diff --git a/adsb_alerter.py b/adsb_alerter.py
new file mode 100755
index 0000000..0383491
--- /dev/null
+++ b/adsb_alerter.py
@@ -0,0 +1,76 @@
+#!/usr/bin/python3
+"""
+Accept traffic over a port from readsb and send slack messages when 
+aircraft matching argument KML are seen.
+
+TODO:
+- maybe also log to appsheet?  
+"""
+
+from collections import defaultdict
+import datetime
+import requests
+import time
+import threading
+import pytz
+
+import adsb_receiver
+from dbg import dbg, set_dbg_level, log
+from bboxes import Bboxes
+from config import Config
+
+import appsheet_api
+
+SEND_SLACK = True
+TZ_CONVERT = 0 # -7  # UTC conversion
+CONFIG = Config()
+
+def send_slack(text):
+    print(f"Slack msg: {text}")
+    if SEND_SLACK:
+        webhook = CONFIG.private_vars['slack_nearby_webhook']
+        payload = {"text": text}
+        response = requests.post(webhook, json.dumps(payload))
+        print(response)
+    else:
+        print("Skipping slack send")
+
+def bbox_start_change_cb(flight, flight_str):
+    dbg("*** bbox_start_change_cb "+flight_str)
+    t = threading.Thread(target=bbox_change_cb, args=[flight, flight_str])
+    t.start()
+
+def bbox_change_cb(flight, flight_str):
+    local_time = datetime.datetime.fromtimestamp(flight.lastloc.now)
+    log(f"*** bbox_change_cb at {local_time}: {flight_str}")
+
+    flight_id = flight.tail
+    flight_name = flight.flight_id.strip()
+    if not flight_id:
+        flight_id = flight_name
+
+    if "Nearby" in flight_str:
+        send_slack(flight_str)
+
+
+if __name__ == "__main__":
+    # No-GUI mode, see controller.py for GUI
+    import argparse
+
+    parser = argparse.ArgumentParser(description="match flights against kml bounding boxes")
+    parser.add_argument("-d", "--debug", action="store_true")
+    parser.add_argument('file', nargs='+', help="kml files to use")
+    parser.add_argument('--ipaddr', help="IP address to connect to", required=True)
+    parser.add_argument('--port', help="port to connect to", required=True)
+    args = parser.parse_args()
+
+    if args.debug: set_dbg_level(2)
+    else: set_dbg_level(1)
+    bboxes_list = []
+    for f in args.file:
+        bboxes_list.append(Bboxes(f))
+
+    listen = adsb_receiver.setup(args.ipaddr, args.port)
+
+    adsb_receiver.flight_read_loop(listen, bboxes_list, None, None,
+        None, bbox_start_change_cb)