Dear Reader,

Very quick update for something that’s been a lot of work:  you’ll find a new version of the Android App available for download in the Google Play Store.  A new version of the iOS app is awaiting Apple approval (but has been released to the beta group).  The app itself is almost identical, but they are linked to a new version of firmware which you can upload to you Mooshimeter (more on that procedure here).

What’s Changed

1. Logging can now be started and stopped while your smartphone and Mooshimeter are connected
   1. Every sample that is sent over the air while connected is logged to the SD card, so you can look later and see everything you did with the Mooshimeter
   2. If you change the settings of your Mooshimeter while logging, a new title row will appear in the log file
2. The Mooshimeter supports a wider variety of SD cards
   1. The official specs haven’t changed but users were reporting issues with specific models/manufacturers of SD cards.  The new firmware is more permissive and most of those issues are resolved.
3. Battery life while in connection improved

Technical Teaser

To get around the timing issues of talking to an SD card while maintaining a radio connection with a single processor (the CC2540) and no operating system I implemented threads with the standard library setjmp.h routines and some manipulation of the stack pointers.  Since the 8051 has stacks in 3 different memory spaces this was a pain.  I think this technique will be generally useful to others in similar predicaments, I’ll do a technical write-up on it soon.