From 84514c7956c0c52497674400aa551ab5d29be7e6 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Sun, 7 Dec 2025 15:06:45 +0000
Subject: [PATCH] add gpio monitor scipt

detects which gpio inputs are changing
---
 gpio-monitor.py | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 gpio-monitor.py

diff --git a/gpio-monitor.py b/gpio-monitor.py
new file mode 100644
index 0000000..7bd020c
--- /dev/null
+++ b/gpio-monitor.py
@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+"""
+GPIO‑monitor.py
+
+* Sets every usable BCM pin as an input (pull‑down default)
+* Saves the last read state of each pin
+* In an infinite loop it polls the pins (≈10 ms per pass)
+* When one or more pins change it prints:
+      - Which pins changed and old→new values
+      - The full 32‑bit snapshot as a binary string (MSB = highest pin)
+
+Run as root (or a user in the *gpio* group):
+    sudo python3 GPIO‑monitor.py
+Press Ctrl‑C to stop – the script cleans up the GPIO pins.
+"""
+
+import sys
+import time
+import signal
+import RPi.GPIO as GPIO
+
+# ----------------------------------------------------------------------
+# 1️⃣  Pin list – all BCM pins that exist on the 40‑pin header
+# ----------------------------------------------------------------------
+GPIO_PINS = [
+    2, 3, 4, 5, 6, 7, 8, 9,
+    10, 11, 12, 13, 14, 15, 16, 17,
+    18, 19, 20, 21, 22, 23, 24, 25,
+    26, 27
+]
+
+# ----------------------------------------------------------------------
+# 2️⃣  Initialise GPIO
+# ----------------------------------------------------------------------
+GPIO.setmode(GPIO.BCM)
+
+# keep only those pins we can actually configure
+active_pins = []
+failed = []
+
+for pin in GPIO_PINS:
+    try:
+        GPIO.setup(pin, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
+        active_pins.append(pin)
+    except Exception as e:
+        failed.append((pin, str(e)))
+
+if failed:
+    sys.stderr.write("⚠️  Could not initialise the following pins (they will be ignored):\n")
+    for p, msg in failed:
+        sys.stderr.write(f"    Pin {p}: {msg}\n")
+
+# ----------------------------------------------------------------------
+# 3️⃣  Helper to read the current snapshot (dict pin→0/1)
+# ----------------------------------------------------------------------
+def read_all():
+    return {pin: GPIO.input(pin) for pin in active_pins}
+
+# ----------------------------------------------------------------------
+# 4️⃣  Signal handling – graceful exit on Ctrl‑C / SIGTERM
+# ----------------------------------------------------------------------
+keep_running = True
+
+def _handle_exit(signum, frame):
+    global keep_running
+    keep_running = False
+
+signal.signal(signal.SIGINT,  _handle_exit)   # Ctrl‑C
+signal.signal(signal.SIGTERM, _handle_exit)
+
+# ----------------------------------------------------------------------
+# 5️⃣  Main monitoring loop
+# ----------------------------------------------------------------------
+prev_state = read_all()        # initial snapshot
+
+print("🔎 Monitoring {} GPIO pins – press Ctrl‑C to stop".format(len(active_pins)))
+while keep_running:
+    cur_state = read_all()
+
+    # Find pins whose value differed from the previous snapshot
+    changed = [(pin, prev_state[pin], cur_state[pin])
+               for pin in active_pins
+               if prev_state[pin] != cur_state[pin]]
+
+    if changed:
+        # Build a readable change list  e.g. "4:0→1, 17:1→0"
+        changes_txt = ", ".join(f"{pin}:{old}→{new}" for pin, old, new in changed)
+
+        # Build a compact binary view – 32‑bit with pins sorted ascending
+        # (higher pins become more significant bits)
+        bits = "".join(str(cur_state[p]) for p in sorted(active_pins, reverse=True))
+        # Pad to a multiple of 4 for readability
+        pad_len = (4 - len(bits) % 4) % 4
+        bits = "0" * pad_len + bits
+
+        print(f"[{time.strftime('%H:%M:%S')}] Change detected – {changes_txt}")
+        print(f"    Current snapshot: 0b{bits}")
+
+        # Update reference for the next iteration
+        prev_state = cur_state
+
+    # Polling interval – adjust if you need faster/slower response
+    time.sleep(0.01)   # 10 ms
+
+# ----------------------------------------------------------------------
+# 6️⃣  Cleanup
+# ----------------------------------------------------------------------
+GPIO.cleanup()
+print("\n✅ Monitoring stopped – GPIO pins released.")