Add ESP32-C3 SPI slave with ESP-NOW, Raspberry Pi test tools, and updated project structure

- ESP32-C3 SPI slave project with ESP-NOW broadcast functionality
- Raspberry Pi SPI master test tools and CLI for JSON communication
- Merged src/ directory from full branch with lighting controller code
- Updated Pipfile with system install scripts and ESP32 monitoring
- Added comprehensive test suite for SPI communication

test/send_json.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+"""
+CLI to send JSON over SPI to the ESP32-C3 SPI slave.
+
+Examples:
+  ./send_json.py --data '{"d":{"t":"b","br":128},"bar":{"pt":"off"}}'
+  ./send_json.py --file payload.json
+  ./send_json.py --beat --brightness 180 --delay 30 --pattern wave
+"""
+
+import argparse
+import json
+import os
+import sys
+
+# Ensure we can import the local test helper
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+if SCRIPT_DIR not in sys.path:
+    sys.path.insert(0, SCRIPT_DIR)
+
+from spi_master_test import SPIMasterTest  # noqa: E402
+
+
+def build_payload_from_args(args: argparse.Namespace) -> dict:
+    """Build a control payload matching the receiver format from args."""
+    if args.data:
+        try:
+            return json.loads(args.data)
+        except Exception as exc:
+            print(f"Invalid JSON in --data: {exc}")
+            sys.exit(2)
+
+    if args.file:
+        try:
+            with open(args.file, "r", encoding="utf-8") as f:
+                return json.load(f)
+        except Exception as exc:
+            print(f"Failed to read JSON file {args.file}: {exc}")
+            sys.exit(2)
+
+    # Build from individual params (beat or update)
+    msg_type = "b" if args.beat else "u"
+    defaults = {"t": msg_type}
+    if args.brightness is not None:
+        defaults["br"] = int(args.brightness)
+    if args.delay is not None:
+        defaults["dl"] = int(args.delay)
+    if args.n1 is not None:
+        defaults["n1"] = int(args.n1)
+    if args.n2 is not None:
+        defaults["n2"] = int(args.n2)
+    if args.n3 is not None:
+        defaults["n3"] = int(args.n3)
+    if args.step is not None:
+        defaults["s"] = int(args.step)
+
+    bar = {}
+    if args.pattern:
+        bar["pt"] = args.pattern
+    if args.name_value:
+        # Allow sending a specific bar (device) override by name
+        # Usage: --name-value mybar '{"br":200,"pt":"off"}'
+        try:
+            name, value = args.name_value
+            bar = json.loads(value)
+            return {"d": defaults, name: bar}
+        except Exception as exc:
+            print(f"Invalid --name-value: {exc}")
+            sys.exit(2)
+
+    # Default field name could be populated on receiver side via settings.get("name")
+    # We only send defaults and a generic "bar" override here for convenience.
+    return {"d": defaults, "bar": bar}
+
+
+def parse_args() -> argparse.Namespace:
+    p = argparse.ArgumentParser(description="Send JSON over SPI to ESP32-C3")
+    src = p.add_mutually_exclusive_group()
+    src.add_argument("--data", help="Raw JSON string to send")
+    src.add_argument("--file", help="Path to JSON file to send")
+
+    p.add_argument("--beat", action="store_true", help="Send as beat message (t=b)")
+    p.add_argument("--brightness", type=int, help="Brightness (br)")
+    p.add_argument("--delay", type=int, help="Delay (dl)")
+    p.add_argument("--pattern", help="Pattern name (pt)")
+    p.add_argument("--n1", type=int, help="n1 parameter")
+    p.add_argument("--n2", type=int, help="n2 parameter")
+    p.add_argument("--n3", type=int, help="n3 parameter")
+    p.add_argument("--step", type=int, help="step (s)")
+    p.add_argument("--name-value", nargs=2, metavar=("NAME", "JSON"), help="Send override under NAME key with JSON object value")
+
+    # SPI params
+    p.add_argument("--bus", type=int, default=0, help="SPI bus (default 0)")
+    p.add_argument("--device", type=int, default=0, help="SPI device/CE (default 0)")
+    p.add_argument("--speed", type=int, default=1_000_000, help="SPI speed Hz (default 1MHz)")
+    return p.parse_args()
+
+
+def main() -> int:
+    args = parse_args()
+    payload = build_payload_from_args(args)
+
+    spi = SPIMasterTest(bus=args.bus, device=args.device, max_speed_hz=args.speed)
+    try:
+        spi.send_json(payload)
+    finally:
+        spi.cleanup()
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
+
+