checkpoint: working sensor acquisition and axis validation

tools/capture_serial.py

@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+"""Capture Trikke sensor CSV output until interrupted with Ctrl-C."""
+
+import argparse
+import signal
+import sys
+from datetime import datetime
+from pathlib import Path
+
+import serial
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--port", default="/dev/cu.usbmodem1134101")
+    parser.add_argument("--baud", type=int, default=115200)
+    parser.add_argument("--output", type=Path)
+    return parser.parse_args()
+
+
+def main() -> int:
+    args = parse_args()
+    output = args.output or Path("captures") / datetime.now().strftime(
+        "motion_%Y%m%d_%H%M%S.csv"
+    )
+    output.parent.mkdir(parents=True, exist_ok=True)
+
+    stop_requested = False
+
+    def request_stop(_signum: int, _frame: object) -> None:
+        nonlocal stop_requested
+        stop_requested = True
+
+    signal.signal(signal.SIGINT, request_stop)
+    signal.signal(signal.SIGTERM, request_stop)
+
+    sample_count = 0
+    print(f"Recording {args.port} to {output}; press Ctrl-C to stop", flush=True)
+
+    try:
+        with serial.Serial(args.port, args.baud, timeout=0.25) as sensor, output.open(
+            "w", encoding="utf-8", newline=""
+        ) as capture:
+            while not stop_requested:
+                raw_line = sensor.readline()
+                if not raw_line:
+                    continue
+
+                line = raw_line.decode("utf-8", errors="replace").rstrip("\r\n")
+                capture.write(line + "\n")
+
+                if line and line[0].isdigit() and line.count(",") == 13:
+                    sample_count += 1
+                    if sample_count % 500 == 0:
+                        capture.flush()
+                        print(f"  {sample_count} samples captured", flush=True)
+    except serial.SerialException as exc:
+        print(f"Serial error: {exc}", file=sys.stderr)
+        return 1
+
+    print(f"Stopped after {sample_count} samples; saved {output}", flush=True)
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())