LED Water Purifier

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Introduction: LED Water Purifier

I was walking through my local camping supply store the other day when I came across this water purifier that cost $50 (I know outrageous) Being the DIYer I am I took a closer look at it to find that it was simply Some UV lights. Then it hit me, I can make this way cheaper. So I did.

HINT: start your soldering iron and hot glue gun now so they warm up

Step 1: What You Will Need

Here is a list of all the tools and parts you will need.

PARTS

- some ultraviolet LEDs, I used 4

-A small switch

-One resistor for each LED, Mine were 330 ohm

-Black tape/ Electrical tape

-Some wire

-Small plastic or glass container, This should be watertight and clear

-A battery, Mine was a 7.2 volt RC car battery

TOOLS

-Solder Iron

-Solder

-Wire cutters/ strippers

-Hot glue gun with hot glue

-Scissors

I had some stuff but I had to buy the LEDs ($2 Each) and the switch ($1 for a pack of 5)

Step 2: WARNING

This is from the label on the bag that the UV LEDs came in.

"This LED produces intense ultraviolet light. Exposure to UV radiation can be harmful. Protect your eyes and skin when operating. Never look directly at the LED. Buyer assumes all risks using this LED."

Just so you know and don't try and hold me responsible either.

Step 3: Soldering Part 1

Now that you have everything Get out the soldering Iron and solder each resistor to each anode of your LEDs (anodes are usually the longer terminals)

Then wrap them in electrical tape.

Step 4: Soldering Part 2

Now solder all your cathodes together (the shorter end)

And solder your anodes together on the other side of the resistor.

then solder a wire onto each and wrap in electrical tape.

Step 5: Solder on the Switch (part 3 of Soldering)

Now onto the anode wire solder a little switch on. and solder a little more wire onto the other end of the switch.

And just in case you haven't caught on wrap your connections in electrical tape

I used a momentary switch because UV lights are dangerous and I would not want it to accidentally turn on and stay on.

Step 6: Time for the Container!

Now take that small little clear container and put your LEDs in while leaving the switch on the outside.

To get good results bend the heads of your LEDs to make sure that they make an even spread of light.

because i do not have plans to fully submerge my container I just made the top of it water resistant by sealing it with tape and hot glue.

Step 7: Hook It Up to a Power Source

I tried using a smaller battery for this but none seemed to prove themselves worthy so I Ended up using a 7.2 volt Nickel Cadmium R/C car battery.

It was fairly easy to connect but I did not solder direct to the battery because I NEVER do that no matter how much wire is in between. its just dangerous.

Step 8: Operation

To use it simply expose by partially submerging the UV LEDs to your water for about 30 seconds and your water should be good and 99.99% bacteria free.

Thanks for reading.

EDIT: ok so it turns out that the LEDs I got are not quite powerful enough but this still gives you the basic concept. I would recomend that you get some 240nM UV LEDs they will raise the budget but it is worth it.

EDIT: (3/1/15) I made this several

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    user

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    81 Comments

    You can get, for example, Phillips UVC (germicide UV) bulbs and a quartz tube to put it in for about 25 euros, and do this sort of water purifying set-up, with some joints and ingenuity, much cheaper than buying one. I suppose it could go in a water purifier unit, Or something similar. It works quite fast, and would make a perfect end of the line in a purifying circuit. They use from 5 - 11 watts, which is reasonable.

    When I get round to it, I'll post my result on here... when I get round to water works!

    what frequency leds

    user

    Don't you mean wavelength?

    frequency and wavelength are both valid ways to describe light. they happen to be inverse quantities from eachother though. 280nm corisponds to 1070687.35 Ghz or roughly 1070 Thz. it is more commonly writen as 280nm though when discussing uvc

    user

    "Don't you mean wavelength-1?"

    "Greetings to you today, fine employee of Mantech electronics. I wish to procure exactly twenty of your finest Light emitting Diodes, preferably of the frequency 1070 Tera-hertz."

    Said nobody ever.


    Its true that we speak of light in terms of frequency, but when we start speaking of LEDs, the correct way to quantify them is in terms of wavelength, measured in nanometers. To say this is the more common way is an understatement - every single datasheet for LEDs uses nm as the standard unit.

    This is a clever project, but please know that the plastic housing you put the LEDs in is almost certainly not UVC transmissive. Just because it looks clear to your eyes does not mean it is UVC transmissive. You would have to shine through something like fused quartz glass in order for the concept to work!

    I'm kind of new to this, but wouldn't regular glass work?

    low iron glass or quarts (as mentioned ) is better for more than one reason. Many plastics block uv... worse yet, many plastics break down when exposed to it. Plastic + UV + water...might = drinking plastic. Normal glass has a slight green tint to it. its best seen looking at an edge. That green comes from iron mixed in with the sand its made from. It used to be an impurity but now its added in a controled percent to increase flexability (if memory serves)... it has the unfortunate effect of blocking/reflecting a lot of light below about 400nm. UVC is < about 300nm... again from memory but should be close.

    meant to add This info comes from my research before designing a vacuum press uv exposure box for uv lithography/etching circuit boards. I havent looked into uv-c transparancy in low iron glass but im guessing its beter than many/most plastics

    I'd recommend quartz glass, cyclic olefin polymer/copolymer, and/or specifically blended acrylics. Those are really the only handful of materials with even slight amounts of uvc transparency.