fix bugs, harden server, strip-based dithering, update docs

Firmware: - fix 90° rotation (was transpose) - fix Adafruit_Thermal constructor (spurious DTR pin arg) - wire up uploadImage; heatInterval now applied - PSRAM-free strip dithering: 2-row buffers (~1KB) replace 153KB PSRAM alloc - consolidate all pins into config.h; BUTTON_PIN → Config::PIN_BUTTON - constrain contrast/brightness/heat in settings save handler - uploadImage size param int → size_t Server: - canonicalize upload_dir at startup (fixes path traversal guard) - path traversal guard in serve_image - replace unwrap in gallery_data with error handling - IMAGE_WIDTH/IMAGE_HEIGHT named constants Gallery: - innerHTML → createElement (XSS-safe) - encodeURIComponent on image URLs - replace("_"," ") → regex /_/g Docs: rewrite README, clarify GUEST_MANUAL placeholders
2026-06-18 11:23:05 +02:00
parent 2f827c168d
commit 4ec723ef40
12 changed files with 263 additions and 219 deletions
--- a/GUEST_MANUAL.md
+++ b/GUEST_MANUAL.md
@@ -6,11 +6,11 @@ Snap a photo, get a receipt, and view the digital archive instantly.

 ### How to use

-1.  **Frame your shot.** (The lens is slightly wide-angle!)
-2.  **Press the Button.**
-3.  **Wait ~5 seconds.**
-    - **Print:** Collect your physical photo.
-    - **Upload:** The photo is magically sent to the gallery.
+1. **Frame your shot.** (Wide-angle lens — back up a little!)
+2. **Press the button.**
+3. **Wait ~5 seconds.**
+   - A thermal print comes out of the printer.
+   - The photo is uploaded to the live gallery.

 ---

@@ -18,11 +18,12 @@ Snap a photo, get a receipt, and view the digital archive instantly.

 Want to save the photo to your phone?

-1.  Connect to the WiFi: **[Your_WiFi_Name]**
-2.  Scan this code or go to:
-    **http://[YOUR_LAPTOP_IP]:3000/gallery**
-3.  Password: **partytime**
+1. Connect to the WiFi: **[FILL IN: venue WiFi name]**
+2. Go to: **http://[FILL IN: server IP]:3000/gallery**
+3. Password: **[FILL IN: gallery password]**

 _(Ask the host if you can't connect!)_

 ---
+
+> **Host checklist before printing this:** fill in the three `[FILL IN]` fields above.
--- a/README.md
+++ b/README.md
@@ -1,82 +1,131 @@
 # Party Cam: Instant Thermal Camera & Digital Gallery

-A DIY point-and-shoot camera that prints dithered lo-fi photos on thermal receipts and instantly uploads high-res copies to a local Rust server.
+A DIY point-and-shoot that prints dithered lo-fi photos on thermal receipt paper and simultaneously uploads captures to a local Rust web server.
+
+---

 ## Hardware BOM

- **ESP32-CAM**
- **Thermal Printer** (TTL Serial, 5V-9V)
- **Batteries** (Recommended: 2x 18650 Li-Ion in series = 7.4V, powering printer directly + buck converter to 5V for ESP32)
- **Button** (Tactile switch)
- **Programmer**: FTDI Adapter or Arduino Uno (for flashing)
+| Part | Notes |
+| :--- | :--- |
+| ESP32-CAM (AI-Thinker) | Camera + WiFi module |
+| Thermal Printer | TTL serial, 5V–9V |
+| 2× 18650 Li-Ion | In series = 7.4V; powers printer directly + 5V buck converter for ESP32 |
+| Tactile button | Shutter trigger |
+| FTDI adapter or Arduino Uno | For flashing only |
+
+---

 ## Wiring

-### 1. Camera & Printer
+| ESP32-CAM Pin | Component | Function |
+| :--- | :--- | :--- |
+| **5V** | PSU 5V | Power in |
+| **GND** | PSU GND | Common ground |
+| **GPIO 12** | Button | Shutter (other leg → GND) |
+| **GPIO 14** (U1T) | Printer RX | Data to printer |
+| **GPIO 15** (U1R) | Printer TX | Data from printer |
+| **GPIO 4** | Flash LED | Optional built-in flash |

-| ESP32-CAM Pin     | Component  | Function                           |
-| :---------------- | :--------- | :--------------------------------- |
-| **5V**            | PSU 5V     | Power In                           |
-| **GND**           | PSU GND    | Common Ground                      |
-| **GPIO 12**       | Button     | Trigger (Connect other leg to GND) |
-| **GPIO 14** (U1T) | Printer RX | Data TO Printer                    |
-| **GPIO 15** (U1R) | Printer TX | Data FROM Printer                  |
-| **GPIO 4**        | Flash LED  | (Optional) Built-in Flash          |
-
-### 2. Flashing (Using Arduino Uno as Bridge)
-
-_See "How to Flash" section below._
+All pin assignments are in `include/config.h`. Change them there if your wiring differs.

