COVID KILLER 1.0 - 3D Printed Automatic Hand Sanitizer Add On
Description
Hi, my name is Arjun Melwani - I am an 8th grader (14 years old) at Greenhill School in Dallas Texas. After 30 days, 14 prototypes, 106 hours of Design, 5 all-nighters (in a row), 1.2 KG of ABS Filament, and my blood, sweat, and tears, I bring you the COVID Killer 1.0. A couple of weeks ago, before the panic began, I was standing in line to get into the grocery store. The store had manual hand sanitizer pumps lined up, but I noticed barely anyone was using them. I soon realized people were worried about the cross-contamination of interacting with the hand sanitizer pump, and if they could get the virus from using it. I thought, why not just replace them with automatic hand sanitizer pumps, when I learned that they can cost upwards of $50 USD. I knew I had to change this with 3d printing, and so the journey began. I designed a low-cost solution to converting manual hand sanitizer pumps into an automatic pump, for a fifth of the price of other solutions. I personally didn't have access to too many parts due to the outbreak, as well as my own personal budget, so I had to design it around widely used parts that I had laying around. This made it difficult at times, but in the end, it makes it more accessible for everyone. Even after the design was working, I continued to redesign it, over and over until I felt it was the best it could be. One of the best features of the design is its modularity - the design consists of 10 different parts that snap together with the snap-fit connectors I designed. The snap-fit connector (iterated over 60 times) allows for the parts to fit together like Legos, but then be strong enough to stably hold the design together against a lot of force. You can watch the build video: https://drive.google.com/drive/folders/1e0S4KWNq_ME_xKh8JliN_oOnuhQJPKFU?usp=sharing or at the post-printing section below where this is demonstrated. This allows for parts to be exchanged easily if they break, and for the model to work universally between manual sanitizers, servos (with the correct strength), and electronics. This is because the main body of the part is separated between two snapping parts that can be easily exchanged. Depending on the sanitizer bottle used, the bottom part can be easily exchanged due to this modularity. This also applies to the servo and electronics box. As it stands, there are only models of 3 different hand sanitizers, but as soon as more people use the design, more hand sanitizer bottles, and servo sets can be added. Currently, automatic hand sanitizer stations cost upwards of $50, but my unit costs less than $10 (including electronics and plastic) and takes less than half an hour to assemble. If the electronics are bought in bulk, this price can be reduced even further to less than $5. This would be highly beneficial for places such as grocery stores, and essential businesses to use, as it would stop the cross-contamination of the bottle that occurs from touching it, making more people inclined to use the sanitizer. Also, this design can easily limit how much sanitizer each person uses, as many times people will waste valuable hand sanitizer with the pump design. The design became super popular over Instagram - 40+ story shout outs, over 1400 views, and over 90 comments. The Instagram post can be found here: https://www.instagram.com/tv/B_HekgbAT1m/?utm_source=ig_web_copy_link The design-build is very simple and all that is required is very basic soldering skills and a small understanding of electronics, but this is walked through in the build video. The soldering and electronics is not walked through, but you can see the diagram of how to do this. For the Arduino code click here: https://drive.google.com/drive/folders/1e0S4KWNq_ME_xKh8JliN_oOnuhQJPKFU?usp=sharing Now for the technical specifications: Recommended Components: Common MG995 55-gram servo https://www.amazon.com/Analog-Digital-Helicopter-Airplane-Control/dp/B07RMD1BH4/ref=sr_1_3?dchild=1&keywords=mg995&qid=1587145814&sr=8-3 https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20200417095721&SearchText=mg995 FC-51 IR Proximity Sensor https://www.amazon.com/OSOYOO-Infrared-Obstacle-Avoidance-Arduino/dp/B01I57HIJ0/ref=sr_1_3?dchild=1&keywords=proximity+sensor&qid=1587146320&sr=8-3 https://www.aliexpress.com/item/32321964595.html?spm=a2g0o.productlist.0.0.29b0135bXAZ0yK&algo_pvid=d11c4f68-21cf-4969-b60c-5b1eccc1500e&algo_expid=d11c4f68-21cf-4969-b60c-5b1eccc1500e-1&btsid=0ab6f82315871464282948039e528f&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ 5v Regulator - A ton of options, from small microchips to BECs. I used a BEC, as they tend to not heat up much, but I am sure a cheap 7805 chip would work. Here are a couple of links: https://www.amazon.com/s?k=5v+regulator&crid=J06P3ULL30MX&sprefix=5v+regu%2Caps%2C200&ref=nb_sb_ss_i_1_7 The one I personally used (but I do not recommend as it is a bit pricey): https://www.amazon.com/gp/product/B07DYXTX9H/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Alixpress: https://www.aliexpress.com/item/32833224524.html?spm=a2g0o.productlist.0.0.11d11643iwtcrr&algo_pvid=5f47a2d1-3fb7-401f-996d-0b23e2ecbd05&algo_expid=5f47a2d1-3fb7-401f-996d-0b23e2ecbd05-1&btsid=0ab6f83915871470246541281e1bb9&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ The Micro controller: Almost any Arduino Compatible microcontroller will work, but here are the requirements: Fits in a 20 mm x 60 mm area, but smaller the better – I would try to go smaller – withing a 20 mm x 45 mm area. Compatible with Servo.h Arduino Library Has at least one digital PWM pin, and at least one digital pin. This allows for a ton of different microcontrollers at a range of prices. As long as it fits this criteria, it does not really matter which microcontroller is use. I personally used a Teensy 3.2, as it was the only microcontroller I had laying around, but it is very pricey for this application. I have found that the for the price, an STM32 Blue Pill board works well, but it could be a slight struggle to fit in the electronics box. It costs about $1-2, so is worth the hassle, and I have gone ahead and created an electronics box top to better fit the STM32. I recommend just researching what you can get the best deal on, but those are the only two I have had experience with. There are a ton others, such as the Arduino Nano Every that I have never used but are well rated and will work correctly. Here are links to the STM32 Blue Pill (Cheap Option), Teensy 3.2 (Expensive Option): STM32 Blue Pill: https://www.aliexpress.com/item/4000829230115.html?spm=a2g0o.productlist.0.0.3e0a3f79EqLaaA&algo_pvid=06d833fc-1cf9-484a-bbc8-912d151cc1ec&algo_expid=06d833fc-1cf9-484a-bbc8-912d151cc1ec-2&btsid=0ab6d69515871513979754230e42bc&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_ https://www.amazon.com/Aideepen-STM32F103C8T6-Minimum-Development-Learning/dp/B078KFK12V/ref=sr_1_7?dchild=1&keywords=stm32&qid=1587153337&sr=8-7 Teensy 3.2: https://www.sparkfun.com/products/13736 https://www.amazon.com/PJRC-6485230-Teensy-Original-Version/dp/B015M3K5NG/ref=sr_1_3?dchild=1&keywords=teensy+3.2&qid=1587153612&sr=8-3 Side Note: You will be able to fit the electronics with pins, it is just very hard, so I recommend not using the pinned version of boards. Other: You will need Dupont breadboard jumpers, thin hookup wire (can use breadboard jumpers,) a 9V battery, a 9V battery connector, a small male and female connector of some type – could even be a Dupont Connector. I used an xt-30 connector but anything you have should work. You will also need two M3 screws – a 10 mm screw and a 16 mm screw.
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