Given the current state of events, we were inspired to create a device that was able to mitigate the transfer of bacteria through commonly touched surfaces, as well as provide a more efficient method of keeping track of the number of people entering or exiting a room for health and safety purposes. Due to the fact that this process is carried out manually, it is not possible to ensure that door handles are sterilized as often as they should be, as well, it is very difficult to keep track of the total occupancy of a room, especially if there are multiple entrances. Therefore, by creating this device we ensure that each and every doorknob is sanitized on a needed basis. It is our hope that the implementation of DHD will drastically reduce the transmission of the virus and other diseases.

What it does

Our product DHD functions by detecting whether a person is approaching a door through the use of an ultrasonic sensor. Once the person opens the door, the Hall effect sensor detects a change in the magnetic field as the process of opening the door separates the magnet from the sensor which triggers the disinfection process. This is indicated by a blue LED turning on. The spraying process then begins as a DC motor rotates and pulls the trigger on the spray bottle for a duration of five seconds. Next, a fan turns on in order to dry the doorknob, so that the door handle is prepared for the next user. this concludes the disinfecting process. The LCD display now registers that one person has entered the room and the "People Counter" increases by 1. After spraying about 500 times, a red LED then turns on to indicate that the spray bottle needs to be refilled. Once the device has been supplied with a new sanitization spray bottle the user must press a push-button to reactivate the device. To account for an individual leaving a room, after detecting a door closing, an ultrasonic sensor will check for an increase in distance as the person walks away. This is registered as an exit and the counter of the number of people in the room will decrease by 1. Essentially, the prototype is responsible for disinfecting a door handle after each subsequent use.

The desktop application functions via a Bluetooth module on the Arduino which is able to transfer the data it collects. Each disinfecting device installed transmits data about its current status, whether the device is on and ready, disinfecting, or off. It is also able to transmit the current number of people within a room, in addition to the maximum allowable occupancy (based on the current health restrictions), and detects cases where the room or facility is overcrowded. Finally, the application keeps track of the status of the devices installed in all rooms and tabulates them.

Who is it intended for?

This device was mainly built for installation in Office Buildings and for other businesses. As discussed previously, it helps create a safer work environment for employees and helps monitor the occupancy in the entire building autonomously. The enterprise would give an employee or security personnel the job of monitoring the occupancy limit in the various rooms every hour and that of refilling the spray bottles once a day, or as needed.

How we built it

DHD was built through a collaborative process that involved one member constructing the entire prototype while the other two members worked simultaneously to develop code for the device, as well as creating a desktop application that would collect emitted data from the Bluetooth module and organize it in a user-friendly manner. The prototype was constructed through the use of an Arduino, which was able to control all of the electronic components.

Challenges we ran into

Due to the fact that we had limited access to resources, it was a challenge to be able to create an entire working prototype with the hardware we had. Specifically, one significant challenge we ran into was the fact that the member responsible for the prototype did not have access to a Bluetooth module, so testing the desktop application in conjunction with the prototype was not possible. Although both projects function as they should carry out the tasks they were designed for as we simulated the connection between the prototype and the Desktop App using a separate Arduino and Bluetooth module, we would need to meet in person in order to ensure that they function together.

Accomplishments that we are proud of

Given the online nature of the Hackathon, we are very proud to say that we were able to create an entire functional prototype, as well as a desktop application, within a limited time frame. With few resources and capabilities to collaborate together, putting everything together was an accomplishment on its own.

What we learned

With all of us coming from the discipline of Mechatronics, it was a challenge to push ourselves outside of the scope of what we are taught in class. Since most of what we learn is theoretical, being able to practically apply our skills it was an interesting experience. we were able to explore a variety of sensors and other electronic components, as well as work with Java in an online fashion, where we were able to create a desktop application.

What's next for DHD Solutions

Moving forward we hope to equip DHD with a UV light in order to ensure the effective sanitization of each door handle. In addition, we hope to organize the electronic components more efficiently so that the device can be as compact as possible, which will include our own PCB design to minimize any extra unnecessary components. Finally, we hope to install a protocol that will adapt the spraying nozzle to accommodate any door handle and to be able to sanitize each one thoroughly.

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