Analog solar power meter

Using the Rpi, i've built a system that reads the data from my SMA inverter, and shows live output to an analog meter from the 30's.

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High tech meets vintage, a super cool add-on for my home...

The idea came to me when we were redecorating the house, and I wanted to show our technology backgroud in a subtle way.. My wife and I are both engineers, we enjoy technology very much and are lucky enough to work with it every day.
A couple of months ago, we have installed our own 6500Wp solar system. I figured that it would be great to show the actual power output of this high-tech system on an antique, analogue meter, using the Raspberry Pi to interface between the SMA inverter and the analogue meter.

Since it was not available (as far as I know) on any online repository, I decided to create the scripts myself, using NOOBS and python as building blocks. It's my first Rpi project, hope you like it :)

Still working on the scripts, but when I get them finetuned and stable, I'm willing to share them here. Just let me know you're interrested.

I'll publish some pictures when it's presentable ;)

I'm using the hardware PWM output on the Pi to generate the 'analogue' output. Without any filtering, I'm directly feeding it to the analogue meter. As it turns out: 50% dutycycle actually means 50% output on the meter scale :)

Lucky me, the theory seems to work....

  • 1 × Raspberry Pi B+
  • 1 × Crompton Parkinson 15mA ammeter
  • 1 × SMA STL-5000 Solar Inverter
  • 1 × Software: SBFSpot For readout of SMA inverter

  • Scale adjustment

    Sander Los02/20/2015 at 21:01 0 comments

    now the Meyer is up and running, it's time to do something about the scale... Made a photograph, edited it using the Gimp, printed it to fit over the original :) See the result:

  • Fixed broken clamp

    Sander Los02/20/2015 at 10:03 0 comments

    The vintage meter I bought had a broken connector on the bottom (i knew that), so I replaced that today.

    I've also tested the meter, it works :) It's in remarkably good shape. Time to tweak the limits and scale of the meter...

  • Vintage meter found...

    Sander Los02/13/2015 at 20:21 0 comments

    I've just found a cool bakelite vintage meter (Crompton Parkinson 15mA) on a trading website. Bought it :)

    The Software is already running, the power output is now show on a (way too modern) analogue meter that I owned already. In the daytime, I'm showing the actual output power, in the night i'm switching to the total kwh for that day...

View all 3 project logs

  • 1
    Step 1

    Install you Raspberry Pi with NOOBS:

    NOOBS Download from

  • 2
    Step 2

    Install and configure SBFSpot for the logging of your SMA inverter

    SBFSpot installation on the Rpi

    Make sure that csv logging is enabled, since my python script uses these files.

  • 3
    Step 3

    Log in using ssh on the Pi

    Install the wiringpi2 library on the raspberry:

    sudo apt-get update
    sudo apt-get install python-dev python-pip
    sudo pip install wiringpi2

View all 9 instructions

Enjoy this project?



Conrad wrote 02/13/2015 at 21:02 point

This is a good idea, might have to make one of these myself! 


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