A little bit of progress

Today I found some time to do a little soldering.

I needed to add an audio amplifier to drive a speaker, so I don’t need to use headphones all the time. This was not needed when I used computers as frontend, but now I have decided to use the Raspberry PI this became an issue. With the Raspberry, I use two external USB sound cards, one to interface the Lima SDR, the other to interface me, i.e. a headphone / speaker and a microphone. The sound card for the Lima is the Behringer, which I described a few posts back, for the sound/mike I have bought a cheap USB unit, the soundlink UA0078. It is plug and play under Raspian, so that was an easy addition. But it is not powerful enough to drive a speaker directly, hence an amplifier is needed

I decided to use a kit by Velleman, which you can buy for less than ā‚¬10,00 at Reichelt. This delivers 4W RMS, 7W peak, so that must be more than powerful enough.

There was some space left on the PCB with the Arduino controller, so I mounted it there.

After finishing that, I continued with finalizing the interface wiring to the Lima SDR and the small TFT screen. And it works, so I did not make large mistakes while transferring the design from the breadboard to the PCB. šŸ˜‰
The picture below shows how it looks now. Note that the display is not nicely aligned, this is because it was just temporarilly mounted. I have to properly fix it with some glue and tape (there are no mounting holes on the TFT).