power meter added

Author: LC-Linkous

hackrfpy/examples/power_meter.py

@@ -0,0 +1,63 @@
+#! /usr/bin/python3
+##--------------------------------------------------------------------\
+#   hackrfpy  'examples/power_meter.py'
+#   Live signal-strength meter at one frequency, using capture_callback.
+#   Demonstrates the callback API (the binder-style inverted loop) on a real
+#   stream: register a function, get each decoded complex64 block as it
+#   arrives, print a rolling power reading. Read-only / receive-only.
+#
+#   Usage:
+#     uv run python examples/power_meter.py --freq 100e6
+#     uv run python examples/power_meter.py --freq 433.92e6 --rate 2e6
+##--------------------------------------------------------------------\
+import argparse
+import sys
+import numpy as np
+from hackrfpy import HackRF
+
+
+def main():
+    p = argparse.ArgumentParser(description="Live power meter (read-only).")
+    p.add_argument("--freq", default="100e6", help="center frequency Hz")
+    p.add_argument("--rate", default="2e6", help="sample rate sps")
+    p.add_argument("--tools-dir", default=None)
+    args = p.parse_args()
+    freq, rate = float(args.freq), float(args.rate)
+
+    h = HackRF(tools_dir=args.tools_dir)
+    det = h.detect()
+    if not det["ready"]:
+        print(f"no usable HackRF: {det['problem']}", file=sys.stderr)
+        return 1
+
+    print(f"[*] power meter @ {freq/1e6:g} MHz  (Ctrl-C to stop)\n")
+
+    # bar-graph scale in dBFS: roughly noise floor (-90) to full-scale (0)
+    LO, HI, WIDTH = -90.0, 0.0, 40
+
+    def on_block(iq, total):
+        if len(iq) == 0:
+            return
+        # raw dBFS, plus the gain-normalized relative reading (Level 1): the
+        # relative value is comparable across gain settings; pass offset_db
+        # from a calibration run (see examples/calibrate.py) to approximate dBm.
+        db = h.power_dbfs(iq)
+        rel = h.relative_power_db(db, lna=16, vga=20, amp=False)
+        frac = max(0.0, min(1.0, (db - LO) / (HI - LO)))
+        bar = "#" * int(frac * WIDTH)
+        sys.stdout.write(f"\r  {db:7.1f} dBFS  (rel {rel:7.1f} dB)  "
+                         f"|{bar:<{WIDTH}}|")
+        sys.stdout.flush()
+
+    try:
+        # callback fires per block; we never reach a sample cap, so it runs
+        # until Ctrl-C, and the context manager inside reaps the child.
+        h.capture_callback(freq, rate, on_block=on_block)
+    except KeyboardInterrupt:
+        pass
+    print("\n[*] stopped")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())