Table of contents
Introduction
One of the main goals of the circular food economy project is to incorporate digital technologies to both manage compost and provide the participants with an incentive to take part.
This page is intended to be an overview of the role technology takes in the project; later pages in this category will provide more technical knowledge to allow those with the expertise to replicate what we have done for their own projects.
The following is covered on this page:
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How digital technology can support a circular food economy;
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The general features of the mobile app and other supporting software;
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The sensor system that is used to keep track of the state of the compost; and
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How all of the technology used here is connected together via the Internet of Things.
To assist in replicating this project in other locations, the source code for the app and all the plans for constructing the sensors will be made available for free, with a permissive license.
Role of digital technology
Digital technology is intended to contribute to the project in several ways: by giving participants – in YSSC’s case, the students – knowledge about compost, to incentivise them to take part, and to give them tools to manage the compost.
The mobile app – developed by QUT researchers – covers the first two aspects. Developed for use on all types of mobile device, it provides a variety of features. It provides information about compost – why we wish to produce it, what it is, and how it’s produced and used. For YSSC, a quiz is also included for the students to test their knowledge.
To give the students a reason to take part in the project, they can also score house points when they bring their food scraps in from home. So that they know how well their house is going, students can access the current house points right from the app.
For other sites and new projects – there is potential to piggyback on existing databases to include incentivisation and rewards data.
A specially designed sensor system – developed by Substation33 – is used for monitoring the compost bins. In YSSC’s case, this provides a hands-on experimental method to support student learning in proactively managing a natural system. These sensors are intended to be part of the circular economy as well, as they are constructed mostly from parts from discarded electronics and other recycled materials.
These sensors can measure the temperature, humidity and methane levels in a compost heap, and this information can then be viewed in the mobile app. In particular, the methane levels can be used to determine if the compost heap is becoming anaerobic by producing too much of this greenhouse gas. For the students, it can be used to educate on proper management of the compost and how to prevent this condition (by adding carbon such as brown leaves, twigs, and cardboard egg boxes). More details of the sensors can be found below.
Another aspect of technology that is specific to the school is loaning out and keeping track of the “compost caddies” that the students are using. Students are allowed to take home small buckets, fill them with waste food and other scraps, and bring them back to school for adding to the compost heap, as well as being rewarded with house points. These buckets were added to the cloud library database system that YSSC uses to track books, based on the suggestion of one of the students that we could “track caddies like library books, using a scanner”.
Mobile app
As part of the circular economy classes and scheme at Yarrabilba State Secondary College, we have developed a companion mobile app. Named Yarrabilba SSC Compost and available on both the Apple App Store and Google Play Store, it shows information about the scheme and composting, as well as facilitating incentives for the students to take part.
The main features of the mobile app include:
- screens showing information regarding the scheme at YSSC, as well as an overview of what compost is, how it is made, and – most importantly for the scheme – what materials can be composted. This information is shown in text, picture and video formats.
- a screen that displays the current house scores. These scores are based on the scraps students are bringing in: the more often a student brings in scraps, the more points their house gets.
- a screen that shows the latest data from sensors (developed by Substation33) in the compost bin. This is to both increase student interest and to encourage them take more responsibility for the compost by letting them monitor it.
- a quiz that shows five questions randomly from a large selection, and shows how many were answered right or wrong once all have been completed. This is used to test the students’ knowledge.
The galley below shows some of the screens of the mobile app. You can click on them to zoom in and see the full image.
The mobile app also can connect to its own back-end server. This is where the house points and sensor data are stored. It also includes a website where an IT administrator or staff member can use to manage the data for the app. This website is also accessible to anyone to view information on the project at the school (but not the management functions). The app does not need this server to function, only to show the house points and sensor data, so the other functions of the app will still work.
While this app (and its back-end server) are specifically designed for YSSC and the systems used by the sensors, we have provided the resources to modify it for use for other schools and organisations on the Mobile app page.
Sensors
The sensor system that was created by Substation33 for the project at YSSC is designed to measure various characteristics of the compost heap, such as the methane, moisture and temperature levels. This is to keep track of the decomposing materials and ensure there are no issues, such as an improper mix of materials causing too much methane to build up.
The main component that drives the sensor system is an Arduino microcontroller, a small and cheap device that can be freely programmed for many different uses, and can connect to various external components such as the temperature, humidity and methane sensors used in Substation33’s design. It has an mobile Internet connection and uploads the data from those sensors to the Internet of Things (in this case, the ThingsBoard platform).
In the spirit of the project, the sensor system also consists of several components that are recycled from both regular waste and e-waste. The main component of e-waste is the battery pack. Laptop batteries are one of the items that is often disposed of at Substation33 (usually coming with the laptop itself), and usually it is only a few cells out of the whole pack that is faulty. As this sensor system was intended for use away from a plug, the sensor uses a pack of recycled laptop battery cells that can be recharged via solar panel.
