Fall 2020 Design I Final Competition
Section K: Team Bryce
Problem Statement: How might we mitigate the spread of COVID-19 through manufacturing a product that reduces the amount of touch-contact that customers of retail stores experience to limit transmission?
Team Members: Alex Chavez-Maldonado, Erick Johnson, Mila Kania and Willaim McGinley
Instructor: Karen Wylie
Hello Team Bryce,
Great Prototype and Video.
One limitation is that the disinfection can only work for line-of-sight surfaces. Grocery items stacked in the bag will shadow other items. How did this limitation affect your design?
What is the effect of short term exposure to UVC on fresh meats and produce?
Are there any material degradation concerns from using UV light bot on your solution as well as packaging?
How does the process of check out affect the sterilization of the items. (i.e. Remove item to scan and put back)
Thanks,
Garrett Erickson
Thank you for the great questions! Regarding the process of checkout, this was absolutely something that the team acknowledged while designing the product. At first glance, it almost seems pointless to put one’s items in the basket while shopping as they do in fact have to either scan their items out themselves or get them scanned by a cashier. However, since the UVC light has a kill rate of 99.9% after 25 minutes, much of the potential virus on items would be terminated before they get to checkout especially if they had a longer trip. After the the customer is finished checking out, they can leave the basket on during the ride home to ensure that their items are nearly completely free of the virus. By making the product more customer-oriented, they have the freedom to leave the basket on as long as they please, and it will be made known to the customer how long the lights should be on to kill different percentages of the virus most effectively.
Hi! Thank you so much for your questions! It looks like Alex touched on some of them but I can talk a little more about the lights and the process. He is correct that it takes 25 minutes for 99.9% of the virus to be killed but research also shows that it takes 8 minutes for 90% of the virus to be killed and 11 minutes for 95% of the virus to be killed which are both very high percentage and he is also correct in mentioning that making the product more consumer based they have the ability to control how it is used. So although the cashier may touch the products at checkout you would have the ability to leave them in the basket for 8-25 minutes after that and you would still be in control knowing who and how many people have been in contact with your products.
As for the effect of UVC lights a study published by the US National Library of Medicine showed that since UVC lights so not have the ability to penetrate objects there was no physical or chemical change to the meats or produce as a result of exposure to UVC light for an extended period of time.
In regards to your question about the line of sight of the lights, this was something we as a group of discussed in great detail throughout the semester. While nothing can every be perfect we have tried our best to incorporate everything possible to each as much surface area as possible. We made sure to incorporate lights with a surface area of 130 degrees on the top, edges and base of the basket as well as to line them inside of clear vinyl tubing to diffuse the light to a greater surface area. As well as since this is only a prototype we have also discussed the addition of lining the interior of the basket with a reflective material to help the light bounce around within the basket. With all of these precautions the light is able to hit as much surface area as possible and since it is a consumer product they would be able to move the items arounds within the basket to ensure more surface area is reached. According to a study the average American shopper shops for 43 minutes giving ample time to disinfect all surfaces.
Garrett,
In response to your question about material degradation; when selecting materials we decided to use PVC for the frame as well as a PVC canvas material for the exterior. We made this decision to use PVC based on research into the properties of PVC and its rated as having good UV resistance. The manufacturer of the PVC canvas lists the material as being UV resistant for up to 500 hours. In terms of degradation of merchandise place inside the basket, based on the relatively low time required for sanitization, material degradation is not too much of a concern.
Hi Team Bryce,
nice presentation and idea! I have a few questions
1. What about hiding surfaces of one item by another item – this will leave potential viruses protected from the UV-light.
2. What light intensity is needed for effective sterilization?
3. You mentioned that the light only turns on when the lid is closed but at several instances in your video the light was on while opening and closing the basket.
4. Is the audience only the general public? It seems to me that store owners and employees are also relevant stakeholders since they need to deal with the shoppers using the basket, and likely would be the ones providing them as a courtesy to shoppers.
Hi! Thank you so much for your questions!
