DIY Ultraviolet Sterilization Device (UVClean)

Introduction

Hi all and welcome to my very first instructable! In this step by step guide, you will learn how to create your very own ultraviolet sterilization device that can be used as either a wand, or as an automatic sterilization chamber. The device, called the UVClean, uses a special UVC bulb that can sterilize nonporous surfaces in a matter of minutes.

Features include:

-Sturdy and ergonomic design

-Genuine 253.7nm 3.5W UVC bulb

-Bi-color OLED display

-Passcode protected interface

-Comprehensive menu system

-Continuous handheld mode, and automatic timer mode

IMPORTANT EDITS: I did not know this would blow up so much, but thank you to everyone who has taken a look! I have a few important updates to say based on some thing I have been seeing in the comments.

1) Build this device at your own risk, a lot of people have a lot of things to say about UV safety, and I am certainly not an expert. I will try to answer some questions about it, but at the end of the day you should do some good research on the safety precautions that is required for UV exposure before you decide to build this device.

2) This device is in fact a sanitizer, not a sterilizer. Sanitizing is the process of removing most organisms from a surface 99.9%, while sterilizing is the process of removing ALL organisms from a surface. This device is not medical grade, and it should not be perceived as such.

3) This device has not yet been proven to kill viruses and bacteria. I will be testing it soon, see point 4.

4) I will be testing the effectiveness of the device soon. To do this I will be growing some bacteria cultures and exposing them to my device for varying amounts of time. I will then observe the growth of the bacteria to see how effective this device is at eliminating them. I will be sure to post pictures and videos of this experiment on my instagram and on this instructable in the coming weeks, so stay tuned!

WARNING: This device emits UVC radiation, which is harmful to human skin and eyes. Proper UV protective goggles and full body skin coverings must be used when testing the bulb circuit, and when operating the device in handheld mode. This device must not be operated in the presence of any animals or unprotected humans. As a safety measure, a passcode must be entered to arm the device, so as to prevent unauthorized users from turning the bulb on.

All CAD, code, and circuit diagrams were originally created by me in light of the COVID-19 pandemic. If any of you have any suggestions to make it better, or if you want to make any modifications of your own, please do so and let me know all about it! If you do decide to make one, please send me a picture of it!

About me:

My name is Henry Mayne, and I am currently a 3rd year electrical engineering student at Northeastern University in Boston. My roommate and I enjoy making projects like this one, and want to pass our ideas on, so please check out our Instagram to see some of our other projects and things that we have been up to. If you want to know about my career history, check out my LinkedIn page.

Supplies

Tools required:

-3D printer

-Laser cutter or saw

-Multimeter

-Soldering Iron

-Solder wick or solder sucker

-Hot glue gun

-Lighter or hot air gun

-UV laser goggles

-Heavy duty gloves

-Helping hands

-Allen wrench

-Screwdriver

-Scissors

-Exact-o knife

-Pliers

-Wire strippers

General Materials:

-PLA filament (any color)

-Aluminum tape

-Electrical tape

-Rosin core solder

-Hot glue

-Super glue

-8x 20mm M3 bolts

-18x 10mm M3 bolts

-26x M3 nuts

-Stranded copper wire

-Heat shrink tubing

-2mm thick clear acrylic

Electronic Components (Must be these exact pieces to work, I will provide links):

-GTL-3 UVC bulb

https://www.amazon.com/gp/product/B07835252H/ref=p...

-E17 mountable bulb socket (it is very important that you get this EXACT socket, so it fits in the print)

https://www.amazon.com/gp/product/B07J4ZTYWZ/ref=p...

-Power supply (it is very important that you get this EXACT power supply, otherwise you will run into issues)

https://www.amazon.com/gp/product/B083DSPRQG/ref=p...

-Boost converter board (it is very important that you get this EXACT board, otherwise you will run into issues)

https://www.amazon.com/gp/product/B07RT8YXSH/ref=p...