 ---

-## Setup Guide
+## Server Setup

-### A. The Server (Rust)
+Run the server on any machine on the same local network as the camera. It receives uploads and hosts the gallery.

-The server receives images and hosts the gallery for guests.
+### Option A: Docker Compose (recommended)

-1.  **Install Rust:** `curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh`
-2.  **Configure:**
-    Create a `.env` file in the `server` folder:
-    ```ini
-    SERVER_HOST=0.0.0.0
-    SERVER_PORT=3000
-    GALLERY_PASSWORD=partytime
-    UPLOAD_DIR=./uploads
-    ```
-3.  **Run:**
-    ```bash
-    cd server
-    cargo run --release
-    ```
-    _Server will listen on port 3000._
+```bash
+cd server
+docker compose up -d
+```

-### B. The Camera (Firmware)
+Images are saved to `server/party_images/` on the host. To change the gallery password, edit `GALLERY_PASSWORD` in `compose.yml`.

-1.  **Open Project:** Open this folder in VS Code with the PlatformIO extension.
-2.  **Flash Mode Wiring (Arduino Uno Method):**
-    - **Arduino RESET** -> **Arduino GND** (Bypasses Arduino chip).
-    - **Arduino Pin 0 (RX)** -> **ESP32 U0R** (Direct passthrough).
-    - **Arduino Pin 1 (TX)** -> **ESP32 U0T** (Direct passthrough).
-    - **ESP32 IO0** -> **ESP32 GND** (Enables Download Mode).
-3.  **Upload:**
-    - Connect via USB.
-    - Click "Upload".
-    - Press the **RST** button on ESP32 when "Connecting..." appears.
-4.  **Run Mode:**
-    - **Disconnect IO0 from GND.**
-    - Press **RST** to boot.
+### Option B: Cargo (dev)
+
+```bash
+cd server
+cargo run --release
+```
+
+Requires a `.env` file in the `server/` directory:
+
+```ini
+SERVER_HOST=0.0.0.0
+SERVER_PORT=3000
+GALLERY_PASSWORD=partytime
+UPLOAD_DIR=./uploads
+```
+
+`GALLERY_PASSWORD` is required — the server panics at startup without it.

 ---

-## Configuration (First Boot)
+## Firmware Setup

-1.  **Power on** the camera.
-2.  Connect your phone to the WiFi network: `PartyCam-Setup`.
-3.  A captive portal should open (or go to `192.168.4.1`).
-4.  **WiFi:** Select the venue's WiFi (or your phone hotspot).
-5.  **Server URL:** Enter your laptop's IP (e.g., `http://192.168.1.15:3000/upload`).
-6.  **Settings:** Adjust Contrast/Heat if the print is too faint or dark.
-7.  **Save & Reboot.**
+### 1. Configure

