Tiny bluetooth teardown


The folks at SparkFun were startled by how small USB bluetooth adapters had become so they split one open. They noted a few interesting design features. It has a small folded trace antenna on the board edge. The metal USB housing acts as the RF shield. The bluetooth IC is an AS3620QA. Now we wonder what those tiny Buffalo drives look like inside.

Related: Eye-Fi teardown, storage/WiFi in an SD card


  1. Mic says:

    “Now we wonder what those tiny Buffalo drives look like inside.”

    -Please wonder no more! Crack one open, for education sakes of course.

  2. cde says:

    The only bad part about these bluetooth devices is that the led tends to be green instead of blue, and is placed on the underside of the board, so if you are using it on a laptop, it makes it impossible to see the light.

    Also, white versions cost like 20 times more. The regular black version can be had for like 2.30 ~ 3.00 with free ship on DX or ebay.

  3. cde says:

    Also, the version I have has a big through-hole crystal, unlike the version they have.

  4. 56killer says:

    I have one of those. Bought it for like 3 bucks with free shipping and works on my Desktop as well as my iBook.

  5. Alan says:

    Wait don’t they know that kinks in an antenna aren’t good? At least that’s what my engineering class said. Curves are much better because they don’t restrict electron flow.

  6. JoeBlo says:

    They got the part number wrong. If you zoom in on the picture that is on the sparkfun website, it says a53620qa not as3620qa. I still couldn’t find a datasheet though.

  7. kyndal says:

    this article is missing an arduino?

  8. terreurbv says:

    I got the same bleutooth stick only problem is it won’t work in Vista 64bit, can’t installe any drivers.

    And i’ve try’d a lot the damn thing is in the bin now.

  9. luke says:

    these look the same as the ones on DX at about $2.50


    but they work with 64bit
    i used one in my EEE mod about 6 months back


  10. Arduinofeak says:

    Is that chip arduino compatible?

  11. nico says:

    funny how they made the case bigger than actually necessary.

  12. tjhooker says:

    @kyndal: please god no I’m tired of seeing adruino stuff flood these sites. Nobody is making or reversing anything they’re just interfacing and coding.

    That one guy is right about the square antenna, but it’s not going to matter with this application much. The also use too many passive components

  13. MrX says:

    @kyndal shut the fuck up.

    @tjhooker he is trolling.

    This is impressive. Next step, bluetooth on a Mini-B connector for plugging in OTG devices.

  14. Yrb says:

    @terreurbv, you should have removed Windows and kept the Bluetooth.

    The device works well on 64-bit versions of BSD and Linux.


  15. cantido says:

    “Now we wonder what those tiny Buffalo drives look like inside.”

    BGA or epoxy’ed flash on one side, BGA or epoxy’ed “usb mass storage controller” on the other. Exicting stuff!

  16. terreurbv says:

    @Yrb No worry Got a new one (destroy the old one out of frustration) and i’m using Linux.
    Only have Windows for PS and AI… :/

  17. incognito53 says:

    @alan- fwiw, i believe they did that as a type of coil similar to what they use in walkie talkies.. 2.4gig antennas dont exactly need to resonate long distances with bluetooth so its now a major concern as small as it is

  18. incognito53 says:

    now=not… at least in the above instance

  19. vostein says:

    The exposed usb plug in the pic reminds me of the iron man mask…

  20. Laurencium says:

    Arduino is the cancer killing hackaday

  21. Hitek146 says:

    I bought 5 of these for about $2.50 each delivered on ebay a while back, and they work quite well. The only thing I didn’t like is the fact that the placement of the regulator prevents the plug from fully seating in many usb sockets, so there is a bit of exposed metal connector, and the plastic housing does not become flush with the casing of the host device, which partially defeats the purpose of making the plastic casing round instead of square(so that it does not snag and break when hit from the side)…

  22. ajd4096 says:

    I’ve accidently put one of these through the wash a few times.

    After letting it dry thoroughly it still works ok.

  23. Hellmark says:

    I got one of those for $1.72 off ebay last week, and promptly tore it apart. Really amazing how tightly packed everything is. Reassembled, and works great. Insane how things can shrink down.

  24. whatever says:

    _you_ are the cancer killing /hackaday/

    … and arduinos are also cancer …

  25. agent420 says:

    @ allan – “Wait don’t they know that kinks in an antenna aren’t good? At least that’s what my engineering class said. Curves are much better because they don’t restrict electron flow.”

    Actually, the reason kinks are often avoided is because they tend to generate rf as a result. in a conventioanl pcb design you’d want to avoid this, but for an antenna it’s exactly what you want.

  26. Roman D says:

    @allan to expand a little more on what agant420 said the kinks in this particular application are intentional and act as a resonator. That’s a tiny tiny one though, looks smaller then 1/4wave so i’m not sure what it’s tuned too.

  27. Jac says:

    Looks like this one needs some help from a dremel to cut the USB plug a little shorter and to cut the sides off that huge handle…

    My bluetooth adapters are smaller than this one.

  28. cubexombi says:

    I have the 2.50$ one from DX as luke had pointed out, (http://www.dealextreme.com/details.dx/sku.11866) For the price / Size.. you can’t get much better.

    Hell Even while still in the case it’s small enough.

  29. Nate says:

    My lab bought a few of these. Keep in mind that they often all have the same bluetooth id.

  30. Latente says:

    added to “things that lookalike ironman mask”

  31. Wwhat says:

    If you cut the corners off you run the risk of it getting hooked on something, the roundness isn’t a bad idea probably, you don’t want dongles on notebooks to get hooked in the bag as you take them out.
    btw, I noticed the contacts are all the same length, weren’t the power ones originally suppose to be longer according to USB specs so the power is established before the data lines connect?

  32. walt says:

    I cracked one of these open about a month ago. didn’t know that was a feat worthy of being on the interwebs.

  33. id-3678 says:

    walt:didn’t know that was a feat worthy of being on the interwebs.

    I like to see more cracked devices than arduinos. maybe 1 day we wil find an arduino in a kids toy. 8(

  34. lolberto says:

    It isnt really dificult to open them, just some pressure and crack! open!, if you can trace an internal usb port in your mb this lil thingos make for an excellent internal bt module.

    “I like to see more cracked devices than arduinos. maybe 1 day we wil find an arduino in a kids toy. 8(”

    lol that would be amazing. >:)

  35. alex b says:

    The logo on the chip is for “Accel Semi”, which has a page describing a few of their bluetooth chips: http://www.accelsemi.com/en/product/index.htm

    It doesn’t seem to list the AS3620 though. I have a few dongles based on AS3601QC, and I’d love to see a datasheet for that, too :)

  36. dkostas says:

    datasheet for AS3600 is available here:


    I believe that all chips from Accel have similar functionality and pin layout.

    This chip could be Arduino (or any other uc) ready if someone could figure out if the UART, SPI, or I2C pins are accessible on the bluetooth adapter.

  37. insanity says:

    I have just released a new Bluetooth Auditing Application.
    You can find it here: http://h4x.co.cc/bluetoothhacks.html

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