-MOSFET High power switch board

https://www.amazon.com/gp/product/B07XJSRY6B/ref=p...

-3x 150 ohm 5W resistors

I got these at my local electronics store, but maybe you can find some online

-Arduino nano

https://www.amazon.com/gp/product/B07KCH534K/ref=p...

-Rotary encoder module

https://www.amazon.com/gp/product/B07YFPV5N4/ref=p...

-Toggle switch

https://www.amazon.com/gp/product/B079JBF815/ref=p...

-OLED screen

https://www.amazon.com/gp/product/B072Q2X2LL/ref=p...

-2.1mm barrel jack

https://www.amazon.com/gp/product/B074LK7G86/ref=p...

-Small piezo buzzer

https://www.amazon.com/Gikfun-Terminals-Passive-El...

Step 1: 3D Print the Pieces

The first step is quite simple, use the provided .stl files and a 3D printer with a suitable bed size to print all 10 of the custom pieces (You will need 2 window panels and 2 shroud plates). Make sure to level your print bed and wipe it down with isopropyl alcohol before each print, especially for the large shroud panels. I suggest printing one piece at a time, because if your printer is anything like mine, it can be prone to failure. Set some time on the weekend to print out all the pieces because it will take many hours to complete. Lastly, make sure to constantly monitor your 3D printer, since it is a fire hazard if left unattended.

Step 2: Laminate the Shroud With Aluminum Tape

Using a roll of aluminum tape, scissors, and an exact-o knife, laminate the inside of the front plate, back plate, left and right spine, both shroud plates, and both window panels. This will help channel the light from the bulb towards the sterilization area, as well as act as a massive heat sink for the bulb and resistors. In order to make this easier, try to cover large areas with whole pieces of tape first to avoid too much cutting. Once the pieces are covered, use an exact-o knife to trim the edges and the holes.

Step 3: Cut and Install the Acrylic Windows

Using a saw, or laser cutter if you have one, cut some appropriately sized acrylic panes that will fit into the rectangular depressions on the window panels. Next, place the pieces into the depressions, and run some super glue along the edges. If done properly, the super glue will seep into the cracks all by itself and the window will be firmly secured. Make sure to use only a small amount of glue, and do not touch the acrylic so as to avoid getting glue-fingerprints on it. Once you have applied the super glue, let the pieces dry on a level surface for 24 hours. The UVC radiation will not pass through the acrylic panels, but the visible blue light from the bulb will pass through, giving the device a cool looking effect.

Step 4: Assemble the Shroud

Using 3x 20mm M3 bolts, 16x 10mm M3 bolts, and 19x M3 nuts, assemble the newly laminated and windowed shroud. Begin by attaching the left and right spine pieces together with one 20mm bolt in the middle hole. Next, slide the front and back plates into place and secure them each with the remaining two 20mm bolts. The back plate can be identified by the 3 holes on it, and it should be mounted on the side where the grip will go. Now, attach the two large shroud plates and window panels using the 16 10mm M3 bolts. Tighten all the bolts to keep everything secure.

Step 5: Install the UVC Bulb and High Power Resistors

Solder the 3x 150 ohm 5W resistors in parallel in order to get an equivalent resistance of 50 ohms. The reason for using three resistors instead of 1 is to decrease the power dissipated through each individual resistor, and increase thermal mass. The resistors have to dissipate quite a lot of power for the bulb to work properly, if only one resistor were to be used, it would get extremely hot and become a fire hazard. Next, solder the 50 ohm equivalent resistance in series with the E17 bulb socket, with proper wire lengths as seen in the picture above. Secure the E17 bulb socket to the inside of the shroud using the remaining two 10mm M3 bolts, and use a piece of aluminum tape to secure the resistors directly below the socket. Then, run the two wire ends through the hole in the center of the back plate. In the end, the inside of the shroud should look like the picture above. If there is any confusion in the wiring of the bulb and resistors, consult the provided circuit diagram.

