Kevin Jones wrote:
> The base module that the spark fun device uses is only $35.00
>
>
http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMtqO%252bWUGLBzeMW4TCGBne5E>
> and much lower in quantity. However, its a 3.3v device and requires
> SMD soldering skills. The extra dollars to spark fun are for a 5v
> interface and having already soldered to a board that is easier for
> hobbiests to work with.
Kevin, I have a feeling that you don't understand what STM4100 is. It is a
module that has all the features of the SparkFun DIP (on-board 5V regulator,
development-friendly connector), and in addition also has circuitry that
allows it to automatically go "bus-off" when a serial or USB cable is
plugged into the same circuit. It has a much smaller vertical profile, and
requires only a 2x6 2mm header on one side (so it does not intrude as much
on the host PCB).
You get all this, for only $4.95 more than you would pay for the bare RN41
($39.95 vs $35), and $20 less than you would pay for the SparkFun module.
> However, looking at the bottom picture of the device, I'm not sure
> its all that much lower in profile. There are jumpers and connector
> on the bottom of the board. The spark fun module is smooth on the
> bottom, no components.
Here's a picture I just took, of two old lab samples (I apologize for the
quality):
http://maksimov.org/piclist/sparkfun_vs_stm4100.jpgNotice that the connector on STM4100 is female, and the holes go _through_
the PCB.
Sparkfun's module was designed to plug into a breadboard, where space is not
an issue. STM4100 was designed to be used in a production device with a very
low vertical clearance:
http://www.scantool.net/elmscan-5-bluetooth.htmlI hope it all makes better sense now.
Vitaliy
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