The Raspberry Pi.

Abstract

The purpose of this project is to present logged data from the CCAT house solar panels at Humboldt State University onto a website in real-time.

Background

The Campus Center for Appropriate Technologies (CCAT) house at Humboldt State University in Arcata, California has a variety of solar powered projects on site. Our (Engr305 Appropriate Technology) project for the Spring 2014 semester is to provide CCAT with a data logging system that will track the voltage generated by the photovoltaic (PV) panels on the roof of the CCAT house, and upload that information onto their website. CCAT has asked that we create a real-time energy monitoring system for the PV panels on the roof of the CCAT house. The information that has been tracked by these PV panels must be accessible to all users on the internet through the CCAT or Appropedia website in a simple, easy-to-read manner.


Problem statement

The objective of this project is to develop a data monitoring system to capture the electricity generation from the photovoltaic panels located on the rooftop of the CCAT house at Humboldt State University and display the data online in kWh's. This will be accomplished by researching and determining the best software and hardware to install, allowing CCAT officials to store the solar power data and access it at any time. Ideally, with open-source software and affordable hardware that will allow any one to access the information online. The data will be displayed on the CCAT websitein easy-to-read graphs and will continuously log the data throughout the lifetime of the system.

Criteria

The goal of this project is to install PV monitoring hardware and software at the CCAT house located at Humboldt State University. The data must be uploaded to the CCAT website and be available 24/7 to anyone interested.

Criteria Weight
(1-10)
Accessibility Solar data from CCAT must be streamed online in kWh, and must be accessible to any one online
10
Education Factor Historically logged data must be easily accessible and formatted in such a way that students can use the data for future projects, assessments, etc.
10
Low maintenance Solar controls must automatically upload information to the CCAT or Appropedia website to display logged solar data
9
Budget Must not exceed budget of $1,000
9
Real time data Data must be graphically represented on the CCAT or Appropedia website, and updated at least twice per day, and at most, in real-time
8
Ease of use Graphical representations of data must be easy to follow, and software must be easy for CCAT co-directors to navigate, if necessary
7
Aesthetics Graphs must be pleasing to the eye, look professional, and be easy to read
5

Literature Review

Many Residential Solar Data Collection and Monitoring design options were reviewed during the research and development process.

Electronic Data Logging

This general term is defined as an electronic device that records data over time. It can be built-in to a system to receive readings off of a sensor or directly from the data source. Small processors that collect the data, utilize computer software, and display the data with either a direct LCD screen or transfer the data to an alternative storage device, such as the world-wide-web. One of the primary benefits of using a data logger is the ability to collect live data automatically in real-time, continuously throughout the day. Once activated, data loggers do not require human maintenance; they can be left unattended and continue to successfully log information.

Current PV System

Currently, the CCAT house has 8 PV panels on the rooftop of the main house. These panels are the same ones that were generously donated by ASE Americas back in 2001, and remounted onto the rooftop when CCAT moved locations in 2008. The Inverter Currently Installed at CCAT is a Magnetek Aurora 3600-US-OUT. The company Magnetek has since been bought by Power-One. The Power-One Aurora 3600-US-OUT installation manual can be found here.

The Wiring diagram (below) is from 2014, and is an accurate record of the current system. CCATPV2014.png

For more information on the [CCAT] PV System as of 2014, visit the updated CCAT_PV_system Appropedia page.



The 8 solar panels on the rooftop are wired together in 2 strings of 4, mainly because the panels were previously hooked up to two separate inverters. Since there is only one inverter, both strings of the 4 solar panels had to be wired together in series, and hooked up to the one updated inverter through the "PV Input 1" port on the Magnetek Aurora inverter. Instead of re-wiring the panels on the rooftop when replacing the two old inverters with the most current Magnetek Aurora inverter, Solar Roger, the local solar electrician/installer, decided to just splice these wires together. This way, the 2 strings of 4 solar panels wired separately on the rooftop are merged together in series, into one continuous string, connected to the input of the one Magnetek Aurora inverter.

The current CCAT Photovoltaic system is shown below through images of the DC disconnect box, the box of wires below the inverter, and the Magnetek Aurora inverter.

