The former hardware gave more and more problems. They were Alecto WS-4000 components that really had served their time. A serious problem with the weather station was that the temperature sensor heated up too fast in the sun light. Attempts to solve the problem with a solar operated fan failed so far.
The MiSol weather station has a fancy design and – as most models nowadays – has the thermometer mounted more in the shade of the case. It appears to be equivalent to the outdoor unit of Fine Offset models WH2300 and HP1003 as well as to the Buienradar weerstation BR-1800. The documentation was promised to be delivered with the unit but it was absent. Scanning the web did not yield immediate success but after a while I found one other amateur that used the same outdoor unit. On his web site he describes most of the soft features of the station. Upon request he sent me some more. With these I got the unit hooked to a Raspberry Pi computer using an RS485-USB stick.
The unit contains no pressure sensor, so the Raspberry Pi was equipped with a BME280 mounted on a small breakout board. The software to control the outdoor unit and the pressure sensor was – after all specifications were figured out – relatively simple. Interfacing to the USB-connector uses standard commands and the pressure sensor was interfaced using WiringPi. It is now working for a few days without problems and it is feeding Weather Underground, KNMI-WOW and maybe in the future to other organizations. The widget on the left bar should connect to the weather data.