I would like to solicit comments regarding a proposed new packet format.
It is actually a one byte extension of RAW format (format 05) called RawWithDelta.
Regarding air pressure reported for the environmental (weather) considerations: in addition to the current value, the change is considered important. It is generally considered that increasing air pressure indicates a change to fair weather and a decrease a change for stormy weather.
Regarding temperature it is desirable to know whether the temperature is greater than previously which may be interpreted that the temperature will continue to rise, at least in the near future.
Similarly with humidity.
I would like to propose 1 additional byte as a set of 3 2-bit fields to indicate recent change of temperature, humidity and air pressure (total 6 bits with 2 for future usage).
00 indicates no change (or small enough to be considered insignificant),
01 indicates a significant reduction in the value,
10 indicates a significant increase and
11 indicates that either the current or previous value was invalid.
- Will previous time period of 1 hour provide a good reference?
2a) Is a value of 1 degree centigrade a good choice for significant change?
2b) Is a value of 5% a good choice for a significant change in humidity?
2c) Is a value of 2hPa a good choice for a significant change in air pressure?
As an example:
If the average air pressure during the previous hour was 1002 and the current value is 1020, the air pressure delta bits would be 10.
A) The android phone app can show a graph of values but only if the tag is continuously available.
B) The iOS version cannot show history because of the apple restriction prohibiting receiving packets when the app in not in foreground. .
C) The RuuviCollector - InfluxDB - Grafana on RaspberyPi is an excellent set of hardware and software which can be used to infer trends but it can only do so when the tag is within range for an extended period.
D) Parsing this new packet is simply parsing the RAW (format 05 ) packet and then parsing the additional byte.
E) I am in the process of finalizing the code additions which require a one line function call in the main program and additions to the packet formatting module.