Initial commit

src/plot.py

@@ -0,0 +1,97 @@
+import pandas as pd
+import matplotlib.pyplot as plt
+from pathlib import Path
+import argparse
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("directory", type=Path, help="Source data directory")
+
+args = parser.parse_args()
+
+INPUT_CSV: Path = args.directory
+
+
+# Width of the artificial pulse, in microseconds.
+# Increase this if the pulses are still hard to see.
+PULSE_WIDTH_US = 500  # 5 ms
+
+# Optional: plot only a smaller time window.
+# Use None to plot the whole recording.
+START_US = None
+END_US = None
+
+
+def build_pulse_trace(edge_times_us, pulse_width_us):
+    """
+    Convert falling-edge timestamps into a drawable square pulse trace.
+
+    Each edge becomes:
+        low before edge
+        high from edge to edge + pulse_width_us
+        low after that
+    """
+    x = []
+    y = []
+
+    for t in edge_times_us:
+        x.extend([t, t, t + pulse_width_us, t + pulse_width_us])
+        y.extend([0, 1, 1, 0])
+
+    return x, y
+
+
+def main():
+    df = pd.read_csv(INPUT_CSV)
+
+    # If the CSV has an index/time column from df_final.to_csv(),
+    # use the first column as time in microseconds.
+    time_col = df.columns[0]
+
+    # If your CSV columns are: index, crank, cam
+    time_us = df[time_col]
+
+    crank_edges = time_us[df["crank"] == 1].to_numpy()
+    cam_edges = time_us[df["cam"] == 1].to_numpy()
+
+    if START_US is not None:
+        crank_edges = crank_edges[crank_edges >= START_US]
+        cam_edges = cam_edges[cam_edges >= START_US]
+
+    if END_US is not None:
+        crank_edges = crank_edges[crank_edges <= END_US]
+        cam_edges = cam_edges[cam_edges <= END_US]
+
+    crank_x, crank_y = build_pulse_trace(crank_edges, PULSE_WIDTH_US)
+    cam_x, cam_y = build_pulse_trace(cam_edges, PULSE_WIDTH_US)
+
+    # Convert microseconds to seconds for a more readable x-axis
+    crank_x = [x / 1_000_000 for x in crank_x]
+    cam_x = [x / 1_000_000 for x in cam_x]
+
+    # Offset cam vertically so both traces are readable
+    crank_y = [y * 0.8 + 0 for y in crank_y]
+    cam_y = [y * 0.8 + 1.2 for y in cam_y]
+
+    plt.figure(figsize=(14, 5))
+
+    plt.plot(crank_x, crank_y, label="Crank")
+    plt.plot(cam_x, cam_y, label="Cam")
+
+    plt.yticks([0.4, 1.6], ["Crank", "Cam"])
+    plt.xlabel("Time [s]")
+    plt.title(f"Crank and Cam Falling Edges, pulse width = {PULSE_WIDTH_US} µs")
+    plt.grid(True)
+    plt.legend()
+
+    if START_US is not None or END_US is not None:
+        start_s = START_US / 1_000_000 if START_US is not None else None
+        end_s = END_US / 1_000_000 if END_US is not None else None
+        plt.xlim(start_s, end_s)
+
+    plt.tight_layout()
+    plt.show()
+
+
+if __name__ == "__main__":
+    main()