every minute.
i debug that right now and do a lot of server.log’s to see what’s happening.
@Chrischi, if you post your code, I can take a look and see what might be wrong. The equation itself is only one line so if you are getting “Nan” returned, it must mean that one of your values is corrupt.
filteredTemperature = filteredTemperature - (filteredTemperature-temperature)*0.05;
i thougt that!
the code is the same, only difference the value is delivered by another function.
looking for a way to catch the scenario of corrupt values.
https://xively.com/feeds/353228423
Testing a little setup here. Got my imp running on a lipo battery which is charged by a solar panel. 
I see a little spike in temperature about 2 hours ago but overall it’s looking great!
yes, not sure what is going on there… just had another spike…
I suspect the power source a bit, since it is most likely a bit noise from the converter making the 5V