-The camera is now live!
+Check `platformio.ini` and make sure `board` matches your actual hardware. The default is `4d_systems_esp32s3_gen4_r8n16` — change it to `ai_thinker_esp32-cam` if using a standard ESP32-CAM. Camera pin definitions in `include/config.h` are pre-set for AI-Thinker.
+
+### 2. Flash (Arduino Uno as bridge)
+
+Wire the Uno as a passthrough:
+- Arduino RESET → Arduino GND (bypasses the Uno chip)
+- Arduino Pin 0 (RX) → ESP32 U0R
+- Arduino Pin 1 (TX) → ESP32 U0T
+- **ESP32 IO0 → ESP32 GND** (enables download mode)
+
+Click **Upload** in PlatformIO, then press RST on the ESP32 when "Connecting…" appears.
+
+### 3. Boot
+
+Disconnect IO0 from GND, press RST. The camera boots.
+
+---
+
+## First Boot Configuration
+
+1. Power on. Camera broadcasts WiFi AP: **`PartyCam-Setup`**.
+2. Connect your phone — a captive portal opens automatically (or go to `192.168.4.1`).
+3. Select the venue WiFi and enter the password.
+4. Set the **Upload URL** to `http://<server-machine-ip>:3000/upload`.
+5. Adjust contrast/heat to taste. **Save & Reboot.**
+
+The portal times out after 3 minutes. If it closes before you save, the camera boots in offline mode (printing still works, upload disabled).
+
+---
+
+## Settings Page
+
+After first boot the settings page is always reachable at:
+
+```
+http://partycam.local
+```
+
+(or the camera's IP address on port 80). Use it to adjust contrast, brightness, flip/mirror, heat density, and the upload URL.
+
+---
+
+## Gallery
+
+```
+http://<server-ip>:3000/gallery
+```
+
+Open from any device on the same network. The browser will prompt for the gallery password. New photos appear automatically — the page polls every 5 seconds.
+
+---
+
+## Customisation
+
+| What | Where |
+| :--- | :--- |
+| Pin assignments | `include/config.h` |
+| Printer baud rate | `include/config.h` → `BAUD_RATE` |
+| Default camera settings | `include/settings_service.h` → `AppSettings` struct defaults |
+| Gallery password | `compose.yml` or `.env` |
+| Capture resolution | `src/camera_service.cpp` → `config.frame_size` (update `IMAGE_WIDTH`/`IMAGE_HEIGHT` in `server/src/main.rs` to match) |
--- a/include/config.h
+++ b/include/config.h
@@ -2,16 +2,32 @@
 #include <Arduino.h>

 namespace Config {
-    // Hardware Pins (ESP32-CAM AI-Thinker)
-    constexpr int PIN_CAM_PWDN = 32;
-    constexpr int PIN_CAM_RESET = -1;
-    // ... (Add standard camera pins here to keep main clean) ...
-    
+    // Camera Pins (ESP32-CAM AI-Thinker)
+    constexpr int PIN_CAM_PWDN    = 32;
+    constexpr int PIN_CAM_RESET   = -1;
+    constexpr int PIN_CAM_XCLK   = 0;
+    constexpr int PIN_CAM_SIOD   = 26;
+    constexpr int PIN_CAM_SIOC   = 27;
+    constexpr int PIN_CAM_Y9     = 35;
+    constexpr int PIN_CAM_Y8     = 34;
+    constexpr int PIN_CAM_Y7     = 39;
+    constexpr int PIN_CAM_Y6     = 36;
+    constexpr int PIN_CAM_Y5     = 21;
+    constexpr int PIN_CAM_Y4     = 19;
+    constexpr int PIN_CAM_Y3     = 18;
+    constexpr int PIN_CAM_Y2     = 5;
+    constexpr int PIN_CAM_VSYNC  = 25;
+    constexpr int PIN_CAM_HREF   = 23;
+    constexpr int PIN_CAM_PCLK   = 22;
+
    // Printer Pins
-    constexpr int PIN_PRINTER_RX = 14; 
+    constexpr int PIN_PRINTER_RX = 14;
    constexpr int PIN_PRINTER_TX = 15;
-    
+
+    // Button
+    constexpr int PIN_BUTTON = 12;
+
    // Settings
-    constexpr int PRINTER_WIDTH = 384; 
    constexpr int BAUD_RATE = 9600; // Check your printer specs (some are 19200)
+    constexpr int PRINTER_SERIAL = 1;
 }
--- a/include/image_processor.h
+++ b/include/image_processor.h
@@ -7,5 +7,5 @@ class ImageProcessor
 {
 public:
    static void processAndPrint(const CameraService::Frame &frame, PrinterService &printer, const AppSettings &settings);
-    static void uploadImage(const uint8_t *bitmap, int size, const String &url);
+    static void uploadImage(const uint8_t *bitmap, size_t size, const String &url);
 };
--- a/include/printer_service.h
+++ b/include/printer_service.h
@@ -24,7 +24,7 @@ public:
    void sleep();
    void feed(int lines);

