diff --git a/bluemaestro/__init__.py b/bluemaestro/__init__.py
index cc3a88e..10c8b41 100755
--- a/bluemaestro/__init__.py
+++ b/bluemaestro/__init__.py
@@ -1,6 +1,7 @@
 #!/usr/bin/python3
 import sqlite3
 # ugh, dataset stumpled over date format
+from itertools import islice
 
 from datetime import datetime
 import logging
@@ -12,12 +13,12 @@ def get_logger():
     return logging.getLogger('bluemaestro')
 
 
-def get_data():
+def get_temperature():
     logger = get_logger()
     merged = {}
-    # TODO could get pretty big ?
 
-    for f in sorted(DIR.glob('*.db')):
+    # TODO how to trigger data download manually?
+    for f in list(sorted(DIR.glob('*.db'))):
         def reg(dt: datetime, value):
             v = merged.get(dt, None)
             if v is None:
@@ -53,15 +54,16 @@ def get_data():
 
     logger.info('total items: %d', len(merged))
     # TODO assert frequency?
-    for k, v in merged.items():
-        # TODO shit. quite a few of them have varying values... how is that freaking possible????
-        # most of them are withing 0.5 degree though... so just ignore?
-        if isinstance(v, set) and len(v) > 1:
-            print(k, v)
+    # for k, v in merged.items():
+    #     # TODO shit. quite a few of them have varying values... how is that freaking possible????
+    #     # most of them are withing 0.5 degree though... so just ignore?
+    #     if isinstance(v, set) and len(v) > 1:
+    #         print(k, v)
+    return merged
 
 def main():
     setup_logzero(get_logger(), level=logging.DEBUG)
-    get_data()
+    get_temperature()
 
 
 if __name__ == '__main__':
diff --git a/bluemaestro/check.py b/bluemaestro/check.py
new file mode 100644
index 0000000..92ca2bb
--- /dev/null
+++ b/bluemaestro/check.py
@@ -0,0 +1,24 @@
+#!/usr/bin/python3
+import logging
+from datetime import timedelta, datetime
+from kython import setup_logzero
+
+from my.bluemaestro import get_temperature, get_logger
+
+def main():
+    setup_logzero(get_logger(), level=logging.DEBUG)
+
+    temps = get_temperature()
+    latest = sorted(temps.items())[:-2]
+
+    prev, _ = latest[-2]
+    last, _ = latest[-1]
+    assert last - prev  < timedelta(minutes=3), f'bad interval! {last - prev}'
+    single = (last - prev).seconds
+
+    NOW = datetime.now()
+    assert NOW - last < timedelta(days=5), f'old backup! {last}'
+
+
+if __name__ == '__main__':
+    main()