I have used the imaginatively named Instrument-Tuner with great satisfaction
to tune glockenspiel bars. The software runs under Windows XP or later,
32 or 64 Bit systems, so you need a desktop or laptop to run it on.
(I used a desktop with an external $10 microphone.) According to the
specifications it has "Configurable standard pitch: 380 - 470 Hz."
(Flat enough for the Sonoran?) Download from:
http://www.instrument-tuner.com/index.html 

Jase Haysom.
m.haysom@cartography.id.au.geentroep