diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..baf5917
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "nagios"]
+	path = nagios
+	url = https://git.mount-mockery.de/pylib/nagios.git
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..a7a965e
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,13 @@
+{
+  "autopep8.args": ["--max-line-length=150"],
+  "[python]": {
+    "python.formatting.provider": "none",
+    "editor.defaultFormatter": "ms-python.autopep8",
+    "editor.formatOnSave": true
+  },
+  "editor.fontSize": 14,
+  "emmet.includeLanguages": { "django-html": "html" },
+  "python.testing.pytestArgs": ["-v", "--cov", "--cov-report=xml", "__test__"],
+  "python.testing.unittestEnabled": false,
+  "python.testing.pytestEnabled": true
+}
diff --git a/check_shelly b/check_shelly
new file mode 100755
index 0000000..7459c49
--- /dev/null
+++ b/check_shelly
@@ -0,0 +1,40 @@
+#!/bin/python3
+#
+import argparse
+import json
+import nagios
+import os
+import urllib.request
+
+CHECKS = ['wifi']
+#
+WIFI_QUALITY_ERROR = -30
+WIFI_QUALITY_WARNING = -50
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        prog=os.path.basename(__file__),
+        description='Check shelly for nagios monitorin',
+        # epilog='Text at the bottom of help'
+    )
+    parser.add_argument('-H', '--hostname', required=True)
+    parser.add_argument('-c', '--check', choices=CHECKS, required=True)
+    args = parser.parse_args()
+    #
+    n = nagios.Nagios()
+    status = n.UNKNOWN
+    #
+    with urllib.request.urlopen(f"http://{args.hostname}/status") as response:
+        data = json.load(response)
+    #
+    #
+    if args.check == 'wifi':
+        connected = data['wifi_sta']['connected']
+        quality = data['wifi_sta']['rssi']
+        if not connected or quality > WIFI_QUALITY_ERROR:
+            status = n.ERROR
+        elif quality > WIFI_QUALITY_WARNING:
+            status = n.WARNING
+        else:
+            status = n.OK
+        n.exit(status, f"connected: {connected} - quality: {quality}")
diff --git a/nagios b/nagios
new file mode 160000
index 0000000..3d7f2ec
--- /dev/null
+++ b/nagios
@@ -0,0 +1 @@
+Subproject commit 3d7f2eca05ebe5fdcf17f9e77e47cc62d326874b