colmarius · colmarius · Feb 11, 2026 · Feb 11, 2026 · Feb 11, 2026 · Feb 11, 2026
diff --git a/.agents/plans/in-progress/004-support-display-fs-v1-3-5-inch.md b/.agents/plans/in-progress/004-support-display-fs-v1-3-5-inch.md
@@ -0,0 +1,49 @@
+# Plan: Support Display FS V1 (3.5 inch)
+
+Status: IN-PROGRESS
+
+## Goal
+
+Add first-class support for the 3.5-inch Display FS V1 in the CLI, including detection, resolution handling, protocol parity, and documentation, while keeping the 0.96-inch flow intact.
+
+## Tasks
+
+- [ ] **Task 1: Model detection + config baseline**
+  - Scope: `src/port.rs`, `src/protocol.rs`, `src/main.rs`
+  - Depends on: none
+  - Acceptance:
+    - CLI can identify which display type is connected (0.96 vs 3.5) using VID/PID or port description
+    - A single configuration struct holds model-specific defaults (resolution, baud rate, orientation)
+  - Notes: Add a `DisplayModel` enum and extend detection to use port description hints ("AB"/"AD") in addition to VID/PID.
+
+- [ ] **Task 2: Protocol parity for 3.5-inch commands**
+  - Scope: `src/protocol.rs`
+  - Depends on: Task 1
+  - Acceptance:
+    - Implement read/write helpers for WHO_AM_I, brightness, and unconnect settings
+    - Add humiture report command handling (enable/read) with a typed response
+  - Notes: Align command bytes with WeAct protocol v1.1 and keep them model-agnostic where possible.
+
+- [ ] **Task 3: Image pipeline for large display**
+  - Scope: `src/image.rs`, `src/text.rs`, `src/protocol.rs`
+  - Depends on: Task 1
+  - Acceptance:
+    - Rendering handles 320x480 and 480x320 orientations without clipping
+    - Bitmap writes support chunked writes sized for the active model
+  - Notes: Consider optional FastLZ support as follow-up if performance is inadequate.
+
+- [ ] **Task 4: CLI options + UX updates**
+  - Scope: `src/main.rs`, `README.md`, `site/index.html`, `site/styles.css`
+  - Depends on: Task 1
+  - Acceptance:
+    - CLI flags allow forcing a model and baud rate override
+    - Help text documents the 3.5-inch usage and sensor availability
+  - Notes: Keep defaults auto-detect; only require manual selection when detection is ambiguous.
+
+- [ ] **Task 5: Tests + docs refresh**
+  - Scope: `src/port.rs`, `README.md`, `AGENTS.md`, `.agents/research/weact-display-fs-v1-3-5-research.md`
+  - Depends on: Task 2
+  - Acceptance:
+    - Unit tests cover model detection paths and protocol command enums
+    - Documentation clearly describes both devices and the plan forward
+  - Notes: Update plan status to COMPLETED once verification passes.
diff --git a/.agents/research/weact-display-fs-v1-3-5-research.md b/.agents/research/weact-display-fs-v1-3-5-research.md
@@ -0,0 +1,118 @@
+# Research: WeAct Display FS V1 (3.5 inch)
+
+**Date:** 2026-02-11
+**Status:** Complete
+**Tags:** display-fs, weact, usb-cdc, protocol, rust, python
+
+## Summary
+
+The 3.5-inch Display FS V1 is a USB 2.0 Full Speed CDC device with a 320x480 RGB565 IPS LCD and on-board humidity/temperature sensor. WeAct publishes a Python System Monitor app (forked from Turing Smart Screen) with protocol and implementation details, and a SourceForge protocol spreadsheet describing the full command set (write/read/auto-report). The display shares the same command protocol as the 0.96-inch version, but differs in resolution, baud rate (1,152,000 in reference code), and adds a humiture auto-report command.
+
+## Key Learnings
+
+- Official WeAct docs list the 3.5" model as 320x480 RGB565 with USB2.0 FS (CDC) and a humidity/temperature sensor; the 0.96" is 80x160 RGB565 with no sensor.
+- Reference Python code auto-detects the device by scanning the port description for "AB" (3.5") and "AD" (0.96") and sets the resolution accordingly.
+- The reference Python app opens the serial port at **1,152,000 baud** for both devices.
+- The WeAct protocol spreadsheet defines command bytes, packet lengths, read responses, and humiture auto-report format.
+- Image transfer supports raw RGB565 payloads or a FastLZ-compressed variant (4k chunking) with 500ms timeout per chunk.
+
+## Details
+
+### Hardware Specs (WeAct Studio)
+
+From WeAct Studio System Monitor README / SourceForge:
+
+- **Display FS V1 (3.5 inch)**
+  - Resolution: **320 x 480** RGB565
+  - Communication: **USB2.0 FS (CDC)**
+  - Sensor: **Humidity + Temperature**
+  - Size: **58.5mm x 87.7mm x 9.0mm**
