Update readme with visual curve editor documentation

- Added visual curve editor section
- Updated config documentation for flat curve structure
- Added curve editor troubleshooting
- Added mode API endpoint documentation

usermods/GPU_Fan_Controller/readme.md

@@ -7,9 +7,11 @@ This usermod allows WLED to control PWM PC fans based on GPU temperature data re
 - **Web API Integration**: Receives GPU temperature via HTTP API
 - **Fixed Speed Mode**: Set a constant fan speed (0-100%)
 - **Temperature Curve Mode**: Automatically adjusts fan speed based on temperature
-- **Up to 10 Curve Points**: Define custom temperature-to-speed mappings
+- **Visual Curve Editor**: Interactive web-based graph editor at `/gpu-fan.htm`
+- **Up to 5 Curve Points**: Define custom temperature-to-speed mappings
 - **Safety Fallback**: Automatically runs at 100% if temperature data is lost
 - **WLED UI Integration**: Control and monitor from the WLED web interface
+- **Live Temperature Display**: See current GPU temp and fan speed in real-time
 
 ## Hardware Requirements
 
@@ -35,7 +37,7 @@ This usermod allows WLED to control PWM PC fans based on GPU temperature data re
 
 ### Option 1: Using platformio_override.ini (Recommended)
 
-1. Copy `GPU_Fan_Controller.cpp` to `wled00/usermods/GPU_Fan_Controller/`
+1. Copy the `GPU_Fan_Controller` folder to `wled00/usermods/`
 
 2. Create or edit `platformio_override.ini` in the WLED root directory:
 
@@ -53,6 +55,11 @@ custom_usermods = GPU_Fan_Controller
 pio run -e esp32dev_gpu_fan -t upload
 ```
 
+4. Upload the custom page (optional but recommended):
+```bash
+pio run -e esp32dev_gpu_fan -t uploadfs
+```
+
 ### Option 2: Manual Integration
 
 1. Copy `GPU_Fan_Controller.cpp` to `wled00/usermods/GPU_Fan_Controller/`
@@ -62,6 +69,20 @@ pio run -e esp32dev_gpu_fan -t upload
 -D USERMOD_GPU_FAN_CONTROLLER
 ```
 
+## Visual Curve Editor
+
+Access the visual curve editor at: `http://YOUR_WLED_IP/gpu-fan.htm`
+
+![Curve Editor Screenshot](curve-editor.png)
+
+Features:
+- **Drag points** on the graph to adjust temperature/speed mappings
+- **Live temperature indicator** shows current GPU temp on the graph
+- **Real-time updates** - see fan speed change as you adjust
+- **Table view** for precise value entry
+- **Add/remove points** - use 2-5 curve points
+- **Mode toggle** - switch between Fixed and Curve modes
+
 ## Configuration
 
 ### Via WLED Web Interface
@@ -73,7 +94,9 @@ Navigate to Config → Usermods to configure:
 - **mode**: 0 = Fixed, 1 = Curve
 - **fixed-speed**: Speed percentage when in fixed mode
 - **timeout-ms**: Temperature timeout in milliseconds (default: 10000)
-- **curve**: Array of temperature/speed points
+- **curve-t1 to curve-t5**: Temperature points (°C)
+- **curve-s1 to curve-s5**: Speed points (%)
+- **curve-points**: Number of curve points to use (2-5)
 
 ### Via JSON API
 
@@ -83,13 +106,11 @@ Navigate to Config → Usermods to configure:
     "enabled": true,
     "mode": 1,
     "fixed-speed": 50,
-    "curve-count": 4,
-    "curve": [
-      {"temp": 30, "speed": 30},
-      {"temp": 50, "speed": 50},
-      {"temp": 70, "speed": 75},
-      {"temp": 85, "speed": 100}
-    ]
+    "curve-points": 4,
+    "curve-t1": 30, "curve-s1": 30,
+    "curve-t2": 50, "curve-s2": 50,
+    "curve-t3": 70, "curve-s3": 75,
+    "curve-t4": 85, "curve-s4": 100
   }
 }
 ```
@@ -124,6 +145,21 @@ Content-Type: application/json
 }
 ```
 
+### Set Mode
+
+```http
+POST /json/state
+Content-Type: application/json
+
+{
+  "GPU-Fan": {
+    "mode": 1
+  }
+}
+```
+
+Where mode: 0 = Fixed, 1 = Curve
+
 ### Get Status
 
 ```http
@@ -217,6 +253,11 @@ Speeds between points are linearly interpolated.
 3. Check firewall settings
 4. Test with: `curl -X POST http://ESP32_IP/json/state -H "Content-Type: application/json" -d '{"GPU-Fan":{"temperature":50}}'`
 
+### Curve not saving
+1. Make sure to click "Save" in the curve editor
+2. Check the browser console for errors
+3. Try refreshing the page and re-saving
+
 ### WLED doesn't show the usermod
 1. Ensure the build flag `-D USERMOD_GPU_FAN_CONTROLLER` is set
 2. Rebuild and re-upload the firmware
@@ -229,6 +270,7 @@ Speeds between points are linearly interpolated.
 - **Default GPIO**: 13 (configurable)
 - **Update Interval**: 2 seconds
 - **Safety Timeout**: 10 seconds (runs at 100% if no temperature data)
+- **Max Curve Points**: 5
 
 ## License