some people may know my "TinyTOSLINK" addon for the classic rev. B board:
http://www.raspberrypi.org/forums/viewt ... 45&t=75225
(optical audio output, optional S/PDIF output and input)
I now have created a B+ variant. It is larger, because the required pins are all over the connector. But it still is a relatively small strip of PCB, can be installed without soldering.
Logically it can be a HAT, because I added a footprint for the ID EEPROM. Mechanically it isn't, because I wanted all to fit in a normal case, no buildup for an extra board ontop. The TOSLINK transmitter is mounted downwards, to not add height. Like with my other board, it could be mounted "deep" and soldered directly to the header, the transmitter on the top side. But I guess since plugging with 40 pins is quite rigid and needs no soldering, nobody will go for that with B+.
I chose a smaller transmitter this time, to leave more room for the LEDs underneath. And it has 25 MHz bandwidth, which is needed to transmit 192 kHz sample rate audio. Until recently, I didn't know such is possible for TOSLINK, thought it would require S/PDIF. The receiver needs to be capable, too, which had a ripple effect in my household, replacing switchbox and DAC input receivers...
However, these components are hard to find, I ordered them from china.
Finally, some pictures, click them to enlarge:



I can build some of these, for people who appreciate my work and have good use for it. Before doing so, I need to find a source for the 40 pin connector with a reasonable price.
So long,
Jörg
Jörg