CSR8635 Breakout v1.0

Bluetooth audio breakout. Was selling on Tindie for $3–5 each; the remainder was moved to Amazon at $6.99. Many were given away until stock was gone.

Note: There are three main variants of these boards with different pin layouts:

1. Commonly listed as BTM-835B - this board has pins on all sides and requires an external antenna. It is generally a board with blue solder mask.
2. Commonly listed as BTM835 - this board generally has it’s chip angled at 45° and has an equal amount of pins on both of the long sides. This one generally has a blue solder mask.
3. Commonly listed as BC8635 - Usually has green solder mask and the two long sides have 14 and 15 pins respectively.

Why did you make it?

I was working on building a Bluetooth audio headset but didn’t realize how small the pins on these modules are. For prototyping my device, I wanted to be able to use this board on a breadboard and have a visual reference to the pinouts.