ATtiny85 Paddle Decoder - Improved INO Files

🎯 Purpose

These improved INO files are specifically designed to work with:

USB Device: Van Ooijen Technische Informatica Free shared USB VID/PID
VID:PID: 16c0:05e4
Type: USB MIDI device
Hardware: ATtiny85 Digispark board

📁 Available Versions

1. paddle_decoder_vusb.ino (RECOMMENDED)

Best for: Most users, first try this one

Features:

Clean, well-structured code
Proper debouncing (5ms)
LED pulse feedback
MIDI notes: 60 (Dit) and 62 (Dah)
Full velocity (127) on note on
Tested timing parameters

When to use: Start with this version. It has the best balance of features and reliability.

2. paddle_decoder_alt.ino

Best for: Alternative implementation if first version has issues

Features:

More modular code structure
Extended debouncing (8ms)
Structured state management
Better code organization
Diagnostic startup sequence

When to use: If paddle_decoder_vusb.ino doesn't work or you need more structured code for modifications.

3. paddle_decoder_diagnostic.ino

Best for: Troubleshooting and debugging

Features:

Extended LED diagnostics
Multiple startup patterns to confirm firmware load
Heartbeat LED (flashes every 10 seconds)
Both Note Off methods (standard and velocity 0)
Press counting
Special "both paddles" indicator

LED Patterns:

5 fast blinks = Firmware loaded OK
1 long blink = USB initialization
3 medium blinks = MIDI ready
Quick flash = Paddle press detected
Continuous on = Both paddles pressed
Brief flash every 10s = Heartbeat (firmware alive)

When to use: When you need to verify that the firmware is loaded and running, or troubleshoot communication issues.

🔧 Key Improvements Over Original

Problem with Original

The original paddle_decoder.ino may have issues with:

MIDI timing
USB enumeration with specific VID/PID
Debounce handling
LED feedback on shared USB pin

What's Fixed

Better Debouncing: Increased from 10ms to configurable values
Improved MIDI Sending: Uses both NoteOff and NoteOn(velocity=0) methods
LED Management: Timed LED pulses instead of direct control
State Tracking: Better state machines for paddle monitoring
USB Stability: More frequent DigiMIDI.update() calls
Diagnostic Support: Multiple versions for troubleshooting

🚀 Installation Instructions

Step 1: Arduino IDE Setup

# Install Arduino IDE if not already installed
# Add Digispark board support:
# File -> Preferences -> Additional Board Manager URLs
# Add: http://digistump.com/package_digistump_index.json

Step 2: Install Board and Library

1. Tools -> Board -> Boards Manager
2. Search for "Digistump AVR Boards"
3. Click Install

4. Sketch -> Include Library -> Manage Libraries  
5. Search for "DigiMIDI"
6. Install DigiMIDI library

Step 3: Select Board

Tools -> Board -> Digispark (Default - 16.5mhz)

Step 4: Choose Your Version

For first attempt: Open paddle_decoder_vusb.ino
If issues persist: Try paddle_decoder_alt.ino
For debugging: Use paddle_decoder_diagnostic.ino

Step 5: Upload

1. Sketch -> Upload
2. Wait for "Plug in device now..."
3. Plug in Digispark USB
4. Wait for upload to complete
5. Digispark will reboot automatically

🔌 Hardware Connections

ATtiny85 Digispark          Paddle
─────────────────          ──────
P2 (Pin 2)       ───────>  LEFT contact (Dit)
P0 (Pin 0)       ───────>  RIGHT contact (Dah)
GND              ───────>  Common Ground
P1 (Pin 1)       ───────>  [Optional LED + resistor to GND]

USB Connection   ───────>  Computer USB port

Pin Details

P2 (Dit): Use internal pullup, LOW when pressed
P0 (Dah): Use internal pullup, LOW when pressed
P1 (LED): Can add external LED for brighter indication
P3/P4: Used by V-USB (don't connect anything)

🧪 Testing Steps

1. Verify Firmware Upload

After uploading, you should see LED blink pattern:

vusb: 5 fast blinks
alt: 5 fast blinks + pause + 3 medium blinks
diagnostic: 5 fast + 1 long + 3 medium blinks

2. Check USB Enumeration

# On Linux:
lsusb | grep "16c0:05e4"

# Should show:
Bus 001 Device XXX: ID 16c0:05e4 Van Ooijen Technische Informatica

# Check MIDI device:
amidi -l

# Should show something like:
Dir Device    Name
IO  hw:X,0,0  Digispark MIDI

3. Test Paddle Input

# Monitor MIDI messages (Linux):
aseqdump -p "Digispark"

# Press LEFT paddle -> Should see: Note On, note 60
# Release LEFT paddle -> Should see: Note Off, note 60
# Press RIGHT paddle -> Should see: Note On, note 62
# Release RIGHT paddle -> Should see: Note Off, note 62

4. Run Your Rust Application

cd /home/developer/rust/paddle_decoder_cross_platform
cargo run --release

🐛 Troubleshooting

Issue: Device not recognized

Symptoms: lsusb doesn't show 16c0:05e4

Solutions:

Try different USB port
Try USB 2.0 port instead of 3.0
Check if udev rules are needed (see below)
Re-upload firmware
Try the diagnostic version to verify firmware is running

Issue: MIDI device not appearing

Symptoms: amidi -l shows no device

Solutions:

Check kernel modules: lsmod | grep snd_seq
Load ALSA sequencer: sudo modprobe snd-seq
Check dmesg for errors: dmesg | tail -20
Verify VID:PID in lsusb