In regards to your question about the line of sight of the lights, this was something we as a group of discussed in great detail throughout the semester. While nothing can every be perfect we have tried our best to incorporate everything possible to each as much surface area as possible. We made sure to incorporate lights with a surface area of 130 degrees on the top, edges and base of the basket as well as to line them inside of clear vinyl tubing to diffuse the light to a greater surface area. As well as since this is only a prototype we have also discussed the addition of lining the interior of the basket with a reflective material to help the light bounce around within the basket. With all of these precautions the light is able to hit as much surface area as possible and since it is a consumer product they would be able to move the items arounds within the basket to ensure more surface area is reached. According to a study the average American shopper shops for 43 minutes giving ample time to disinfect all surfaces.
As for the proper intensity of the lights, without access to the real UVC LED Lights we were unable to preform a luminosity test on the lights but we could determine based on research that since a property of UVC light is that it is a high intensity light and that any wavelength of UV light from 100-280 has germicidal properties that if we were able to run the LED lights with the correct voltage and wattage, which we were, that they would produce the right intensity of UVC light to deactivate the virus within the basket. Our lights also have a wavelength of 270 and since intensity is measured by watts times wavelength with a greater wavelength we will have a higher intensity of light.
Judith, thanks for your questions.
In regards to #3; the basket shown in the video footage is our works-like prototype. Due to budget constraints for the construction of this prototype, we used just purple LED light rather than actual UVC lights and did not implement an actual magnetic switch. This is why the footage shows the lights to be on when the basket is open; on the actual implementation of the final product this would not be the case.
In regards to #4; store owners and employees are very relevant to our problem definition. Based on engagement with these stakeholders, we determined that the price of our solution would turn off many retailers from investing in supplying the whole store with these baskets. Therefore we decided it would be most feasible to sell our product to consumers who could bring the basket to and from the store with them. An advantage of this is that products can continue to be sanitized after the customer has left the store.
Hello! Thank you for your questions! In regard to the activation of the light only when the lid is closed, this will in fact work for the final design in all practicality. This will be achieved through wiring a magnetic sensor to the circuitry of the UVC lights and battery; in doing so, the circuit will remain open (or off) when the sensor does not observe the presence of a magnetic field in close proximity. When the magnet that is attached to the lid gets close enough to the sensor, the circuit becomes closed, allowing the UVC lights to power on and sanitize the items inside of the basket. The only reason the lights (which were strip lights purely for demonstration purposes only) were on in the video is because the team was unable to wire the desired magnetic sensor to the battery due to certain restraints, but it would indeed be fully functionable in the final design. The team also decided upon a magnetic sensor through the use of a decision matrix compared to a light sensor and weight sensor for a multitude of reasons. This was very important for safety concerns as well, as the team wanted to prevent any possible injury or damage that might result from the UVC lights; although unlikely, this added measure was very necessary to the design of the product.
Team Bryce, great work.
It looks like Judith and Garret asked some great questions, so I won’t duplicate.
1. You mentioned the battery can run for 5.5 hours, is this a rechargeable lithium ion?
2. Is there some sort of battery warning system when it is low? I’d hate to get all the way to the store thinking I was going to disinfect everything and the batteries are insufficient.
Hi! Thank you so much for your questions!
In regards to your question about the line of sight of the lights, this was something we as a group of discussed in great detail throughout the semester. While nothing can every be perfect we have tried our best to incorporate everything possible to each as much surface area as possible. We made sure to incorporate lights with a surface area of 130 degrees on the top, edges and base of the basket as well as to line them inside of clear vinyl tubing to diffuse the light to a greater surface area. As well as since this is only a prototype we have also discussed the addition of lining the interior of the basket with a reflective material to help the light bounce around within the basket. With all of these precautions the light is able to hit as much surface area as possible and since it is a consumer product they would be able to move the items arounds within the basket to ensure more surface area is reached. According to a study the average American shopper shops for 43 minutes giving ample time to disinfect all surfaces.
As for the proper intensity of the lights, without access to the real UVC LED Lights we were unable to preform a luminosity test on the lights but we could determine based on research that since a property of UVC light is that it is a high intensity light and that any wavelength of UV light from 100-280 has germicidal properties that if we were able to run the LED lights with the correct voltage and wattage, which we were, that they would produce the right intensity of UVC light to deactivate the virus within the basket. Our lights also have a wavelength of 270 and since intensity is measured by watts times wavelength with a greater wavelength we will have a higher intensity of light.