Step 6: Program the Arduino

Upload the provided code to your Arduino nano, feel free to modify my code all you want, or even write your own from the ground up. I am excited to see what other people come up with. In order to upload, you must first install both the Adafruit_SSD1306 and Adafruit_GFX libraries to you Arduino IDE.The default passcode for the device is 3399, if you wish to change the passcode you must do it at this step. Find the section in the code seen in the picture above and replace the four numbers of the passcode to your liking. Once you are satisfied, press the upload button in the Arduino IDE and wait until it says done uploading.

Step 7: Test the Electronics on a Breadboard

Using the provided wiring diagram and the previously programmed Arduino, make all of the correct connections on a large breadboard. Remember to wear UVC goggles and full body skin protection when turning the bulb on, UVC is harmful to human skin and eyes and it is extremely important to limit direct exposure to the bulb. If everything works as expected, you can move on to the next step. Wiring can be tricky sometimes and it is important that you take your time with this step so that you get the connections right and understand how they work. (Disclaimer: Some of the parts in this picture are early prototype parts, but the concept is the same)

Step 8: Wire and Install the Electronics in the Grip

This will be the most challenging step in the entire project. If you do not have a lot of experience soldering and wiring projects with a lot of connections, I suggest that you practice a little bit before this. Make sure you know how to strip wires, make strong solder connections, use heat shrink tubing, and especially make sure you can keep everything organized. I made this pretty hard for myself because I only had one color of wire, but I really suggest you go out and buy a bunch of different colors. Before you even turn the soldering iron on, there are some important things to do. The first thing to do is to use a pair of pliers to bend the pins on the back of the OLED screen so that they are parallel to the back of the screen, and pointing towards the bottom. The second thing to do is to use some pliers to snip off the excess edges of the rotary encoder board to that it fits in the grip. Now that these important steps are complete, turn the soldering iron on and get some solder wick or a solder sucker. Using these tools, remove all of the pins from both the rotary encoder board and the Arduino nano. Next, use stranded wire and heat shrink tubing to attach long wires to the buzzer, screen, and encoder. After this is done, use a hot glue gun to secure the screen and buzzer in place, and screw the encoder in place. Now, using a pair of helping hands, trim the wires to length and solder them to the nano one by one, making sure to double check your connection points and insulate everything well with heat shrink tubing and electrical tape. It is extremely important that all of your wiring is as short as possible, otherwise there will not be enough room in the grip for everything to fit. Next, wire in the barrel jack and power switch, securing the jack with a generous amount of hot glue. For the final part, you need to begin by tuning the boost converter. To do this, hook the VIN terminals of the boost converter up to a 5V power source and use a multimeter to read the voltage at the VOUT terminals. Turn the small blue potentiometer with a screwdriver until the voltage at VOUT reads 25V. Next, wire in the tuned boost converter, MOSFET switch, and bulb assembly into the rest of the circuit, making use of the screw terminals on the MOSFET board. As a final measure, completely cover the boost converter and MOSFET board in electrical tape to prevent shorts.

Step 9: Complete the Final Assembly

Before you seal everything up for good, do a test of the electronics, making sure there are no shorts before you plug it in. If everything works as expected, tuck the Arduino, boost converter, and MOSFET board into the base of the grip near the power jack. Try to tuck any excess wire into open spaces in the grip before attempting to put it all together. To assemble it, begin by putting one half of the grip onto the mounting point on the shroud, and put two 20mm M3 bolts through the mounting holes to secure it in place. Next, bring the other half of the grip into place and push it into the two bolts. Then, put the remaining three 20mm M3 bolts through both halves of the grip. Using a small screwdriver, push any excess wires inside the grip until it can completely close. Finally, thread the nuts onto the bolts and tighten until the assembly is complete!

Step 10: Enjoy Using Your New Creation!

Make sure to follow proper UV safety guidelines when using this device, and never leave it unattended while it is on, as the bulb resistors can get quite hot. With that being said, enjoy using it and I hope to get a lot of useful feedback on my design!