Other recycled parts used in the construction of the sensors include the USB cables converted for use in connecting up the sensors to the Arduino microcontroller, as well as an old PVC pipe to make the exterior housing for the main sensor system. However, if you do not have e-waste available or the expertise to recycle it, off-the-shelf components can be used.
The below videos show how the sensor system can be constructed and the parts required. The Sensors page shows the configuration of the sensors in more depth for those that wish to recreate a similar system for their own project.
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Part 1 – The Sensor Tower |
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Part 2 – The Methane Sensor |
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Part 3 – The Moisture Sensor |
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Part 4 – The Water Level Sensor |
Connecting to the Internet of Things
While the mobile app does not need any type of connection to show information on the circular food economy scheme and compost, it is intended to connect to the Internet in order to show data: in this case, sensor readings and house scores. The main interaction with the Internet of Things is with the sensor system, though it was also intended to incorporate the tracking of compost caddies.
Sensor data
Every 30 minutes, Substation33’s compost sensors transmit data (methane levels, temperature, etc.) via mobile internet to a cloud service for storing data. In this case, this is the ThingsBoard platform, though an alternate service can be used assuming the sensor is configured to do so. These cloud services provide the ability for other applications – such as the mobile app – to access the data stored on them.
The mobile app has a back-end server which connects to the cloud service and is sent the new data when it arrives, which is then stored on the server. The mobile app can connect to the server at any time and download the latest sensor data.
While there has been only one sensor active at YSSC at this point, the mobile app can read data from multiple sensors once they are installed.
Caddies and house scores
As part of the circular economy scheme at YSSC, students are encouraged to borrow a compost caddy and take it home to fill it with scraps. They then bring it back into the school in order to gain house points.
The school makes use of a cloud-based library database system – in this case, the Oliver system. The compost caddies have been added to this system and so which student has borrowed which compost caddy can be tracked.
It was intended to add the capability to automatically update house points when the students brought in their caddy (assuming it contained food scraps), as well as show a notification if a caddy was missing. Unfortunately, unlike with the cloud data service, there is no capability to connect and automatically retrieve data on caddy loans and returns with Oliver, as far as we know.
Staff can therefore connect to the mobile app’s back-end server and update the house points manually when they need changing. The server also has the capability of reading a file downloaded from the library database system in order to suggest additional points to the houses based on returned caddies. These points can be shown on the mobile app at any time.
Activities
Watch/discuss the contents of the app
Objective: Understanding of waste types and their origin; think about how to present useful instructions and other contents for mobile phone apps, understand how to improve the user experience of apps.
- Download the mobile app explore and engage with the contents individually or together as a group exercise. Different students or groups may also focus on different sections of the app.
- Discuss the rationale for different instructions and come up with examples and ideas of how to add more content and examples. What problems is the app trying to solve? Can the solutions be improved?
- Discuss what meaningful instructions look like and how to make sure they work.
- Complete the compost quiz individually or as a group – maybe even as a competition between groups.
During a compost app feed-back session with students lots of interesting ideas were spontaneously presented after the students had engaged with the latest release of the App. For example, as one important problem we discussed how to organise the scanning of compost buckets, which is an essential function to monitor incentives and competition (e.g. for house points or tuck shop credits). One student idea presented proposed to treat buckets like library books, issue the same barcodes and scan buckets in & out using the library system. A very spontaneous, simple solution using existing resources! No doubt, young genius at work.
Click on the photos below to zoom in.
Workshop to disassemble hard-ware and recover e-waste for further use
Objective: Understanding of the e-waste problem and how to recover and re-use e-waste parts to build sensors or other devices; practical hands-on activity.
This activity is fun but must not be done without expert supervision as some of the parts should not be dismantled without appropriate guidance (e.g. laptop batteries). Our partner Substation 33 delivered this workshop at the school at a workshop room. Several containers filled with computers and e-waste including the necessary tools were made available to students and they dismantled parts in small groups around working tables. Each table was supervised by one expert.
E-waste dismantling proved one of the most enjoyable activities of the program and became a real highlight of the year, in terms of the activity itself as well as the focused engagement and learning. The e-waste workshops never saw anybody getting bored.
Excursion to e-waste social enterprise (Substation33, Queensland)
Objective: get a first-hand impression of the operation of an e-waste recycling shop, including more sophisticated equipment and processes.
This activity was another highlight as it combined the e-waste workshop with an excursion into an entirely new world. The students had a brief workshop tour and then settled into different tasks in groups. They learned about e-waste by digging through piles of discarded equipment dropped off into skips, and they were of course able to disassemble some parts themselves. Beyond what the school e-waste workshop was able to achieve, the students learned about the creative aspects of e-waste recovery, how to put the parts back to use. They were for example introduced to a 3D printer (itself made from e-waste parts), the e-waste mobile coffee cart and screens filled with data which were gathered and transmitted using e-waste sensors in different locations.
The excursion concluded with a BBQ lunch shared with all staff at Substation33.