-    void setHeat(uint8_t heatTime);
+    void setHeat(uint8_t heatTime, uint8_t heatInterval);

    void printBitmap(int w, int h, const uint8_t *bitmap);
    void printText(const String &text);
--- a/server/src/gallery.html
+++ b/server/src/gallery.html
@@ -79,19 +79,32 @@
      }

      function addCard(filename) {
-        const div = document.createElement("div");
-        div.className = "card";
-        div.innerHTML = `
-                <a href="/gallery/img/${filename}" target="_blank">
-                    <img src="/gallery/img/${filename}" loading="lazy" alt="Party Photo">
-                </a>
-                <div class="meta">${filename
-                  .replace("capture_", "")
-                  .replace(".png", "")
-                  .replace("_", " ")}</div>
-            `;
-        // Prepend to show new ones at top
-        gallery.prepend(div);
+        const url = `/gallery/img/${encodeURIComponent(filename)}`;
+        const label = filename
+          .replace("capture_", "")
+          .replace(".png", "")
+          .replace(/_/g, " ");
+
+        const a = document.createElement("a");
+        a.href = url;
+        a.target = "_blank";
+
+        const img = document.createElement("img");
+        img.src = url;
+        img.loading = "lazy";
+        img.alt = "Party Photo";
+        a.appendChild(img);
+
+        const meta = document.createElement("div");
+        meta.className = "meta";
+        meta.textContent = label;
+
+        const card = document.createElement("div");
+        card.className = "card";
+        card.appendChild(a);
+        card.appendChild(meta);
+
+        gallery.prepend(card);
      }

      // Initial load and poll every 5 seconds
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -34,6 +34,7 @@ async fn main() -> anyhow::Result<()> {
        PathBuf::from(env::var("UPLOAD_DIR").unwrap_or_else(|_| "./uploads".to_string()));

    tokio::fs::create_dir_all(&upload_dir).await?;
+    let upload_dir = upload_dir.canonicalize()?;
    let state = Arc::new(AppState {
        upload_dir,
        password,
@@ -89,7 +90,13 @@ async fn gallery_view() -> Html<&'static str> {
 }

 async fn gallery_data(State(state): State<Arc<AppState>>) -> impl IntoResponse {
-    let mut entries = tokio::fs::read_dir(&state.upload_dir).await.unwrap();
+    let mut entries = match tokio::fs::read_dir(&state.upload_dir).await {
+        Ok(e) => e,
+        Err(e) => {
+            tracing::error!("Failed to read upload dir: {}", e);
+            return axum::Json(Vec::<String>::new()).into_response();
+        }
+    };
    let mut images = Vec::new();

    while let Ok(Some(entry)) = entries.next_entry().await {
@@ -104,7 +111,7 @@ async fn gallery_data(State(state): State<Arc<AppState>>) -> impl IntoResponse {
    }

    images.sort_by(|a, b| b.cmp(a));
-    axum::Json(images)
+    axum::Json(images).into_response()
 }

 async fn serve_image(
@@ -112,7 +119,13 @@ async fn serve_image(
    Path(filename): Path<String>,
 ) -> impl IntoResponse {
    let path = state.upload_dir.join(&filename);
-    match tokio::fs::read(&path).await {
+    let Ok(canonical) = path.canonicalize() else {
+        return StatusCode::NOT_FOUND.into_response();
+    };
+    if !canonical.starts_with(&state.upload_dir) {
+        return StatusCode::BAD_REQUEST.into_response();
+    }
+    match tokio::fs::read(&canonical).await {
        Ok(bytes) => ([(header::CONTENT_TYPE, "image/png")], bytes).into_response(),
        Err(_) => StatusCode::NOT_FOUND.into_response(),
    }
@@ -150,10 +163,13 @@ async fn basic_auth(
        .into_response()
 }

+// Must match FRAMESIZE_QVGA rotated 90°: camera captures 320×240, firmware rotates to 240×320.
+const IMAGE_WIDTH: u32 = 240;
+const IMAGE_HEIGHT: u32 = 320;
+
 fn convert_and_save(data: &[u8], path: &PathBuf) -> anyhow::Result<()> {
-    // Dimensions from ESP32 code (240x320)
-    let width = 240;
-    let height = 320;
+    let width = IMAGE_WIDTH;
+    let height = IMAGE_HEIGHT;

    let mut img = GrayImage::new(width, height);

--- a/src/camera_service.cpp
+++ b/src/camera_service.cpp
@@ -2,46 +2,28 @@
 #include "camera_service.h"
 #include "config.h"

