Close up of the Arduino mega board with some pins attached.
Picture of all the components before they were soldered together.
All the components for the project. Dial: Encoder, Item with 2 blue boxes: Relay, Long white wire: thermocouple, and an LCD screen.
The LCD screen showing the current and target temperature inside the oven. Relay lit up with LED to heat up the oven!
The problem we attempted to solve was regarding how healthcare workers and the general population have had more and more difficulty with purchasing face masks to combat the pandemic. We went about solving this health issue by having our project focus on finding a way to reuse face masks after disinfection.
What it does
We addressed this issue by modifying a cheap stock toaster oven to be repurposed as a mask sterilizer with precise temperature control. This was accomplished by implementing an Arduino based control with a proportional–integral–derivative (PID) controller and a thermocouple to track the temperature inside the oven to provide information for the controller and display.
The coronavirus cannot survive on items exceeding 60 degrees celsius. We used this knowledge to code and implement the Arduino system to allow the user to set a desired temperature and for the oven to heat up to that temperature with a face mask inside it to hopefully disinfect it. Using the PID, the oven heats up in small bursts over time, with feedback from the thermocouple, the oven reaches the desired temperature and then the user can leave the mask inside the oven for however long they like to disinfect it.
How I built it
The code was completed in C and C++ with the open source Arduino IDE. The physical electronic components used an Arduino Mega board, an encoder to set a target temperature, a thermocouple to keep track of the temperature, a relay to control the amount of power going into the oven to match the temperature, and an LCD screen to display the current temperature of the oven and it’s target temperature.
The code causes the relay to send power towards the oven to heat it up if the current temperature is too low for the target temperature. Otherwise it causes the oven to receive no power to heat itself up if the current temperature is too high. Hopefully with a little fluctuation, the oven will reach the exact temperature the user targeted and will be able to hold that temperature for however long the user needs it to.
Challenges I ran into
The biggest challenge I (Eduard) ran into was learning the actual Arduino IDE as well as it's physical hardware. It was quite a change for a software developer to deal with hardware but I faced this challenge head-on and conquered it. I used my previous knowledge in software design to implement C and C++ into the code. I also used a variety of libraries found in the github repo to help accomplish the tasks I needed to achieve. I learned a lot regarding the hardware aspects of Arduino with the help of Igor. He had a lot of experience in mechanical engineering and it really helped me overcome the challenge of implementing code physically into hardware.
Accomplishments that I'm proud of
This project was made to implement a prototype to solve a sample use case that anyone (whether they be in healthcare or not) will find useful. Disinfecting face masks to use during the pandemic will allow masks to be reused multiple times in a safe and healthy manner. This will allow the general population to go out during the pandemic safely to gather any essential items such as groceries. In addition, healthcare workers may find this useful with the current shortages of medical equipment in North America including face masks. This leads to how medical organizations such as hospitals and research labs can use a similar version of this device to reuse potentially infected face masks. This can also be used by the general population to reuse masks and to better protect themselves.
What I learned
More regarding C and C++ in the Arduino IDE. I also learned a lot regarding the physical Arduino board and additional hardware.
- Arduino main board and additional breadboard
- Buzzer addition
- Encoder addition (both rotatory and switch)
- Thermocouple (receiving and using data regarding temperature)
- Relay (low and high outputs to wiring and power to modify amount of electricity sent)
- LCD (Writing, clearing, updating information on screen; logic regarding modifying info painlessly on screen)
What's next for COVID Face Mask Sterilizer
The one main addition to this prototype that would've been added with extra time is an option for the device to use a buzzer to play a jingle when the mask has been heated for a certain amount of time. To elaborate, the user can set a target temperature as well as a timer using the encoder. The mask can be placed inside the oven where it now heats to the desired temperature and begins the timer when it can stay at the target. When the timer that the user set is up, the oven will automatically turn off and the buzzer will play a song every few minutes to alert the user the mask has finished disinfecting.
Please check out the Github Repo for the code!