+- **Display FS V1 (0.96 inch)**
+  - Resolution: **80 x 160** RGB565
+  - Communication: **USB2.0 FS (CDC)**
+  - Sensor: **None**
+  - Size: **43mm x 14.5mm**
+
+### Device Detection (Python reference)
+
+From `weact_device_setting.py` in WeActStudio.SystemMonitor:
+
+- Auto-detects ports by scanning the port description for:
+  - `"AB"` → 3.5-inch device (type 0)
+  - `"AD"` → 0.96-inch device (type 1)
+- Sets dimensions based on type:
+  - Type 0: 320x480 (portrait), 480x320 (landscape)
+  - Type 1: 80x160 (portrait), 160x80 (landscape)
+- Opens serial port at **1,152,000 baud**, 8N1, 200ms timeout.
+
+### Protocol (SourceForge XLSX v1.1)
+
+Source: `WeAct Studio Display Communication protocol_v1.1.xlsx` (Doc folder on SourceForge).
+
+**Write commands** (all packets end with `0x0A`):
+
+- `0x02 SET_ORIENTATION` (len 3): `0x02, x, 0x0A` where `x=0-4`
+- `0x03 SET_BRIGHTNESS` (len 5): `0x03, x, y_l8, y_h8, 0x0A`
+  - `x = brightness (0-255)`
+  - `y = brightness time (0-5000 ms)`
+- `0x04 FULL` (len 12): `0x04, xs_l8, xs_h8, ys_l8, ys_h8, xe_l8, xe_h8, ye_l8, ye_h8, c_l8, c_h8, 0x0A`
+- `0x05 SET_BITMAP` (len 10): `0x05, xs_l8, xs_h8, ys_l8, ys_h8, xe_l8, xe_h8, ye_l8, ye_h8, 0x0A`
+  - Image data (RGB565) follows immediately. Timeout 500ms.
+- `0x06 ENABLE_HUMITURE_REPORT` (len 4): `0x06, y_l8, y_h8, 0x0A`
+  - `y=report time (500-65535), y=0 disables`
+- `0x07 FREE` (len 2): `0x07, 0x0A` (show initial screen)
+- `0x08 LCD_REG_ADDR` (len 3): `0x08, x, 0x0A`
+- `0x09 LCD_REG_DATA` (len 3): `0x09, x, 0x0A`
+- `0x10 SET_UNCONNECT_BRIGHTNESS` (len 3): `0x10, x, 0x0A`
+- `0x11 SET_UNCONNECT_ORIENTATION` (len 3): `0x11, x, 0x0A` (`x=0-5`)
+- `0x15 SET_BITMAP_WITH_FASTLZ` (len 10): same header as `SET_BITMAP`, compressed payload
+- `0x40 SYSTEM_RESET` (len 2): `0x40, 0x0A`
+
+**Orientation values**
+
+- `PORTRAIT = 0`
+- `REVERSE_PORTRAIT = 1`
+- `LANDSCAPE = 2`
+- `REVERSE_LANDSCAPE = 3`
+- `ROTATE = 5`
+
+**Read commands** (request and response, all end with `0x0A`):
+
+- `0x81 WHO_AM_I` → device info
+- `0x82 READ_ORIENTATION` → `0x82, x, 0x0A`
+- `0x83 READ_BRIGHTNESS` → `0x83, x, 0x0A`
+- `0x90 READ_UNCONNECT_BRIGHTNESS` → `0x90, x, 0x0A`
+- `0x91 READ_UNCONNECT_ORIENTATION` → `0x91, x, 0x0A`
+- `0xC2 READ_SYSTEM_VERSION` → `0xC2, version..., 0x0A`
+- `0xC3 READ_SYSTEM_SERIAL_NUM` → `0xC3, serial..., 0x0A`
+
+**Auto report**
+
+- `0x86 HUMITURE_REPORT` (len 6): `0x86, t_l8, t_h8, h_l8, h_h8, 0x0A`
+  - Temperature/humidity values are `u16`/`i16` and scaled by 100 in the reference UI.
+
+### Reference Implementation (Python)
+
+- `weact_device_setting.py` sends commands to set orientation/brightness and display bitmap data.
+- Uses FastLZ for bitmap updates; chunk size is `width * 4` bytes.
+- Converts RGB to RGB565 little-endian.
+- Uses a background RX thread and reads auto humiture reports when enabled.
+
+## Sources
+
+- [WeActStudio.SystemMonitor README (Support Hardware)](https://raw.githubusercontent.com/WeActStudio/WeActStudio.SystemMonitor/main/README.md) – 3.5-inch specs, USB CDC, sensor.
+- [WeAct Studio System Monitor protocol XLSX v1.1](https://sourceforge.net/projects/weact-studio-system-monitor/files/Doc/WeAct%20Studio%20Display%20Communication%20protocol_v1.1.xlsx/download) – command set, read responses, auto-report.
+- [WeActStudio.SystemMonitor weact_device_setting.py](https://raw.githubusercontent.com/WeActStudio/WeActStudio.SystemMonitor/main/weact_device_setting.py) – detection logic, baud rate, command usage.
+- [WeAct Studio System Monitor SourceForge files](https://sourceforge.net/projects/weact-studio-system-monitor/files/) – hardware tables and docs links.
+- [Bit Trade One WADFS-35 manual](https://bit-trade-one.co.jp/en/wadfs35/manual/) – Windows usage and tool references.
+
+## Open Questions
+
+- [ ] Confirm USB VID/PID and port description strings for the 3.5-inch device on macOS/Linux.
+- [ ] Validate whether the 3.5-inch device requires 1,152,000 baud or supports 115,200.
+- [ ] Verify FastLZ payload format and chunking details for large frames.
+- [ ] Identify any model-specific limitations (brightness range, orientation quirks).
+
+## Related Research
+
+- [[display_fs_v1_research.md]] – 0.96-inch device overview.
diff --git a/AGENTS.md b/AGENTS.md
@@ -1,17 +1,20 @@
-# Project: Display FS V1 (0.96 inch)
+# Project: Display FS V1 (0.96 inch + 3.5 inch)
 
