Introduction

For this fortnight 3 homework, we were asked to write a concise report and document an experiment on our refrigerator system and any conclusions based on evidence that we collected during the experiment. I aimed to see how the refrigerator’s temperatures have changed over time with the influence of external conditions such as the refrigerator volume and the frequency of door opening compared to the outside room temperature.

The Process

Using the Circuit Playground Express (CPE) from Adafruit for the first time was exciting as the colourful LED lighten up when we plug it into the laptop to set up. The CPE can measure and record the temperature over a set time and the number of readings that I can set/program using the Mu Editor application. It was also my first time using Mu Editor, so I need to learn how to program the code for the CPE and familiarise myself with the Mu Editor capabilities.

Temperatures were recorded at the refrigerator compartment’s middle level using a Circuit Playground Express (CPE). The main sample refrigerators were on average 6.5 °C, a minimum of 4.5 °C and a maximum of 8.6 °C. I found that the temperature fluctuated inside the fridge and seemed dependent on the external condition that I experimented with. This report shows the influence of external conditions on the temperature.

I had few challenges in completing this homework because it was Easter long weekend, and I went back to Sydney to see my children and husband. So, I analyse two different fridges conditions hence why the results were varied. Also, I had to use the 3rd CPE devices because the first 2 CPEs didn’t work for me (keep rebooting/resetting to factory mode). Johan helped me to erase everything and set up fresh again, and it finally worked again.

The temperature difference between the readings during weekdays and weekends is not significant. Comparing temperature measured using a circuit playground express for every second for 30 minutes and every 10 minutes over two days shows no relationship between these two temperatures. This could mean that the temperature measured using the circuit playground express does not represent the refrigerator’s proper operating conditions. When the temperature data are analysed for all refrigerators without distinguishing the external condition, the mean temperature is 6.5 °C. However, when the analysis was performed considering the external condition, the mean temperature was varied for each condition. Sydney has a higher room temperature than Canberra, which influences the CPE reading slightly higher for my bigger refrigerator in Sydney than my mini refrigerator in Canberra.

My research shows that the combination of the external conditions (desired temperature setting, volume of the food, frequency of door openings) seems to have a valid impact on the refrigerator temperature. Furthermore, temperature impact on the growth of microorganisms and food waste or using a different device to measure the other parameters, such as organising the refrigerator compartment to optimise the power consumption and food preservation, can be exciting topics to research in the future.

The complete report can be found on the PDF link below.

Reflection

My belief and attitude in completing this fortnight 3 homework are still the same as per fortnight 1 and 2 homework’s that I will try to do my best in any way I could despite any challenges arisen. And if I face any technical challenges, I will ask the expert who knows how to solve my issues after trying to solve them first. Know who, when and how to ask is crucial and may inform my skill development in the future. Looking at my reflection on the first two fortnights, I can see the difference in my observation of my learning and skills improvement. Each fortnight, I learn new tools, programs, systems (CPE and Mu Editor) and apply the knowledge that I acquired on the previous fortnights, python. And I’m slowly making the reflective practice as my ongoing habit for each fortnight, which again I think is a good habit to have in my learning journey as a cyberneticist and NBE practitioner in future.

Acknowledgement

Thank you to Chloe for lending me her CPE that she used (the 3rd CPE that I tried), and to Johan and Mina, for helping me solved the CPE reset issue. Johan found out that I didn’t have any space left in my CPE. Apparently, I have too much reading data from the previous weekend readings that I used up all the 2 MB of SPI Flash storage as I didn’t delete anything and kept saving them all each time. So, I had to save the existing files first, rename and save them in a different location/folder. Then, delete the data on the CPE excel file to have enough space for the subsequent readings. This seems to solve the reset issue, and I can carry on with the rest of the experiments.