Sorry I believe this reply was with Judith ^^ I will make sure to repost it under her questions
Hello Ryan,
In regards to your first question, this is in fact 3 rechargeable 3.7v lithium-ion batteries wired in series to achieve our desired voltage of 12 volts to run the lights. The batteries we chose have both over-charging and over-use protection, in addition to output short protection. The good thing about using a modular series design as we did is how we could increase or decrease the voltage and the capacity of the energy system simply by adding more or fewer batteries. Given stakeholder feedback, we decided upon the 3S design because of the cost-benefit, space savings, and an adequate amount of battery capacity.
For your second question, the charger we decided to use is a compact lithium-ion balance charger which will display the charge of the batteries while they are being charged. In addition, when the batteries are finished charging, we added 3 indicator lights to display the charge of the batteries on the physical basket which can let the user know what capacity the batteries have left at any time.
Hello Team,
Great presentation and video.
Few questions:
1. How is your product compare with the existing market solutions?
2. The cost is around $300 – are there any other costs related to maintenance? How often you need to replace the LED UVC lights?
3. Are the lights on all the time ? Or do they turn on when the person opens the container?
Thank you, Dr. H
Hi Dr. H! Thank you so much for your questions. I can definitely address number 3. No, the lights are not on all of the time. Since UVC light is only safe to humans in the form of far-UVC light or 222 nm and at other wave lengths can cause burns to the skin or eyes we had to find a way to address this risk. In order to mitigate this risk we incorporated a magnetic switch within the circuit of the design. This means that there is a magnet attached to the lid and one to the top of the rim of the basket. When the basket is open and the magnetics are not in proximity of one another the circuit is still open and no electricity is flowing to the lights in order to avoid direct contact between the consumer and the UVC lights. However when the basket lid is closed and the magnets are in proximity of one another then the switch/circuit is closed allowing for the UVC lights to turn on.
Hi! Thank you for your clarifying questions! In regard to a few of the products currently out on the market that you might have observed from the video, they are actually substantially different from our design for a multitude of reasons. To begin with, those products come in at a very high selling price and the cost-effectiveness of them are very minimal; for example, the leading brand (UV Clean House) markets their bag for $189.00 before any additional taxes. Now although this might seem fair for such technology, it doesn’t nearly compare to the amount of benefits that come from our design. Their product dimensions come in at 5.7 inches tall and 10.4 inches wide, whereas ours stands at 14.5 inches tall, 14 inches wide, and 15.5 inches long with over double the capacity of the competitor. Their bag is also made out of material very similar to a reusable lunch pack and clearly does not have the durability that our rigid and sturdy basket withholds. It is unclear what the weight of their bag might be able to hold, but one thing is for sure; it is no where near the upwards of 50 pounds that our basket can carry for extended periods of time. Their product does in fact shut off when opened as does ours, but in order to use the sanitizing potential the bag must be plugged in; ours can be used on-the-go for upwards of five hours, and this is only when the lights are activated, thanks to the rechargeable batteries. These are only a few things that make our product so unique compared to pre-existing solutions.
As briefly mentioned above and in regard to your third question, the lights will only be on when the lid is closed and the device is on. In terms of the circuitry, the team implemented an on/off switch that activates/deactivates the entire device. The user must ensure they turn this on before doing anything else. Once that is done, the rest is fairly automatic; a magnetic switch was implemented into the design of the basket (located on the top edge) that communicates with a magnet attached to the lid. In doing so, the user will not only be protected from potential injury or dangers caused from the UVC lights, but the lifetime of the battery will be maximized as power is not constantly being consumed. Although power is still used when the device is powered on and the lid is open (lights are off), this consumption is very minimal and will allow the product to be used for very long periods of time without the user having to worry about recharging it.
I can also answer your question in regard to the lifespan of the lights! The UVC LED Light chips that we chose have a lifespan of 10,000 hours. This would mean that if the lights were to run continuously they would last for 416 days. Although since the basket will not be used continuously we did some research on how often and for how long Americans shop. We were able to determine from a report done by the United States Department of Agriculture that the average American shops for 43 minutes, 1.6 times a week. According to these statistics the lights within the shopping basket would be able to last approximately 166 years. Therefore you would most likely never need to replace the lights only other components.