f1ed809c71
- null-terminated TSV frame: V_bat, IMU (9 fields), RPM, gear - mock RPM ramps 800-8000, gear derived from RPM bands - voltage calibration offset - PROTOCOL.md documents wire format Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
56 lines
1.5 KiB
Markdown
56 lines
1.5 KiB
Markdown
# Arduino
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Sensor interface running on Arduino Nano, communicating with Pi via UART.
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## Sketches
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| Folder | Purpose |
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|--------|---------|
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| `main/` | Primary telemetry sketch |
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## Current Capabilities
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- Battery voltage monitoring (voltage divider on A0)
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- WT61 IMU/gyro via AltSoftSerial (9-axis: accel, gyro, euler angles)
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- Duplex UART to Pi at 115200 baud, 10Hz telemetry output
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- Simple text-based protocol for easy debugging
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## Dependencies
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Install via Arduino Library Manager:
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- **AltSoftSerial** by Paul Stoffregen - for WT61 IMU serial
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## Pin Assignments
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| Pin | Function |
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|-----|----------|
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| A0 | Battery voltage (via divider) |
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| D0 (RX) | Pi UART RX ← Arduino TX |
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| D1 (TX) | Pi UART TX → Arduino RX |
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| D8 | WT61 IMU RX (AltSoftSerial) |
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| D9 | WT61 IMU TX (unused, AltSoftSerial fixed pin) |
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| D13 | Status LED (heartbeat) |
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## Hardware
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- **MCU**: Arduino Nano (ATmega328P)
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- **Pi Connection**: UART at 115200 baud (TX→RX, RX→TX, common GND)
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- **IMU**: WT61 module at 9600 baud, 20Hz output
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- **Voltage sensing**: Resistor divider (100k/47k) scaled for 0-20V input
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## Protocol
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TSV (tab-separated), null-terminated frames at 10Hz. See [PROTOCOL.md](PROTOCOL.md) for full specification.
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## Planned
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- RPM sensing (pulse counting from ignition coil)
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- Gear position indicator
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### Not planned
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- Engine temperature (thermocouple/NTC)
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*Borderline do not want to do, simple but not really useful*
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- Turn signal / high beam status
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*No need to do something the dash already does*
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