 ## Overview
 
-Standalone CLI application to interact with the Display FS V1 (0.96 inch), detect if it's connected, and display content.
+Standalone CLI application to interact with the Display FS V1 family (0.96 inch + 3.5 inch), detect if it's connected, and display content.
 
 ## Hardware
 
-- **Device:** WeAct Studio Display FS V1 (0.96 inch IPS LCD)
-- **Connection:** USB-C (appears as serial/COM port)
-- **Resolution:** 80x160 pixels (portrait orientation)
-- **Communication:** USB Serial (UART) at 115200 baud
-- **USB Chip:** CH340/CH341 USB-Serial converter
-- **Known VID/PID:** CH340 (1A86:7523), CH341 (1A86:5523)
+- **Device (small):** WeAct Studio Display FS V1 (0.96 inch IPS LCD)
+  - **Resolution:** 80x160 pixels (portrait orientation)
+  - **Communication:** USB CDC/serial (UART), 115200 baud (current CLI)
+  - **USB Chip:** CH340/CH341 USB-Serial converter
+  - **Known VID/PID:** CH340 (1A86:7523), CH341 (1A86:5523)
+- **Device (large):** WeAct Studio Display FS V1 (3.5 inch IPS LCD)
+  - **Resolution:** 320x480 pixels (portrait orientation)
+  - **Communication:** USB2.0 FS (CDC); reference Python app uses 1,152,000 baud
+  - **Sensors:** Humidity + Temperature
 
 ## Project Structure
 

diff --git a/README.md b/README.md
@@ -1,12 +1,12 @@
 # Display FS V1
 
-CLI tool to interact with the WeAct Studio Display FS V1 (0.96 inch IPS LCD).
+CLI tool to interact with the WeAct Studio Display FS V1 family (0.96 inch + 3.5 inch IPS LCDs).
 
 ## Features
 
 - **Standalone executable** - No runtime dependencies, just download and run
 - Auto-detect display via USB (CH340/CH341 USB-Serial)
-- Display text on the 160x80 pixel screen
+- Display text on the 160x80 or 320x480 pixel screen
 - Cross-platform support (Windows, Linux, macOS)
 
 ## Website
@@ -27,14 +27,20 @@ just docs-serve
 
 ## Hardware
 
-| Specification | Value                       |
-|---------------|------------------------------|
-| Device        | WeAct Studio Display FS V1  |
-| Screen Size   | 0.96 inch IPS LCD           |
-| Resolution    | 80x160 pixels (portrait)    |
-| Connection    | USB-C (serial)              |
-| Baud Rate     | 115200                      |
-| USB Chip      | CH340/CH341                 |
+| Specification | 0.96 inch                          | 3.5 inch                          |
+|---------------|------------------------------------|-----------------------------------|
+| Device        | WeAct Studio Display FS V1          | WeAct Studio Display FS V1        |
+| Resolution    | 80x160 pixels (portrait)            | 320x480 pixels (portrait)         |
+| Connection    | USB-C (serial)                      | USB 2.0 FS (CDC)                  |
+| Baud Rate     | 115200                              | 1152000 (reference Python app)    |
+| USB Chip      | CH340/CH341                          | USB CDC                           |
+| Sensors       | None                                | Humidity + Temperature            |
+
+## Model Detection
+
+The CLI auto-detects the display model by VID/PID and USB product strings. If detection is
+ambiguous, pass `--model small` or `--model large` and, if needed, override the baud rate with
+`--baud-rate`.
 
 ## Quick Start
 
@@ -134,6 +140,8 @@ Options:
   -d, --delay <SECONDS>         Delay between pages [default: 2.0]
   -l, --loop                    Loop display continuously
       --detect                  Only check if display is connected
+      --model <MODEL>           Force display model: small or large
+      --baud-rate <BAUD>        Override baud rate (advanced)
   -h, --help                    Print help
 ```
 

diff --git a/site/README.md b/site/README.md
@@ -1,6 +1,6 @@
 # Display FS V1 Site
 
-Static HTML landing page for GitHub Pages.
+Static HTML landing page for GitHub Pages, covering both 0.96" and 3.5" Display FS V1 devices.
 
 ## Local preview