0`, which is a Linux convention. The actual development machine appears to be macOS, so the real port (e.g. `/dev/cu.usbserial-*`) is likely overridden at runtime.
- **GT911 I2C address discrepancy (Board 3).** `board_config.h` defines `GT911_ADDR 0x5D` but `LovyanPins.h` configures the touch at address `0x14`. Both are valid GT911 addresses; the runtime address depends on the INT pin state at boot. The code comment says "IMPORTANT: Address 0x14, not 0x5D!" suggesting 0x5D was tried and didn't work.
- **CH422G expander pin mapping (Board 3).** `LovyanPins.h` defines symbolic names (`TP_RST=1`, `LCD_BL=2`, `LCD_RST=3`, `SD_CS=4`, `USB_SEL=5`) but these are CH422G *expander output indices*, not ESP32 GPIOs. The I2C init sequence that drives these pins lives in `DisplayDriverGFX.cpp`, which was not fully inspected.

## Unknown unknowns

Things that are plausibly relevant but entirely absent from the codebase:

- **Power supply specs.** No code references input voltage ranges, regulators, or battery charging circuits, though the Waveshare board has a PH2.0 LiPo header and the Hosyond boards support external lithium batteries with onboard charge management.
- **Thermal limits / operating temperature range.** Not mentioned anywhere.
- **Hardware revision / PCB version.** No version identifiers for any of the three physical boards.
- **Antenna characteristics.** The Waveshare board uses an onboard PCB antenna; the Hosyond boards likely do as well. Gain, radiation pattern, and any shielding considerations are unaddressed.
- **Display viewing angle / brightness / contrast.** The Hosyond 4″ is listed as TN type (narrower viewing angles); the Waveshare 4.3″ is likely IPS but not confirmed in code.
- **ESD / EMC compliance.** No mention of certifications (FCC, CE, etc.).
- **Deep sleep / low-power modes.** The firmware uses `millis()`-based timing and a display-off state, but never enters ESP32 deep sleep. Whether the hardware supports wake-on-touch or wake-on-WiFi is not explored.
- **Audio hardware.** The Hosyond boards support external speakers per their datasheets, and the codebase has no audio code. The Waveshare board does not appear to have onboard audio.
- **SD card.** The Waveshare board has a TF card slot (CS via CH422G EXIO4), and the Hosyond boards have TF card slots as well. The firmware does not use storage.