Issue: Paddle presses not detected

Symptoms: LED doesn't flash, no MIDI messages

Solutions:

Check paddle wiring
Test with multimeter (continuity test)
Upload diagnostic version
Verify pullup resistors are working (measure voltage on P0/P2)

Issue: Wrong MIDI notes received

Check: Make sure Rust app is looking for notes 60 and 62, not 1 and 2

Note Mapping:

Original: Note 1 (Dit), Note 2 (Dah)
New versions: Note 60 (Dit), Note 62 (Dah)

Issue: Erratic behavior

Solutions:

Increase debounce time in code
Add 0.1µF capacitor across paddle contacts
Check for electrical noise
Use shielded cable for paddle

📝 udev Rules (Linux)

If you get permission errors, create udev rule:

sudo nano /etc/udev/rules.d/49-digispark.rules

Add:

# Digispark ATtiny85 MIDI
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="05e4", MODE:="0666"
KERNEL=="midi*", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="05e4", MODE:="0666"

Reload rules:

sudo udevadm control --reload-rules
sudo udevadm trigger

🔄 Updating Your Rust Application

The new INO files use Note 60 and Note 62 instead of Note 1 and Note 2.

If your Rust code checks for notes 1 and 2:

Find (in src/main.rs):

if message.message == 1 {  // Dit
    // ...
}
if message.message == 2 {  // Dah
    // ...
}

Replace with:

if message.message == 60 {  // Dit (Middle C)
    // ...
}
if message.message == 62 {  // Dah (D note)
    // ...
}

Alternative: Keep notes 1 and 2

If you want to keep your Rust app unchanged, edit the INO files:

Change:

#define NOTE_DIT  60
#define NOTE_DAH  62

To:

#define NOTE_DIT  1
#define NOTE_DAH  2

📊 MIDI Message Format

All versions send standard MIDI messages:

Note On (paddle pressed):

Status: 0x90 (Note On, Channel 1)
Note: 60 (Dit) or 62 (Dah)
Velocity: 127 (full)

Note Off (paddle released):

Method 1: Status 0x80, Note, Velocity 0
Method 2: Status 0x90, Note, Velocity 0
(diagnostic version sends both for compatibility)

🎯 Which Version Should I Use?

Start here → paddle_decoder_vusb.ino
    ↓
    Works? ✅ → Great! You're done.
    ↓
    No? ❌
    ↓
Try → paddle_decoder_alt.ino  
    ↓
    Works? ✅ → Great! You're done.
    ↓
    No? ❌
    ↓
Try → paddle_decoder_diagnostic.ino
    ↓
    Check LED patterns
    ↓
    LED blinks? ✅ → Firmware uploaded OK
        ↓
        → Check USB enumeration (lsusb)
        → Check MIDI device (amidi -l)
        → Check dmesg for errors
    ↓
    No LED? ❌ → Re-upload firmware
        → Try different USB port
        → Check Digispark board

✅ Success Checklist

Arduino IDE installed with Digispark support
DigiMIDI library installed
Firmware uploaded successfully
LED blinks on startup
Device appears in lsusb as 16c0:05e4
MIDI device appears in amidi -l
LED flashes when paddle pressed
MIDI messages visible in aseqdump
Rust application receives MIDI events

📞 Still Having Issues?

Check LED patterns - Use diagnostic version
Verify USB enumeration - Run lsusb
Check MIDI subsystem - Run amidi -l
Monitor system logs - Run dmesg -w
Test with aseqdump - Verify MIDI messages
Check hardware - Test paddle continuity

📚 Additional Resources

Digispark Wiki: http://digistump.com/wiki/
V-USB Project: https://www.obdev.at/products/vusb/
MIDI Specification: https://www.midi.org/specifications
DigiMIDI Library: https://github.com/digistump/DigisparkArduinoIntegration

🛠️ Development Notes

All three versions:

Use DigiMIDI library for USB MIDI
Support VID:PID 16c0:05e4
Include debouncing
Provide LED feedback
Send standard MIDI Note On/Off messages
Are compatible with the Rust decoder application

Choose the version that works best for your setup!

73! 📻 DD6DS

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ATtiny85 Paddle Decoder - Improved INO Files

🎯 Purpose

📁 Available Versions

1. paddle_decoder_vusb.ino (RECOMMENDED)

2. paddle_decoder_alt.ino

3. paddle_decoder_diagnostic.ino

🔧 Key Improvements Over Original

Problem with Original

What's Fixed

🚀 Installation Instructions

Step 1: Arduino IDE Setup

Step 2: Install Board and Library

Step 3: Select Board

Step 4: Choose Your Version

Step 5: Upload

🔌 Hardware Connections

Pin Details

🧪 Testing Steps

1. Verify Firmware Upload

2. Check USB Enumeration

3. Test Paddle Input

4. Run Your Rust Application

🐛 Troubleshooting

Issue: Device not recognized

Issue: MIDI device not appearing

Issue: Paddle presses not detected

Issue: Wrong MIDI notes received

Issue: Erratic behavior

📝 udev Rules (Linux)

🔄 Updating Your Rust Application

If your Rust code checks for notes 1 and 2:

Alternative: Keep notes 1 and 2

📊 MIDI Message Format

🎯 Which Version Should I Use?

✅ Success Checklist

📞 Still Having Issues?

📚 Additional Resources

🛠️ Development Notes