-#define PWDN_GPIO_NUM 32
-#define RESET_GPIO_NUM -1
-#define XCLK_GPIO_NUM 0
-#define SIOD_GPIO_NUM 26
-#define SIOC_GPIO_NUM 27
-
-#define Y9_GPIO_NUM 35
-#define Y8_GPIO_NUM 34
-#define Y7_GPIO_NUM 39
-#define Y6_GPIO_NUM 36
-#define Y5_GPIO_NUM 21
-#define Y4_GPIO_NUM 19
-#define Y3_GPIO_NUM 18
-#define Y2_GPIO_NUM 5
-#define VSYNC_GPIO_NUM 25
-#define HREF_GPIO_NUM 23
-#define PCLK_GPIO_NUM 22
-
 void CameraService::init()
 {
    camera_config_t config;

    config.ledc_channel = LEDC_CHANNEL_0;
    config.ledc_timer = LEDC_TIMER_0;
-    config.pin_d0 = Y2_GPIO_NUM;
-    config.pin_d1 = Y3_GPIO_NUM;
-    config.pin_d2 = Y4_GPIO_NUM;
-    config.pin_d3 = Y5_GPIO_NUM;
-    config.pin_d4 = Y6_GPIO_NUM;
-    config.pin_d5 = Y7_GPIO_NUM;
-    config.pin_d6 = Y8_GPIO_NUM;
-    config.pin_d7 = Y9_GPIO_NUM;
-    config.pin_xclk = XCLK_GPIO_NUM;
-    config.pin_pclk = PCLK_GPIO_NUM;
-    config.pin_vsync = VSYNC_GPIO_NUM;
-    config.pin_href = HREF_GPIO_NUM;
-    config.pin_sscb_sda = SIOD_GPIO_NUM;
-    config.pin_sscb_scl = SIOC_GPIO_NUM;
-    config.pin_pwdn = PWDN_GPIO_NUM;
-    config.pin_reset = RESET_GPIO_NUM;
+    config.pin_d0 = Config::PIN_CAM_Y2;
+    config.pin_d1 = Config::PIN_CAM_Y3;
+    config.pin_d2 = Config::PIN_CAM_Y4;
+    config.pin_d3 = Config::PIN_CAM_Y5;
+    config.pin_d4 = Config::PIN_CAM_Y6;
+    config.pin_d5 = Config::PIN_CAM_Y7;
+    config.pin_d6 = Config::PIN_CAM_Y8;
+    config.pin_d7 = Config::PIN_CAM_Y9;
+    config.pin_xclk = Config::PIN_CAM_XCLK;
+    config.pin_pclk = Config::PIN_CAM_PCLK;
+    config.pin_vsync = Config::PIN_CAM_VSYNC;
+    config.pin_href = Config::PIN_CAM_HREF;
+    config.pin_sscb_sda = Config::PIN_CAM_SIOD;
+    config.pin_sscb_scl = Config::PIN_CAM_SIOC;
+    config.pin_pwdn = Config::PIN_CAM_PWDN;
+    config.pin_reset = Config::PIN_CAM_RESET;

    config.xclk_freq_hz = 20000000;

--- a/src/image_processor.cpp
+++ b/src/image_processor.cpp
@@ -7,113 +7,86 @@ void ImageProcessor::processAndPrint(const CameraService::Frame &frame, PrinterS
    if (!frame.isValid())
        return;

-    // 1. Setup Dimensions (Rotate 90 degrees)
-    // Camera is 320x240 (Landscape) -> Printer is 384 wide (Portrait)
-    // We will map Camera Height (240) to Printer Width.
-    // Since 240 < 384, the image will be centered or small.
-    // If you want full width, we must scale, but rotation is cheaper.
-    const int width = frame.getHeight(); // 240
-    const int height = frame.getWidth(); // 320
+    // Rotate 90° CW: source is 320×240 (landscape), output is 240×320 (portrait)
+    // dest[row=y, col=x] = src[row = srcHeight-1-x, col = y]
+    const int width = frame.getHeight();   // 240
+    const int height = frame.getWidth();   // 320
+    const int rowBytes = (width + 7) / 8; // 30

-    // 2. Allocate Buffer in PSRAM
-    // We need int16_t to handle the overflow error during calculation
-    size_t bufSize = width * height * sizeof(int16_t);
-    int16_t *pixels = (int16_t *)heap_caps_malloc(bufSize, MALLOC_CAP_SPIRAM);
+    const uint8_t *src = frame.getData();
+    const int srcWidth = frame.getWidth();   // 320
+    const int srcHeight = frame.getHeight(); // 240

