Return to Ritherdon Project

Light-Meter

Disclosure: This file was written by Craig Oates and all information cited about other parties where taken from their respective websites. I have, also, applied minor editing in places to help readability - in the context of this file. Please use the links listed for original/official version of the sourced material. Craig is the author of the software in this repository.

Project Overview: Return to Ritherdon

"Return to Ritherdon" is a two year residency at Ritherdon & Co Ltd, a manufacturer of metal enclosures based in Darwen, Lancashire U.K. It was devised by artist Nicola Ellis and funded by Arts Council England.

• Nicola Ellis
• Ritherdon
• Arts Council England

About the Artist: Nicola Ellis

Nicola is interested in the properties, value, function and circulation of materials. She has a current focus on metals and the companies that work with them, her work draws on the visual and spoken language of industry operations, fabrication and profiling processes. The parameters for her sculpture, installation, drawings and videos include relationships between people, businesses and technology.

About the Manufacturer: Ritherdon

Established in 1895, they have been manufacturing a variety of electrical enclosures and related products for many decades. A combination of a passion for innovation with close working relationships with their customers means that they are continually developing and expanding their product ranges.

About: Arts Council England

They were set up in 1946, by Royal Charter, to champion and develop art and culture across the country. They are governed by an Executive Board and National and Area Councils.

• Arts Council England's Royal Charter

Project Overview: "Unnamed at time of writing"

This project is one of several artworks created by Nicola Ellis throughout the course of the residency. For the sake of brevity, this file will focus on the technical aspects of the project. The same is true for all files in the repository.

The overall project consists of three separate/smaller projects. The names of the smaller projects are a by-product of the software development process. You should not view them as individual pieces within the overall project. From an artwork point-of-view, "UNNAMED ART WORK" is one piece. The name of the software projects are "light-meter" (which is this one), "mid-point" and "relay". All three projects reside in their own git repositories. You can find the other project's repositories are the following links:

• Mid-Point
• Relay

The (technical) aim of the project is to turn a set of lights on the gallery when welding machines are active in the welding booths in Ritherdon. The solution we arrived at was a three-stage process. The stages are as follows:

1. Monitor the light levels in the welding booths at Ritherdon and send that information to a sever.
2. Receive the light readings and store them in a database and make them available for others to access.
3. Have the lights installed at the gallery connected to wi-fi enabled relays which request the latest light readings from the server. If the readings are above a certain threshold, have the light in the gallery turn on (otherwise, turn off).

For more information on how each project accomplishes its task, please use the (repo.) links above. Otherwise, here is an diagram to help explain the three stages mentioned above.

Project Overview: Light-Meter

This is a Python 3 based project. I wrote the code in this repository to run on a Raspberry Pi in a unmanned capacity. The main machine I tested the code on was a Raspberry Pi 4 (2 G.B.) but I did get it to work on a Raspberry Pi 1 (Model B) so do with that what you will. Software-wise, I have only used Raspbian Buster throughout the development of this project. So, I do not know how well this will run on other Linux-based operating systems. I must stress, this is a Linux-only endeavour. This will not work on Mac OS and Windows -- that includes Windows Subsystem for Linux (W.S.L. 1 and 2).

For the final version (exhibition context), I focused my efforts of running this project on Raspbian Buster Lite. That is the version of Raspbian without a (desktop) G.U.I.

The full list of parts this project requires is as follows:

• Raspbian
• Raspberry Pi 4(I am assuming you have the appropriate power cable, S.D. cards Etc.)
• 2 x 1kΩ Resistor
• 330nF Capacitor
• Breadboard(Optional but recommended if you do not know how-to solder or you don't feel comfortable doing it)
• Jumper Wires(I'm assuming you are using the breadboard. If are not, you might need different cables like Female-to-Female or ones without a connector on the end)

Hardware Preparations

This section has not been written...

Software Preparations

Depending on what version of Linux/Raspbian you are running, you might need to install some dependencies. I have listed the common ones I came across whilst developing this project. But, you might need to rely on your own cunning to track down missing dependencies.

# Don't forget to apt update and upgrade first...
sudo apt install python3-pip

sudo pip3 install requests
sudo pip3 install RPi.GPIO

# You might need to install RPi.GPIO via apt
sudo apt install python3-rpi.gpio

# I will explain why this is here below...
mkdir ~/repos

Note: I decided not to create/use a (Python) virtual environment because of the projects objectives. I expect the software in this repository to run on an unmanned machine with only one task to complete. The environment this project will run in/on will not change throughout the course of the exhibition. So, the redundancies afforded by the virtual environment are not needed.

When you clone this repository, you need to make sure you clone it into the following location: /home/rtrp/repos/light-meter/. From there, run the following command,

# This must be the first thing you run after you have cloned
# the repository.
. ~/repos/light-meter/make-log-files.sh

You can test the code is working properly by running it. You can do that by entering sudo python3 ~/repos/light-meter/cli_meter.py into the console. This is assuming the server specified in "cli_meter.py" is set-up and working as intended.

Note: For some reason, I had trouble running "cli_meter.py" without sudo. I would sometimes get an error message saying "RPi.GPIO is not available/installed" (paraphrased). If you manage to get it working without the use of sudo, remain as you were. Otherwise, keep a mental note of this if you come across the problem.

When you are ready to run this project as intended, you can set-up a cron-job for it. To do so enter sudo crontab -e into the console. You might need to select an editor if this is your first time setting up a cron-job. I tend to go for Nano -- which is option "1" most of the time. When the crontab file opens, enter the following commands at the bottom of the file,

@reboot bash /home/rtrp/repos/light-meter/startup.sh &
00 18 * * * /home/rtrp/repos/light-meter/shutdown.sh

These tasks make the Raspberry Pi send a message to the sever to indicate the status ("on" or "off") and makes the "cli_meter.py" script run. At this point, you should be able to walk away and let the Pi do its thing. This is assuming the server is up and running and the Pi is connected to the world-wide-web. If all is successful, you will notice the Pi will turn itself off at 18:00 (6 p.m.) and will start sending light reading when you turn it own with out no input from you. Unfortunately, the Pi can only manage the shutdown on its own. You will need to turn it on.

To make sure the Pi send a "powering down" message to the server, I tend you create an alias called powerdown. When you type this is, it runs the "shutdown.sh" script -- which has the shutdown command within it. To make the alias permanent, enter alias='~/.repos/light-meter/shutdown.sh' into ~/.bashrc.