Made good progress tonight with the client and server apps. Added the socket connection and SensorReading object to hold the sensor readings (surprise).
Adding work to rpi_client from this weekend.
I'm finally starting to put all the pieces together and build the RPI client. So far so good, although I still need to work a few details. I also reorganized my "test scripts" into a proper library so that I can call the relevant code from my client program.