bugfix

app/helpers/InSyncState.rb

@@ -40,6 +40,7 @@ class InSyncState < StatePattern::State
        next_is_gas = false
        
        # prepare DB record
+       last_reading = Reading.last
        reading = Reading.new
        
        frame_lines.each {| line|
@@ -78,8 +79,7 @@ class InSyncState < StatePattern::State
            end                
          }
         
-        last_reading = Reading.last
-        if last_reading.eql_reading?(reading)
+        if last_reading && last_reading.eql_reading?(reading)
           p "Nothing changed. Do not add to the database"
         else                        
           reading.save