-    if (!pixels)
+    // Two row buffers for Floyd-Steinberg: current row + next-row error accumulator.
+    // ~960 bytes total — fits in internal RAM, no PSRAM required.
+    int16_t *cur_row = (int16_t *)malloc(width * sizeof(int16_t));
+    int16_t *next_row = (int16_t *)calloc(width, sizeof(int16_t));
+    size_t bitmapSize = (size_t)rowBytes * height;
+    uint8_t *bitmap = (uint8_t *)calloc(bitmapSize, 1);
+
+    if (!cur_row || !next_row || !bitmap)
    {
-        Serial.println("[ERR] PSRAM Alloc Failed");
+        free(cur_row);
+        free(next_row);
+        free(bitmap);
+        Serial.println("[ERR] Alloc Failed");
        return;
    }

-    // 3. Rotate & Load
-    const uint8_t *src = frame.getData();
-    // Pre-calculate to save cycles in loop
-    const int srcWidth = frame.getWidth();
-
-    for (int y = 0; y < srcWidth; y++)
-    { // 320 (Source Y)
-        for (int x = 0; x < width; x++)
-        { // 240 (Source X)
-            // 90 Deg Rotation Logic
-            // Dest(x, y) = Src(y, srcWidth - x - 1)
-            // We are mapping the camera buffer to our Dithering Buffer
-            uint8_t val = src[x * srcWidth + y];
-            pixels[y * width + x] = static_cast<int16_t>(val);
-        }
-    }
-
-    // 4. Floyd-Steinberg Dithering
    for (int y = 0; y < height; y++)
    {
+        // Load rotated pixels for this row, folding in accumulated error from previous row
        for (int x = 0; x < width; x++)
        {
-            int16_t oldPixel = pixels[y * width + x];
-            int16_t newPixel = (oldPixel > 128) ? 255 : 0;
+            cur_row[x] = (int16_t)src[(srcHeight - 1 - x) * srcWidth + y] + next_row[x];
+            next_row[x] = 0;
+        }

-            pixels[y * width + x] = newPixel;
+        // Floyd-Steinberg dithering
+        for (int x = 0; x < width; x++)
+        {
+            int16_t oldPixel = cur_row[x];
+            int16_t newPixel = (oldPixel > 128) ? 255 : 0;
+            cur_row[x] = newPixel;
            int16_t error = oldPixel - newPixel;

-            // Distribute Error (Bit shifting is faster than division)
-            // Right: 7/16
            if (x + 1 < width)
-                pixels[y * width + (x + 1)] += (error * 7) >> 4;
+                cur_row[x + 1] += (error * 7) >> 4;

-            // Bottom-Left: 3/16
            if (y + 1 < height)
            {
                if (x - 1 >= 0)
-                    pixels[(y + 1) * width + (x - 1)] += (error * 3) >> 4;
-
-                // Bottom: 5/16
-                pixels[(y + 1) * width + x] += (error * 5) >> 4;
-
-                // Bottom-Right: 1/16
+                    next_row[x - 1] += (error * 3) >> 4;
+                next_row[x] += (error * 5) >> 4;
                if (x + 1 < width)
-                    pixels[(y + 1) * width + (x + 1)] += (error * 1) >> 4;
+                    next_row[x + 1] += (error * 1) >> 4;
            }
        }
-    }

-    // 5. Pack & Print
-    // We pack 8 pixels into 1 byte.
-    // The Adafruit library expects a full bitmap array.
-    // Optimization: We reuse the PSRAM allocation or alloc a smaller one.
-
-    // Row stride must be multiple of 8
-    int rowBytes = (width + 7) / 8;
-    size_t bitmapSize = rowBytes * height;
-    uint8_t *bitmap = (uint8_t *)heap_caps_calloc(bitmapSize, 1, MALLOC_CAP_SPIRAM);
-
-    if (!bitmap)
-    {
-        free(pixels);
-        return;
-    }
-
-    for (int y = 0; y < height; y++)
-    {
+        // Pack row into bitmap
        for (int x = 0; x < width; x++)
        {
-            if (pixels[y * width + x] == 0)
-            { // If black
+            if (cur_row[x] == 0)
                bitmap[y * rowBytes + (x / 8)] |= (1 << (7 - (x % 8)));
-            }
        }
    }