Construction

Time Table of Tasks

Task Week completed
Research Week 07, Friday, 03/07/14
Shopping Week 08, Friday, 03/14/14
Learning Raspberry Pi Week 10, Friday, 03/28/14
Programming microSD card for Raspberry Pi Week 13, Friday, 04/18/14
Installation and Testing Week 15, Friday, 05/02/14
Create YouTube Video Week 16, Friday, 05/09/14
Finalize Appropedia page Week 16, Friday, 05/09/14
Showcase final product to CCAT and ENGR 305 class Week 17, Monday, 05/12/14
Project Completed Friday, May 16, 2014

Costs

Quantity Material Source Cost ($) Total ($)
1 Raspberry Pi Amazon.Com- Raspberry Pi (free shipping) 39.00 39.00
1 Raspberry Pi Case Amazon.com- Raspberry Pi Case (free shipping) 9.00 9.00
1 RS485 to USB cable Mouser.com 42.50 +shipping 49.49
1 Micro USB to USB power cable RadioShack 21.64 21.64
1 5V USB Power Adapter ebay.com- USB power adapter 5.00 Donated
1 Ethernet cable 25' HSU Information Technology Services 20.00 Donated
1 SD Card 8GB Best Buy 10.00 Donated
1 HDMI to HDMI cable (used for set-up) Amazon.com 10.00 Donated
1 HDMI compatible monitor (used for set-up) Newegg.com 100.00 Donated
1 Computer Mouse (used for set-up) CDW.com 10.00 Donated
1 Keyboard (used for set-up) Monoprice.com 10.00 Donated
Total Cost $97.49

Operation

Maintenance

The brilliant part about the Raspberry Pi is that once it is programmed and set up initially by this project team, there is no need for any future tinkering with the device or its' components. CCAT Co-Directors can simply log onto the internet and view the live-stream energy data from the website. The Raspberry Pi itself is stored in the downstairs storage closet next to the inverter. As long as the power is plugged in, the device will need no maintenance.

Project Design

The cheapest, most versatile option for this design is to connect directly to the inverter through its' RS485 connection. Currently, the Magnetek Aurora inverter has data logging capabilities and can translate that data to Aurora Monitoring software. That monitoring software presents the electricity generation data graphically in real-time, but it is bound to a local computer only. Using a Raspberry Pi, this data can be sent to the internet using open-source codes.

CCAT PV Monitoring Design using the Raspberry Pi hooked up directly to the Aurora Inverter via RS485 connection. The keyboard, mouse, and monitor are only needed for initial setup and programming.

Components

This design incorporates a Raspberry Pi, a USB to RS485 cable, an ethernet cable, microUSB power cord, and a MicroSD card.

The Raspberry Pi is a wallet-sized computer that was developed in the UK as a tool for children to learn computer programming. It is compatible with many operating systems such as Python, Raspbian, Linux, and many more for the beginner to advanced level computer programmer. You can run word processing and spreadsheets just like a laptop computer, as well as watch High Definintion television through its' HDMI port and audio outputs. It is not limited by its physical components, as you can solder other parts to the device, and connect through its' 26 dedicated GPIO pins, which can be infinitely expanded upon. Raspberry Pi.png


The RS485 to USB cable transfers the logged data from the Magnetek Aurora inverter to the Raspberry Pi. The Raspberry Pi is a small computer that requires an SD card encoded with an operating system; we used Raspbian with an 8GB SD card. The SD card that runs Raspbian is also encoded with Aurora open source forge software that displays the inverters' logged solar power data online. It is sent through the Raspberry Pi network plug to the Local Area Network (LAN) connection located in the CCAT house. Eventually, we will have HSU's Telecommunications crew install a LAN connection in the downstairs storage closet where the inverter and Raspberry Pi will reside.


Once the data from the inverter is sent to the internet via LAN, open-source software translates the Aurora monitoring data onto a website called PVoutput.org. This website graphically shows how much electricity is being generated by CCAT's PV system in 5-minute intervals.

This design option costs no more than $100 to implement, and is an excellent demonstration of the abilities of open-source software to provide a community with PV data monitoring.

Replication

For those of you who wish to replicate this project:
This hardware is ideal for a multitude of projects, ranging from programming robots, to data collection. This software is specifically meant for this Aurora inverter, and will not benefit any other projects, unless they are running Aurora Monitoring software directly through an Aurora inverter. For replications of this project with other inverters, research will be necessary to find the right open-source software for your needs.




Project goals

Our goals:

  1. Learn about the CCAT PV system
  2. Research the best monitoring design for this system
  3. Learn about the Raspberry Pi and the Raspbian operating system
  4. Research and determine the best open-source software for the Raspberry Pi
  5. Learn how to program the Raspberry Pi with open-source software
  6. Get project idea approved by Information Technology Services (ITS) at Humboldt State University
  7. Get project approved by CCAT Co-Directors, CCAT Key Advisor, and HSU's Director of Sustainability
  8. Get the kWh data from the Aurora Inverter to the world-wide-web
  9. Embed the Aurora Monitoring Program code onto the CCAT website

Instructions

We used a Mac Computer with an OS X Operating system for all the following steps.

