Raspberry Pi Power Monitor

The Raspberry Pi Power Monitor is a combination of custom hardware and software that will allow you to monitor your unique power situation in real time (<0.5 second intervals), including accurate consumption, generation, and net-production. The data are stored to a database and displayed in a Grafana dashboard for monitoring and reporting purposes.

This project is derived from and inspired by the resources located at https://learn.openenergymonitor.org.

What does it do?

This code accompanies DIY circuitry that supports monitoring of up to 6 current transformers and one AC voltage reading. The individual readings are then used in calculations to provide real data on consumption and generation, including the following key metrics:

Total home consumption
Total solar PV generation
Net home consumption
Net home generation
Total current, voltage, power, and power factor values
Individual current transformer readings
Harmonics inspection through a built in snapshot/plotting mechanism.

The code takes tens of thousands of samples per second, corrects for phase errors in the measurements, calculates the instantaneous power for the tens of thousands of sampled points, and uses the instantaneous power calculations to determine real power, apparent power, and power factor. This means the project is able to monitor any type of load, including reactive, capacitive, and resisitve loads.

Installation

These steps are for the Raspbian (Debian-based) operating system. I highly recommend using the "lite" version of Raspbian to avoid wasting resources on a GUI. Also, I have only tested this code on a Raspberry Pi 3b+. I would not recommend using an older Raspberry Pi.

In summary, the following steps will:

Update and upgrade your Pi
Install Python 3.7 & pip
Install Git
Install Nginx (optional, but recommended for viewing raw data - more on this in the project Wiki)
Install Docker
Download the InfluxDB and Grafana docker images
Download the source code for this project
Install the Python dependencies for the source code

You should assign a static IP address to your Pi and issue the following commands over an SSH connection. There are countless guides on the internet to do this... here is one.

Update and upgrade your system:

 sudo apt-get update && sudo apt-get upgrade

Install Python 3.7, Git, Pip, and Nginx:

 sudo apt-get install python3.7 python3-pip git nginx

Install Docker

 curl -fsSL https://get.docker.com -o get-docker.sh
 sudo sh get-docker.sh

Add the default Pi user to the docker group. If you are using a different username, replace Pi with your username:
```
 sudo usermod -aG docker pi
```
Enable the SPI interface on the Pi
```
 sudo raspi-config
```
Use the arrow keys and the Enter key to:
- Select "5 Interfacing Options"
- Select "P4 SPI"
- Enable the SPI interface
- Press Tab twice to move the selector to Finish
Modify the permissions of the webroot so that Python can write to it. If you're not using the pi username, be sure to change it before executing the commands below:
```
 sudo chown -R pi /var/www/html/
 sudo chgrp -R www-data /var/www/html/
 sudo chmod -R 750 /var/www/html/
```

Update the Nginx configuration to turn file indexing on, and remove the default Nginx index file:

 sudo nano /etc/nginx/sites-enabled/default

Find the section that looks like:

 location / {
          # First attempt to serve request as file, then
          # as directory, then fall back to displaying a 404.
          try_files $uri $uri/ =404;
          }

... and add autoindex on; underneath the try_files line. The block should look like this:

 location / {
          # First attempt to serve request as file, then
          # as directory, then fall back to displaying a 404.
          try_files $uri $uri/ =404;
          autoindex on;
          }

Close your text editor with Ctrl-x, then a "Y" to save the file. Then, remove the default index.html file:

 rm /var/www/html/index.nginx-debian.html

Reboot your Pi:
```
 sudo reboot 0
```

Download and run the Grafana and InfluxDB Docker images

 docker run -d --name grafana -p 3000:3000 grafana/grafana
 docker run -d --name influx -p 8086:8086 -v /opt/influxdb:/var/lib/influxdb influxdb

Run docker ps and confirm that the two docker containers are running. Here is what the output should look like. Your container IDs will be different, but the rest should be the same.

 pi@raspberrypi:~ $ docker ps
 CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                               NAMES
 013caaf13240        influxdb            "/entrypoint.sh infl…"   19 seconds ago      Up 16 seconds       0.0.0.0:8086->8086/tcp              influx
 8e763709b515        grafana/grafana     "/run.sh"                3 minutes ago       Up 3 minutes        3000/tcp, 0.0.0.0:3000->3000/tcp   grafana

Note: If you get a permission error when executing the docker ps command, make sure you entered the correct username in step #4 and that you have either logged out and back in, or simply rebooted your Pi.

Download the source code for this project

 git clone --single-branch -b master https://github.com/David00/rpi-power-monitor.git

Navigate into the rpi-power-monitor directory and install the Python library dependencies.
```
cd rpi-power-monitor
pip3 install -r requirements.txt 
```

Next Steps

Head to the project Wiki to get started on the rest of the setup process.

Credits

OpenEnergyMonitor and forum member Robert.Wall for guidance and support
The spidev project on PyPi for providing the interface to read an analog to digital converter

Like my project? Donations are welcome!

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