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Smallest embedded processor with built-in bluetooth

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trueskew

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May 4, 2013, 10:34:53 AM5/4/13
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I'm hoping to work with an extremely small circuit (half the size of a
dime, and preferably smaller) that needs to talk to a bluetooth host over
SPP. Money isn't an object yet, but it's fair to say that it needs to be
available off the shelf, not a custom chip.

My searches haven't done well, specific size doesn't seem to be part of the
key words. If anyone with experience has suggestions or can point me in
certain directions, I'd appreciate it.

Thanks for reading.
- skew



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Paul Rubin

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May 4, 2013, 1:49:46 PM5/4/13
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"trueskew" <95061@embeddedrelated> writes:
> I'm hoping to work with an extremely small circuit (half the size of a
> dime, and preferably smaller) that needs to talk to a bluetooth host over
> SPP. Money isn't an object yet, but it's fair to say that it needs to be
> available off the shelf, not a custom chip.

There are some TI MSP430's with the BT protocol stack inside. You still
need the RF stuff in a separate package. You might take apart a cheap
BT cellular phone earpiece to see what kind of stuff they use in it. I
doubt that there's more stuff than there really has to be.

I agree it would be neat to have a processor and BT in a single small
module but I've never come across anything like that.

> My searches haven't done well, specific size doesn't seem to be part of the
> key words. If anyone with experience has suggestions or can point me in
> certain directions, I'd appreciate it.

You can usually search on the package type. You can also get bare dice
and use chip-on-board assembly. For small runs I believe that is rather
expensive, but not compared to getting a custom chip made. For big runs
it is quite economical.

mi

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May 4, 2013, 2:39:16 PM5/4/13
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"trueskew" <95061@embeddedrelated> writes:

> I'm hoping to work with an extremely small circuit (half the size of a
> dime, and preferably smaller) that needs to talk to a bluetooth host over
> SPP. Money isn't an object yet, but it's fair to say that it needs to be
> available off the shelf, not a custom chip.


Check TI CC2541 and Nordic Semi nRF51822. nRF is available in 3.5x3.8mm
WLCSP package.

--
Mikko OH2HVJ



Paul Rubin

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May 4, 2013, 3:15:22 PM5/4/13
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mi <mi...@labserve1.i-did-not-set--mail-host-address--so-tickle-me>
writes:
> Check TI CC2541 and Nordic Semi nRF51822. nRF is available in 3.5x3.8mm
> WLCSP package.

Wow, that nRF is really interesting. Any idea what it costs, and
whether it is feasible to deal with WLCSP assembly in prototype
quantities without spending a fortune?

Paul Rubin

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May 4, 2013, 3:27:07 PM5/4/13
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Paul Rubin <no.e...@nospam.invalid> writes:
> Wow, that nRF is really interesting. Any idea what [nRF51822] costs,

Self-followup: it's listed at Mouser starting around $2 in 1k quantity
or $4 in unit quantity. Not bad at all, and there is a $99 development
board. This is quite interesting and it seems to fill a void that's
existed for a while. I'm still wondering about the WLCSP issue, also in
relation to some other devices in that format.

hamilton

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May 4, 2013, 5:36:04 PM5/4/13
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Paul Rubin

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May 4, 2013, 7:24:16 PM5/4/13
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hamilton <hami...@nothere.com> writes:
> http://www.kickstarter.com/projects/1608192864/rfduino-iphone-bluetooth-40-arduino-compatible-boa

That's a really cool-looking board, but as small as it is, I think it's
still too big for some typical wearable applications such as earpieces
and wristwatches. WLCSP seems like the right way to do it.
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