rebuild

WIRING.md

@@ -0,0 +1,198 @@
+# Thermal Printer Wiring Guide for Raspberry Pi 4
+
+## Connection Diagram
+
+```
+Thermal Printer (58mm)                    Raspberry Pi 4
+┌──────────────────┐                      ┌─────────────────────┐
+│                  │                      │                     │
+│  Red (VCC/5V)    ├─────────────────────►│ Pin 4 (5V)          │ ⚠️ May need external PSU
+│                  │                      │                     │
+│  Black (GND)     ├─────────────────────►│ Pin 6 (GND)         │
+│                  │                      │                     │
+│  Green (RX)      ├─────────────────────►│ Pin 8 (GPIO14/TXD)  │ Pi sends data
+│                  │                      │                     │
+│  Yellow (TX)     ├─────────────────────►│ Pin 10 (GPIO15/RXD) │ Pi receives (optional)
+│                  │                      │                     │
+│  Yellow/Green    ├─────────────────────►│ Pin 6 (GND)         │ Shield/extra ground
+│                  │                      │                     │
+└──────────────────┘                      └─────────────────────┘
+```
+
+## Pin Layout (GPIO Header View)
+
+```
+Raspberry Pi 4 GPIO Header (looking down at the board)
+┌─────────────────────────────────────────┐
+│  3V3  [ 1] [ 2]  5V   ← Connect Red here (or use external PSU)
+│ GPIO2 [ 3] [ 4]  5V
+│ GPIO3 [ 5] [ 6]  GND  ← Connect Black + Yellow/Green here
+│ GPIO4 [ 7] [ 8]  GPIO14 (TXD) ← Connect Green here
+│   GND [ 9] [10]  GPIO15 (RXD) ← Connect Yellow here
+│GPIO17 [11] [12]  GPIO18
+│GPIO27 [13] [14]  GND
+│GPIO22 [15] [16]  GPIO23
+│  3V3  [17] [18]  GPIO24
+│GPIO10 [19] [20]  GND
+│ GPIO9 [21] [22]  GPIO25
+│GPIO11 [23] [24]  GPIO8
+│   GND [25] [26]  GPIO7
+│   ... (pins 27-40 not shown)
+└─────────────────────────────────────────┘
+```
+
+## Quick Connection Summary
+
+| Printer Wire | Pi Pin Number | Pi Pin Name | Function |
+|-------------|---------------|-------------|----------|
+| **Red** | **4** | 5V Power | Power supply (⚠️ high current) |
+| **Black** | **6** | Ground | Common ground |
+| **Green** | **8** | GPIO 14 (TXD) | Serial transmit (Pi → Printer) |
+| **Yellow** | **10** | GPIO 15 (RXD) | Serial receive (Printer → Pi, optional) |
+| **Yellow/Green** | **6** | Ground | Shield/secondary ground |
+
+## Testing Steps
+
+### 1. Enable Serial Port on Raspberry Pi
+
+```bash
+# Open configuration
+sudo raspi-config
+
+# Navigate to:
+# 3 Interface Options → I6 Serial Port
+# "Login shell over serial?" → No
+# "Serial port hardware enabled?" → Yes
+# Finish and reboot
+
+sudo reboot
+```
+
+### 2. Verify Serial Device
+
+```bash
+# Check serial device
+ls -l /dev/serial0
+ls -l /dev/ttyAMA0
+
+# Both should exist and point to UART
+```
+
+### 3. Install Test Tools
+
+```bash
+sudo apt update
+sudo apt install python3 python3-pip python3-venv
+
+# Create test environment
+python3 -m venv test_env
+source test_env/bin/activate
+pip install python-escpos pyserial
+```
+
+### 4. Test Print Script
+
+Create `test_printer.py`:
+
+```python
+#!/usr/bin/env python3
+from escpos.printer import Serial
+
+# Try different device paths if needed
+# Common: /dev/serial0, /dev/ttyAMA0, /dev/ttyS0
+try:
+    printer = Serial(
+        devfile='/dev/serial0',  # or /dev/ttyAMA0
+        baudrate=19200,
+        timeout=1
+    )
+    
+    print("Printer initialized successfully!")
+    printer.text("Hello from Raspberry Pi!\n")
+    printer.text("AutoKanban Test Print\n")
+    printer.text("=" * 32 + "\n")
+    printer.cut()
+    print("Print sent successfully!")
+    
+except Exception as e:
+    print(f"Error: {e}")
+    print("\nTroubleshooting:")
+    print("1. Check wiring connections")
+    print("2. Verify serial port is enabled: sudo raspi-config")
+    print("3. Check user is in dialout group: groups")
+    print("4. Try different baudrates: 9600, 19200, 115200")
+    print("5. List available devices: ls -l /dev/tty*")
+```
+
+### 5. Run Test
+
+```bash
+# Make sure user is in dialout group
+sudo usermod -a -G dialout $USER
+# Log out and back in, or:
+newgrp dialout
+
+# Run test
+python3 test_printer.py
+```
+
+## ⚠️ Power Considerations
+
+**Important**: Thermal printers can draw 1-2A during printing. The Pi's 5V pins can provide limited current.
+
+**If the printer doesn't work or the Pi reboots during printing:**
+
+1. Use an external 5V power supply (2A or higher):
+
+   ```
+   External 5V PSU
+   ┌────────────┐
+   │  5V   GND  │
+   │  │     │   │
+   └──┼─────┼───┘
+      │     │
+      │     └──────────┬─► Pi Pin 6 (GND)
+      │                └─► Printer Black wire
+      │
+      └────────────────────► Printer Red wire
+   ```
+
+2. Common ground is critical - connect:
+   - External PSU GND → Printer Black
+   - External PSU GND → Pi GND (Pin 6)
+   - This ensures both devices share the same ground reference
+
+## Troubleshooting
+
+### No output from printer
+
+- Check all connections are secure
+- Verify serial port is enabled: `sudo raspi-config`
+- Check device path: `ls -l /dev/serial*`
+- Try different baudrates: 9600, 19200, 115200
+- Check user permissions: `groups` (should include `dialout`)
+
+### Printer prints garbage
+
+- Wrong baudrate - try 9600 or 19200
+- Wrong wiring - swap TX/RX if needed
+
+### Pi reboots when printing
+
+- Power supply insufficient - use external 5V PSU for printer
+
+### Permission denied
+
+```bash
+sudo usermod -a -G dialout $USER
+# Log out and back in
+```
+
+## Next Steps
+
+Once the test print works:
+
+1. Note the working device path (`/dev/serial0` or `/dev/ttyAMA0`)
+2. Note the working baudrate (likely 19200)
+3. Update these in your AutoKanban `app/main.py`
+4. Set `DEBUG_PRINT_TO_IMAGE = False` for real printing