@mfalkvidd the 'local adc' library is the hx711 library which I placed in the sketch folder. Sorry for the confusion

@NeverDie @Nca78 a lot going on here Nice to see that my afternoon project sparked creativity.
I started this to be a datalogger for remote monitoring of MySensors node power consumption. During the run changed my mind and it turned out to be this which fits my needs. But all options are still open..
The converter has a max sample rate of 80Hz which was default on the board I used. I balanced accuracy and readability by applying sample averaging. This averages out much of the noise from USB source etc.
The sparkfun boards are probably designed a little different and don't have the shield which helps to keep out noise.
To increase speed you can change the amount of averaging (number of readings per sample)
To get a better response for the button the way is to go for non blocking (averaging) readings of the Adc. The library is very basic so that would be the best place to start.

@dakipro It would take a resistor and analog power reading to include basic power measurement. Current would vary between ~3mA and 70mA (with amplified radio).

@core_c Thanks, I missed that

@gohan I used a kit. There is also a description and suggestions on improvement of the "Chinese clones" in the documentation of the project.

@Yveaux I soldered the thing myself so build quality is .... The board I received looks to be solid as well as the components.
Accuracy in resistor/ capacitor meaurement is fine (~5% which is also the toleration of the components tested) Semiconductor analysis is enough for me with Fet / Junction transistors as I can determine the most important characteristics (including the pin layout!) which are within 10% of the datasheet. (pins are 100% correct :-))

@gohan said in Your workshop :

Aren't these devices basically Arduinos? It's written on the title atmega328. If so if we could get our hands on the code, we could make our own

I finally found the place where the Chinese get their code and design for the "Transistortester". It comes from a german site
a very extensive project. I doubt if I will ever be able to match or even comprehend what they accomplished.

@tailchopper I wonder if you wouldn't be better of on another forum. MySensors provides an infrastructure for home-automation and IoT. If you are not into connecting it to a MySensors ecosystem there are some dedicated PV (power monitoring) forums which probably give you more focussed / better answers. Like Openenergymonitor

@tailchopper It would depend on the output voltage & current of your PV panel. Up to 26V 3.2A the ina219 is a very convenient all-in-one sensor with I2C interface.