LibreTooth: libre hardware bluetooth modules using RN-41 and RN-42
LibreTooth is a side project I developed during my various human-computer interaction device prototyping. In the past, I've been a fan of Sparkfun's Bluetooth Mate Gold, a breakout board for the Roving Networ's RN-41 Class 1 bluetooth module. It's quite superior to other cheaper Bluetooth modules you may find in China through ebay.
Unfortunately, Sparkfun sells it at more than 60$ (which became 70€ on EU sellers) and they also don't release its designs as open hardware. The RN-41 and RN-42 (same as RN-41 but Class 2) can both be bought from Mouser at about 20€ while cheap PCB are available from Dorkbot PDX as usual. So, I decided to design my own Bluetooth Mate inspired hardware: LibreTooth!
LibreTooth is a completely libre hardware project, released under CC-BY-SA 3.0. It has been designed using KiCAD, a Free/Libre/Open-Source Electronic Design Autonomation suite. You find all the schematics and designs for building your Libretooth in the links at the bottom of the page.
Libretooth can both be used with the RN-41 or RN-42. The first one is a Class 1 module which will offer longer distances but higher current consumption while the RN-42 is a Class 2 module offering smaller distances but it is also more energy efficient. The board design is fairly similar to Sparkfun Bluetooth Mate. I just also broke out the reset pin on the bluetooth module to allow programmable reset of bluetooth communication.
Below all the desings:
Bluetooth module on ebay
What is the difference between your product and the product on ebay: Arduino Serial Bluetooth RF Transceiver Module RS232 with backplane?
This is not a product on
This is not a product on sale. It's just a design for a board which I'm using happily. And if you have SMD soldering you can get a PCB made using a service like Dorkbot PDX, get the components needed (mouser.com has them all) and have it for about 30$.
As I had the opportunity of using one of those China modules in one of my projects and I really haven't been satisfied by it, I decided to use something a little bit better.
So, to me this gives you stabler and faster connections. Also note that this modules are certified by many organizations (eg. FCC) so you can design a product around them knowing that your product will also be certified.
Thank you for your quick
Thank you for your quick response, now I get it, by the way, your blog is very helpfull, keep up the good work!
Missing KiCAD sources
Hi Fabio!
Awesome stuff. I think the KiCAD sources link is identical to the Gerbers. Thanks. Oh congrats on the PhD acceptance.
Best regards,
Tom
Missing KiCAD Library
Hi,
Firstly, thank-you for putting the design up. I'm currently staring at two RN-41 modules and was looking around for a footprint for the part (I have already drawn the schematic symbol) and was delighted when I found your page. Many thanks for your efforts.
Alas, Kicad informs me it cannot find this file:
/home/fabio/Documents/Universita/stage_specialistica/kicad/fv_kicad_lib/fv_kicad_lib
I managed to extract the footprint and symbol nonetheless, but it might save confusion later if the files are included.
Regards,
Stuart Longland
Hello Stuart, you can find my
Hello Stuart, you can find my KiCad library here:
http://www.varesano.net/blog/fabio/my-kicad-library
Download it on your system then update the designs to point to the downloaded library.
Hope this helps,
Fabio
Fixed! Thanks for pointing
Fixed! Thanks for pointing that out ;-) Let me know (pictures!) if you build some of these.
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