175 lines
5.5 KiB
Markdown
175 lines
5.5 KiB
Markdown
# 🔥 Laser CANbus Toolhead PCB
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A compact, robust toolhead board for Klipper-based laser engravers and cutters (CoreXY). This board integrates power supply, laser driver logic, CAN-Bus communication, and input shaping (ADXL345) in the smallest possible space.
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## ✨ Features
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### 🧠 Microcontroller
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- **MCU:** STM32F072CBU6 (Cortex-M0, 48MHz, CAN-capable)
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- **Stability:** 12MHz crystal for maximum CAN-Bus stability
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- **Firmware:** Klipper-compatible
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### 🔗 CAN-Bus Communication
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- **Transceiver:** SN65HVD230 with ESD protection
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- **Termination:** Split termination via solder jumper
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- **Slope Control:** Switchable for EMI optimization
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### 📊 Input Shaping
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- **Sensor:** On-board ADXL345 accelerometer (SPI)
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- **Purpose:** Klipper resonance measurement for perfect print quality
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### ⚡ Laser Power Control
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- **Circuit:** 24V / 4A High-Side Switch (AO4407A P-MOSFET)
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- **Soft-Start:** Limits inrush current (Rise-time ~1.2ms)
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- **Safety:** Hardware pull-down prevents unwanted activation
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### 🎛️ Laser Signal Control
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- **PWM:** 5V Level-shifted via 74AHCT1G125 buffer
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- **Quality:** Clean edges, true hardware PWM via STM32 timer
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- **Compatibility:** Common diode lasers
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### 🔌 Power Supply
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- **Input:** 24V with 250mA PTC fuse and SMF24A TVS diode
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- **5V Rail:** MP2459 Buck converter (up to 60V input tolerant)
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- **3.3V Rail:** XC6206 LDO for MCU and peripherals
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### 🚨 Diagnostics & Monitoring
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- **Power LEDs:** 24V In, 24V Sys, 5V, 3.3V
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- **Status LEDs:** Laser Enable, Laser PWM, Heartbeat
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## 📋 Klipper Configuration
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### Basic MCU Setup
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```ini
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[mcu toolhead]
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canbus_uuid: <your-uuid> # Find with "ls /dev/serial/by-id/*" or "~/klippy-env/bin/python ~/klipper/scripts/canbus_query.py can0"
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[temperature_sensor toolhead_mcu]
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sensor_type: temperature_mcu
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sensor_mcu: toolhead
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```
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### Input Shaping (ADXL345)
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```ini
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[adxl345]
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cs_pin: toolhead:PA4
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spi_bus: spi1
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axes_map: x,y,z
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[resonance_tester]
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accel_chip: adxl345
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probe_points:
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150, 150, 20 # Adjust to your bed size
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```
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### Laser Control
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```ini
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# Laser PWM Signal
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[output_pin laser_pwm]
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pin: toolhead:PB14
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pwm: True
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cycle_time: 0.001 # 1kHz PWM frequency
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shutdown_value: 0 # Safety: laser off during emergency
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# Laser Enable (optional)
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[output_pin laser_enable]
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pin: toolhead:PB15
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value: 0
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shutdown_value: 0
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# Heartbeat LED (optional)
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[output_pin heartbeat]
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pin: toolhead:PA9
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pwm: True
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cycle_time: 1.0
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```
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## 🔌 Pinout & Connector Assignment
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### J101 - Power & CAN Input (Micro-Fit 3.0, 2x2)
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| Pin | Signal | Description |
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|-----|---------|-------------|
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| 1 | **+24V** | Main power input (High Current) |
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| 2 | **GND** | Ground |
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| 3 | **CAN_H** | CAN-Bus High Signal |
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| 4 | **CAN_L** | CAN-Bus Low Signal |
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### J102 - Laser Output (Micro-Fit 3.0, 1x3)
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| Pin | Signal | Description |
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|-----|---------|-------------|
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| 1 | **GND** | Laser Ground |
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| 2 | **PWM** | 5V PWM Signal (Level-Shifted) |
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| 3 | **+24V** | Switched Laser Power (Soft-Start) |
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### Debug/Programming Header (Back Side)
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| Pad | Pin | Signal | Function |
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|-----|-----|---------|----------|
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| 1 | - | **5V** | 5V Supply (from Programmer) |
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| 2 | - | **3.3V** | VTref (Reference Voltage) |
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| 3 | PA13 | **SWDIO** | Serial Wire Debug I/O |
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| 4 | PA14 | **SWCLK** | Serial Wire Debug Clock |
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| 5 | - | **NRST** | Reset Signal |
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| 6 | - | **GND** | Ground |
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> **💡 Bootloader Mode:** To force the STM32 into DFU/Bootloader mode (e.g., for initial flash with Katapult), bridge the **BOOT0** pad with **3.3V** during power-on.
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## 🔧 Installation & Setup
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### 1. CAN-Bus Configuration
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- Set CAN-Bus termination according to position in network
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- Baud rate: 1 Mbit/s (Klipper standard)
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### 2. Firmware Flash
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1. Put board into DFU mode (bridge BOOT0)
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2. Compile Klipper for STM32F072 with CAN support
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3. Flash firmware: `make flash FLASH_DEVICE=<dfu-device>`
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### 3. Find UUID
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```bash
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~/klippy-env/bin/python ~/klipper/scripts/canbus_query.py can0
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```
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## ⚠️ Safety Notes
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- **Laser Safety:** Always wear protective eyewear
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- **Power Supply:** Only operate with 24V DC
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- **Initial Setup:** Slowly ramp up laser power
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- **Emergency:** Hardware pull-down ensures safe state
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## 🛠️ BOM (Bill of Materials) - Highlights
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| Component | Value/Type | Function | Package |
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|-----------|------------|----------|---------|
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| **U101** | STM32F072CBU6 | Main Microcontroller | UFQFPN-48 |
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| **U102** | MP2459GJ-Z | Buck Converter 24V→5V | TSOT-23-8 |
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| **U105** | SN65HVD230DR | CAN-Bus Transceiver | SOIC-8 |
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| **U106** | ADXL343/ADXL345 | 3-Axis Accelerometer | LGA-14 |
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| **Q101** | AO4407A | P-MOSFET (Laser Switch) | SOIC-8 |
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| **D101** | SMF24A | TVS Diode (Overvoltage Protection) | DO-214AC |
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| **F101** | 1812L025 | PTC Fuse 250mA | 1812 |
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| **Y101** | 12MHz | Crystal for CAN Stability | HC-49/S |
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## 🛠️ Technical Specifications
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| Parameter | Value | Unit |
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|-----------|-------|------|
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| **Input Voltage** | 24 ± 2 | V |
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| **Laser Current (max)** | 4 | A |
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| **CAN Baud Rate** | 1 | Mbit/s |
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| **PWM Frequency** | 1 | kHz |
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| **Soft-Start Time** | ~1.2 | ms |
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| **Operating Temperature** | -10 to +70 | °C |
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| **Dimensions** | TBD | mm |
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## 📚 Additional Resources
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- [Klipper Documentation](https://www.klipper3d.org/Config_Reference.html)
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- [CAN-Bus Setup Guide](https://www.klipper3d.org/CANBUS.html)
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- [Input Shaping](https://www.klipper3d.org/Resonance_Compensation.html)
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- [Katapult Firmware Flasher](https://github.com/Arksine/katapult)
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---
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*🇩🇪 Deutsche Version: [Readme.de.md](Readme.de.md)* |