Godot + Arduino series: companion project code

Self-contained project code for the "Godot Isn't Just for Games" series:
Arduino sketches, the Python serial<->UDP bridge, and the Godot 4 projects,
one folder per article.

godot-arduino-1-led-first-light/arduino/bridge/ledtest.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+"""
+ledtest.py  —  isolate the bridge's receive path from Godot.
+
+Sends a single LED command straight to the bridge's command port, exactly like
+Godot does. If the running bridge prints "cmd L1 ... -> serial" (and the LED
+lights), the bridge's receive side is fine and any failure is on Godot's end.
+If the bridge stays silent even for this, the problem is the bridge/binding.
+
+Usage (with bridge.py already running):
+    python ledtest.py L1     # turn LED on
+    python ledtest.py L0     # turn LED off
+"""
+
+import socket
+import sys
+
+msg = (sys.argv[1] if len(sys.argv) > 1 else "L1").encode()
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+sock.sendto(msg, ("127.0.0.1", 4243))
+print(f"sent {msg!r} to 127.0.0.1:4243")