Part 1: Installing NOOBS Software onto SD Card Software

If you are starting from scratch, follow these instructions to install NOOBS onto your 8GB or larger SD card.

However, to save 40 minutes of your time, it is highly recommended to purchase a pre-loaded SD card from a trusted online distributor, such as Amazon.com.

If you are starting with a pre-loaded NOOBS SD Card, skip to Part 2 below.

File:Reach-out92.jpg
How to Format your SD Card and Install NOOBS

Part 2: Installing SourceForge.net Aurora Monitor to the SD Card

File:PiDesktop-300x157.jpg
How to Install Aurora Monitoring Open-Source Software Onto SD Card

Part 3: Raspberry Pi Hardware Setup

File:Pi2.JPG
How do I set-up the Raspberry Pi Hardware?

Part 4: Formatting Raspberry Pi

After each

command line

hit ENTER on the keyboard to complete each command.

File:Lxterminal.png
How to format your Raspberry Pi with fully loaded SD card

Part 5: Configure Aurora Monitor Settings

File:Part 5 Configure Aurora Monitor Settings.pdf
How to Finalize Raspberry Pi Aurora Monitor Software

Conclusion

Testing Results

The testing was all done after our programming was initially proven successful. Therefore, the results of our physical testing were successful. Programming the Raspberry Pi was broken up into 3 separate working sessions. The first part of testing went well up to the point of programming the SD card with the Raspbian image and Aurora Monitor sourceforge.net software.

The second part required minor adjustments to the open-source instructions to best fit our project needs. We received help from Roger Tuan, a former CCAT Co-Director, to make sure we were on the right track with changing the codes. The code changes included: setting up an IP address for the Raspberry Pi as well as filtering out a couple type-o's in the open-source code.

The third round of testing was a dry run hooking up the inverter to the Raspberry Pi and the LAN connection. We had to work with Telecom to get a MAC address of the Raspberry Pi approved before being able to connect to the Humboldt State University network. We also had to set a temporary IP address for internet connection to the Raspberry Pi because at this time it does not have its' own LAN connection in the CCAT house, it is just borrowing a LAN connection from the CCAT library computer.

We drafted a test page for the CCAT website, with the help of Roger Tuan, embedding the pvoutput.org graphs onto a /PV link on ccathsu.com.

After all testing was completed, the project is deemed successful. As soon as the LAN connection is installed near the inverter, the results will be continuously streamed live on the pvoutput.org website and the ccathsu.com/pv website and pvoutput.org user id=31570.

We were able to receive real-time data displaying the Watts, Volts, Amps, kW, and kWh data. The data is updated onto the website every 5 minutes.

The image below is a screenshot of the PVoutput.org website, showing our testing results. Once the LAN connection is installed, this data will be streaming lifetime data, and will be stored on the website for the life of the system.

Screen shot 2014-05-11 at 9.19.55 PM.png

Discussion

With 3 design changes, we learned a lot about the University requirements, the CCAT PV system, and how many different software programs and components work together to log energy generation data and monitor that data online.

Lessons Learned

  • Do not rely on any one's information regarding crucial information on an old system such as the one at CCAT. Do your own research, and reach out as much as possible to multiple people from different social layers within the community.
  • It would have been nice to purchase an SD card that was pre-installed with the NOOBS software, as it was the same cost of a normal 8GB SD card, and it saved a lot of time and effort.
  • To avoid dependency on corporations, go directly to open-source software in the beginning stages of a project such as this. Open forums are surprisingly informative, and the writers and users are eager to help, especially if it means talking about their own projects!
  • ITS at HSU requires approval for any wireless router to be installed on campus. If the frequency of the wireless signal is 2.4 Ghz or between 5.0 to 5.7 Ghz, the request will automatically be denied, as it will interfere with the IT system on campus. Most of the wireless routers we found to transfer local data information to a web server were around 433 Mhz, like the Efergy Energy Monitor for example, and are "good to go", according to ITS.

Troubleshooting

For any issues with the above instructions, programming the Raspberry Pi, or experiences with glitches in the CCAT system in the future, please refer to the following:

  • This website was used to download the Aurora Monitor software that is displayed through the Raspberry Pi to a local monitor on-site.

Aurora open-source-forge website

  • This website was used to follow instructions for the bulk of our project. We did change a few details such as: omitted most of Part 2 and this project used a wired connection instead of Wi-Fi.

Project Page: Open Source Hardware and Software Resource for Aurora Monitor, Raspberry Pi, and PVoutput.org Setup

  • Contact Us!

References


Contact details

  • Nicholas Colbrunn nrc190@humboldt.edu.
  • Jenna Bader jlb272@humboldt.edu
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