Author Topic: Rant: Roving Networks RN-42-SM annoying design tidbit  (Read 1605 times)

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Offline slateraptor

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Rant: Roving Networks RN-42-SM annoying design tidbit
« on: September 24, 2011, 09:24:21 pm »


Sells for $39 USD on DigiKey, which is a sexy price for what you get. I picked one up a few weeks ago knowing that I needed Bluetooth for a prototype that I'm working on. Looks like it'll work nicely since I was shooting for a stacked mezzanine design from the onset.

So why am I so annoyed by this device? Mainly because complacency has made a sucker out of me.

Note the 3 rows for breakout. "Oh, standard 100mil pitch," you might be thinking.

6-pin 100mil pitch header...ok.
Two 12-pin (presumably) 2mm pitch header...w.t.f. mate. ???

I mean really...what genius thought it was a good idea to use two different header pitches on the same small breakout board?!?! And I say presumably because page 8 of the device's datasheet (http://rovingnetworks.com/Docs/Bluetooth-RN-41-SM-DS.pdf) specifies a non-standard 0.080" pitch (yes, to 3 decimal places) as opposed to 2mm ~= 0.079".

In other words, the PCB layout engineer who designed this board ought to be fired with a quickness...after he designs a proper rev2, that is. Just sayin'...  ::)
 

Offline slateraptor

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Re: Rant: Roving Networks RN-42-SM annoying design tidbit
« Reply #1 on: September 25, 2011, 02:59:51 am »
P.S. Spent a few hours on Samtec's website trying pair up low-profile header/socket sets for both 2mm and 100mil. ~$30 USD shipped for 5 modules worth later...these are the part numbers I ordered just in case anyone's interested:

TMS-112-01-T-S - 12-pin 2mm through-hole male header
MMS-112-01-T-SV - 12-pin 2mm through-hole female socket

Nominal 2mm mated clearance = 234mil

TLW-106-05-T-S - 6-pin 100mil through-hole male header
SLW-106-01-T-S - 6-pin 100mil through-hole female socket

Nominal 100mil mated clearance = 240mil

Hopefully tolerances will even out the 6mil nominal difference.  :-\

P.P.S. Really like Samtec's part numbering system...probably because datasheets are top shelf.

P.P.P.S. All this header/socket nonsense serves as strong motivation to design my own breakout board. :-\
« Last Edit: September 25, 2011, 03:02:54 am by slateraptor »
 


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