[aprssig] One-wire wx help

[Scott Miller]

> Model is TAI-8570.  On the side is Reader Device ID
> 12D0413400000027 and Writer ID 12EE4134000000D9.  I
> won't be using it for a while so could send it.

That's the one - already got a loaner, thanks.  It's just not quite as easy 
to interface as the other sensors!  Turns out it actually uses a sensor I'm 
already familiar with from paraglider vario projects - the Intersema 
MS5534A.  Nice sensor, but the 1-wire module introduces another protocol 
layer between the host and the 2-wire interface of the sensor.  And once 
you've got the interface working and get the data, there's a fair amount of 
math that needs to be done to apply the factory calibration factors.  Not 
fun in an 8-bit micro with < 8k flash!

I'm sure I'll get it working.  And maybe that'll give me an excuse to work 
again on my paraglider helmet HUD...

Scott
N1VG