-    printer.setHeat(settings.heatTime);
+    free(cur_row);
+    free(next_row);
+
+    printer.setHeat(settings.heatTime, settings.heatInterval);
    printer.wake();
    printer.printBitmap(width, height, bitmap);
    printer.feed(3);
    printer.sleep();

-    // 6. Cleanup (RAII handled elsewhere, but raw pointers need free)
-    free(pixels);
+    if (settings.enableUpload && settings.uploadUrl.length() > 0)
+        uploadImage(bitmap, bitmapSize, settings.uploadUrl);
+
    free(bitmap);
 }

-void ImageProcessor::uploadImage(const uint8_t *bitmap, int size, const String &url)
+void ImageProcessor::uploadImage(const uint8_t *bitmap, size_t size, const String &url)
 {
    if (WiFi.status() != WL_CONNECTED)
        return;
@@ -125,13 +98,9 @@ void ImageProcessor::uploadImage(const uint8_t *bitmap, int size, const String &
    int responseCode = http.POST((uint8_t *)bitmap, size);

    if (responseCode > 0)
-    {
        Serial.printf("[Upload] Success: %d\n", responseCode);
-    }
    else
-    {
        Serial.printf("[Upload] Failed: %s\n", http.errorToString(responseCode).c_str());
-    }

    http.end();
-}
+}
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,10 +1,10 @@
 #include <Arduino.h>
 #include "camera_service.h"
+#include "config.h"
 #include "printer_service.h"
 #include "image_processor.h"
 #include "settings_service.h"

-const int BUTTON_PIN = 12; // Check your wiring
 unsigned long lastDebounceTime = 0;
 const unsigned long debounceDelay = 200;

@@ -28,7 +28,7 @@ void setup()
  Serial.begin(115200);
  Serial.println("Party Cam Starting...");

-  pinMode(BUTTON_PIN, INPUT_PULLUP);
+  pinMode(Config::PIN_BUTTON, INPUT_PULLUP);

  CameraService::init();
  PrinterService::init();
@@ -45,7 +45,7 @@ void loop()

  settingsService.handle();

-  if (digitalRead(BUTTON_PIN) == LOW)
+  if (digitalRead(Config::PIN_BUTTON) == LOW)
  {
    if ((millis() - lastDebounceTime) > debounceDelay)
    {
--- a/src/printer_service.cpp
+++ b/src/printer_service.cpp
@@ -4,8 +4,8 @@ PrinterService *PrinterService::instance = nullptr;

 PrinterService::PrinterService()
 {
-    printerSerial = new HardwareSerial(1); // replace it with not a magic number
-    printer = new Adafruit_Thermal(printerSerial, Config::PIN_PRINTER_RX);
+    printerSerial = new HardwareSerial(Config::PRINTER_SERIAL);
+    printer = new Adafruit_Thermal(printerSerial);
 }

 void PrinterService::init()
@@ -51,10 +51,8 @@ void PrinterService::printText(const String &text)
    printer->println(text);
 }

-void PrinterService::setHeat(uint8_t heatTime)
+void PrinterService::setHeat(uint8_t heatTime, uint8_t heatInterval)
 {
    constexpr int heatDots = 11;
-    constexpr int heatInterval = 50;
-
    printer->setHeatConfig(heatDots, heatTime, heatInterval);
 }
--- a/src/settings_service.cpp
+++ b/src/settings_service.cpp
@@ -123,9 +123,9 @@ void SettingsService::setupRoutes()

    server.on("/save", HTTP_POST, [this]()
              {
-        if (server.hasArg("contrast")) currentSettings.contrast = server.arg("contrast").toInt();
-        if (server.hasArg("brightness")) currentSettings.brightness = server.arg("brightness").toInt();
-        if (server.hasArg("heat")) currentSettings.heatTime = server.arg("heat").toInt();
+        if (server.hasArg("contrast")) currentSettings.contrast = constrain(server.arg("contrast").toInt(), -2, 2);
+        if (server.hasArg("brightness")) currentSettings.brightness = constrain(server.arg("brightness").toInt(), -2, 2);
+        if (server.hasArg("heat")) currentSettings.heatTime = constrain(server.arg("heat").toInt(), 0, 255);
        currentSettings.uploadUrl = server.arg("url");
        
        currentSettings.vFlip = server.hasArg("vflip");