Loudspeaker and microphone for FCDEV3B

[Mychaela Falconia]

Hello FC community,

For those of you who have FCDEV3B boards but lack the loudspeaker and
microphone parts for exercising voice calls, I finally have some parts
which I can officially recommend.

For the loudspeaker, I was originally trying to use tiny speaker parts
that are designed for use in cellphones, and I kept getting very quiet
acoustic output - too quiet for practical use on a lab bench.  Then
someone educated me that those cellphone speakers require special
mechanical/acoustic design, and that for open use on a lab bench I
should use a physically larger speaker instead.  I am now using this
5 cm diameter speaker from SparkFun, and it works great:

https://www.sparkfun.com/products/9151

For the microphone I am using this part from Digi-Key:

https://www.digikey.com/products/en?keywords=CMC-9745-130T

I chose this microphone part also because of its larger size - one can
get really tiny microphone parts, and they don't have the same issue
as speakers, but try soldering wires to one of those tiny cellphone-
sized mic parts.

Both of the above parts (the loudspeaker and the mic) are now
officially recommended for use with our FCDEV3B boards for the purpose
of exercising GSM voice calls and Calypso DSP audio functions such as
ringtone melody generation.

Both parts need to be outfitted with wires and connectors before they
can be connected to an FCDEV3B, and this outfitting requires soldering
and crimping.  You need to take a pair of wires, solder one end to the
speaker or mic, then crimp female terminals (e.g., Molex 70058 series)
onto the other end and insert them into a two-position crimp housing,
producing a connector that will mate with the two-post header on the
FCDEV3B.  Alternatively, you can take pre-crimped "dupont" jumper
wires with female terminations on one end, keep that end intact, then
cut off the other end and solder it to the speaker or mic.

I can supply ready-to-use loudspeaker and mic contraptions for the
cost of labor (the cost of the parts is negligible, the main issue is
the soldering and crimping labor), or you can make them yourself as
described above.

Happy hacking,
Mychaela aka The Mother