Yesterday the Rural post delivery person delivered my first parts for this Challenge.
In my concept Forget Me Not : eLDERmon Planning I indicated I wanted to record the Inside and Outside Humidity.
There are other ways to record Humidity but they dont involve using the sponsor's product. ..beside that it would have required a second device just for the Humidity
I'm grateful to EnOcean and element14 for providing two HSM100 Humidity sensors.
They have also gone out of their way to find 315MHz modules, and these came with an STM330C. 
WHY
Many New Zealand homes are not double glazed having been built when a fireplace was standard, along with wooden windows, they didn't really figure in a build.
Many homes have had the wooden window frames replaced with Aluminium (because you don't need to paint them says the salesman), but the single glazing remained.
When fireplaces became a dirty word, drafts seemed to matter so reducing them results in more moisture being trapped, hence condensation on the coldest surface (the window) shows up.
The older radiant heaters with the glowing wire were great for drying the air, but these tend to present other problems and eventually got phased out.
There are energy savings and health benefits to be gained by keeping the house dry.
This website this chart came from is promoting a commercial solution, but does detail some alternative or passive methods.
graph source Humidity and Human Health
Regardless of the causes, houses need to be ventilated by either forced air flow or natural ventilation.
This can make a huge difference, since heating moist air requires a lot more energy.
Solutions
While its understandable to open the windows on a warm day, there may also be benefits to doing this in slightly colder temperatures, since the relative humidity is lower.
The problem is understanding when its suitable and when its not.
If poor old Granny is complaining about being cold, yet the humidity is high, then most of the power bill is used to heat the moisture.
Trying to get her to open the windows on a cold day may not seem sensible, unless you can show the results.
Many folks also open the windows too wide, which then allows the cold air inside, rather than it being warmed behind the glass and then moving into the house.
Hence the figures should show the benefits, or indicate that shutting the window earlier may be advisable.
Passive heating only works if you can get the sun into the house.
Many older houses have large sections which allow more light, but if the sun is blocked by lace or net curtains, then its not going to get inside.
So combining temperature and Humidity with lux level might give the results.
Whatever solution is used, having the figures helps to establish what should work.
Since New Zealand rarely has two days the same, it may take a while to establish the right solution.
Hardware
I have seen the brochure and the picture. I even downloaded the mechanical drawings, but I wasn't ready for the size.
photo source me, myself and I
The business end is on the lower left and the second photo shows it against a Micro USB (yes the same one that fits the Raspberry Pi)
I did have to consult the mechanical drawings to find which way around these should go.
There is no markings, and the STM3xx manuals say consult the HSM100 documents which don't say either (note to Enocean to include in the next version)
So for this who don't read manuals ..here it is mounted, next to my favourite universal sizer ...an AA battery.
photo source me, myself and I
Of course I had left it charging while I went and did other things, so when you press the button it flashes the led but with nothing to receive it ...
So until some more bits turn up.
Mark
PS the rural delivery this morning left a big package ...scope, Programmer and RPi ...its like Xmas.
