simple breadboard adapter for cheap BLK-MD-SPK-B module from ebay based on OVC3860 with 3.5mm jack for headphones, microphone and buttons.
video (ver. 1.0): https://www.youtube.com/watch?v=mN-LFUUrpa8
boards are for sale(or kit, whole product...), contact me if you are interested, or buy on tindie:
top view, assembled unit
bottom view, assembled unit, with BT module soldered (silk screen marking of C3/R4 was switched, fix with perm. marker)
assembly plan (fixed silk screen):