135 lines
4.5 KiB
Markdown
135 lines
4.5 KiB
Markdown
# Voron filament dryer
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Arduino Nano firmware for a chamber dryer with four SHT31 humidity/temperature sensors, PID heater control, and PWM fan mixing.
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## Pinout (Arduino Nano)
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All settings below are defined in `include/config.h`.
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| Signal | Nano pin | Notes |
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|--------|----------|-------|
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| I2C SDA | A4 | Shared bus (Wire) |
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| I2C SCL | A5 | Shared bus (Wire) |
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| TCA9548A mux | I2C `0x70` | 8-channel I2C multiplexer |
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| SHT31 sensors | Mux channels 2, 3, 4, 5 | One sensor per channel |
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| SHT31 address | `0x44` | ADDR pin low; use `0x45` if ADDR is high |
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| Fan | D5 | 24 V fan via N-channel MOSFET (hardware PWM) |
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| Heater | A2 | Solid-state relay (burst control) |
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USB serial: **115200 baud**.
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## Dev setup
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### PlatformIO
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This repo uses the PlatformIO CLI (see `.vscode/tasks.json`). If PlatformIO is already installed under `~/.platformio/penv/`, use that directly — you do not need to run the web installer again.
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```bash
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~/.platformio/penv/bin/pio --version
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~/.platformio/penv/bin/pio run # build
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~/.platformio/penv/bin/pio run -t upload # flash
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~/.platformio/penv/bin/pio device monitor # serial monitor
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```
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On Arch Linux / CachyOS, install via the package manager if you prefer:
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```bash
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sudo pacman -S platformio
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```
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If upload cannot find the port, add to `platformio.ini`:
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```ini
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upload_port = /dev/ttyUSB0 ; or /dev/ttyACM0, or a /dev/serial/by-id/... path
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monitor_port = /dev/ttyUSB0
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```
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List available ports:
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```bash
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ls -la /dev/serial/by-id/
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```
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### Serial port permissions (Linux)
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**Recommended — udev rules (one-time, works in Cursor without re-login):**
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```bash
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sudo ./scripts/install-udev-rules.sh
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# unplug and replug the Arduino
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```
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This installs PlatformIO’s `99-platformio-udev.rules` (covers CH340 clone Nanos and other common adapters).
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**Alternative — group membership:**
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```bash
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# Arch / CachyOS
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sudo usermod -aG uucp $USER
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```
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You must **fully log out of the desktop** (not just reboot or open a new terminal) so `id` shows the new group. Cursor’s terminal often keeps the old group list until you restart Cursor after logging out.
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**Immediate workaround** (no sudo, current terminal only):
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```bash
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sg uucp -c "$HOME/.platformio/penv/bin/pio run -t upload"
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```
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Verify access: `test -w /dev/ttyUSB0 && echo ok`
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## First run
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1. Flash firmware and open the serial monitor at 115200 baud.
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2. Confirm `TCA9548A detected` and four valid sensor channels (`ch2`–`ch5`).
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3. Find **stir fan** speed (optional — default is **PWM 178**, ~70%):
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```
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target 0
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fanchars
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```
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Sweeps **30%, 100%, 60%, 80%** fan — heats to max **60°C** corner at **100%** heater. Cools to **40°C** avg between runs. Skips a fan speed if 60°C isn't reached in time. Optional midpoint refine if best isn't at 30% or 100%. Or: `python3 scripts/fan_characterize.py`. When done, `fanchars save` writes the winner to EEPROM (or skip and keep the 178 default).
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4. Tune **heat PI** (stored in EEPROM on autotune complete):
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```
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target 0
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pid default
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autotune 50
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```
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Cutoff follows target (`target + 12°C`, max 95°C) — e.g. ABS at 55°C trips at 67°C corner, nylon at 80°C at 92°C.
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5. Dry at your target — fan runs at stir PWM (default **178**) whenever target > 0, including heat-up. Override with `fan <pwm>`; `fan auto` returns to default. Fan auto-off below 40°C applies only in idle (`target 0`).
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Send `help` over serial for all commands (`target`, `fanchars`, `fan`, `log on/off`, `status`, `pid`, etc.).
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## Raspberry Pi control
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On the Pi, use the curses TUI to set targets and monitor the chamber (SSH with a TTY: `ssh -t`):
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```bash
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python3 scripts/capture_csv.py tui
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```
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Keys: `0` idle · `t` target · `p` material presets · `f`/`F` fan · `l` CSV log · `a` autotune · `:` command · `q` quit
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Headless CSV-only logging (e.g. systemd) is documented in [pi-instructions.md](pi-instructions.md).
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## Filament drying table
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| Filament | Dryer temperature | Drying time (hours) |
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|----------|-------------------|---------------------|
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| PLA | 50–55 °C (122–131 °F) | > 6 |
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| ABS | 60–65 °C (140–149 °F) | > 6 |
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| PETG | 60–65 °C (140–149 °F) | > 6 |
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| Nylon | 70–75 °C (158–167 °F) | > 24 |
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| Desiccants | 60–65 °C (149 °F) | > 12 |
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| PVA | 40–45 °C (104–113 °F) | > 24 |
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| TPU/TPE | 50–55 °C (122–131 °F) | > 8 |
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| ASA | 60–65 °C (140–149 °F) | > 8 |
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| PP | 50–55 °C (122–131 °F) | > 6 |
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| HIPS | 60–65 °C (140–149 °F) | > 8 |
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| PC | 70–75 °C (158–167 °F) | > 12 |
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| PEEK | 120–125 °C (248–257 °F) | > 24 | |