hello,

I’m having problems getting the right values for the temperature if it’s subzero degrees (C). I don’t use the python libs provided by you but “borrowed” the conversion code from xbee_sensor.py because I could find any decent documentation on the format of the 1S sample response.

According to your library a temp is negative, if the first 5 bits of the sample are set to 1, then all you need to do is negate the valued calculated before.

However this gives me wrong results, f.e. -122,62 or -126,69. After a bit of examination I think I have found the problem, is it possible that you have to flip the bits if the temp. is below zero? This would give me plausible results.

Example:

Sensor gives me FF AA as result.

Calculation:

is negative? FF AA & F8 00 != 0 : true

extract the integer: (FF AA & 7F0) >> 4 = 7A (= 122d, 1111010b)

if you flip the bits you’ll get 0000101b which would mean 5 degrees below zero, a plausible value for the temp. outside.

So could anybody give me a hint what’s wrong with the temp. calculation?

Greetings

Chris