I am finally getting around to posting some documentation on bluetooth audio adapter that I intend to make my pcb final.
After a really long wait, I got the parts from spark fun and connected them to a breadboard. First the RN52 breakout board. Since I just want the audio, and no other functionality, I just have to provide power. However, in case in the future I would like to prototype a board with all of the functionality that the chip has to offer I have connected an FTDI breakout to explore the chips programming functions.
On the first try, the board would only remain connected for limited amounts of time to a bluetooth device such as a phone or a laptop. That turned out to be a power issue. The FTDI was backfeeding enough power to power the board, but it was not enough for the broadcast to be stable.
Turns out I was not sending the recommended 6-12 volts to the 3v power breakout board.
Moving on, I experimented with the board to make sure it remained stable once I added the correct voltage, and everything worked great. I was able to listen to music for 4 hours with no interruptions. It is not line level signal, so it may be in the future I will add a amplifier to the output of the RN52.
On to the schematic,
I am going to acid etch since my traces are very small and the printer resolution is better than the other mill.
here are the results of my trying to toner transfer onto the copper.
needless to say that was not as easy as I had thought it would be. It turns out I was not heating it up hot enough to get a clean transfer.
I have since continuity tested all of the connections on the board, and out of the two boards there was only one problem but it could have been catastrophic. The VCC was connected to the ground plane due to the two traces being to close and the acid failing to etch the copper away. I used a xacto knife to cut away the copper and tested again for continuity and the problem was resolved.
I cut out the stencil for the solder paste today according to the instructions on the class blog though it took a few tries to get the right settings and sizes for the pads, and will try to solder mask at least one of two boards that I was able to get etched tomorrow.
I tried to apply a solder mask two separate times however for some reason it did not work, not sure why.
Picture of the board with parts mounted.