One of the hardest parts of taking blood can be finding a suitable vein. Some patients are 'difficult sticks'; their veins are either very small, and/or deep, preventing health professionals from finding a site easily and quickly. Repetitive needle sticks are painful for the patient and may also lower their confidence in the ability of the phlebotomist performing the stick.

Many companies now market 'Vein Finder' products, but these products can cost over $5,000 (depending on quality and utility). That price tag is often outside the means of smaller clinics or facilities. This is a guide intended for hobbyists and DIY problem solvers -- not staff of a large hospital looking for high-end tech to aid in routine venipuncture. 

This tool works by using near-infrared wavelength LEDs to illuminate the flesh at the site. The veins will appear as dark bands because they are more absorbent of this spectrum of light than the surrounding tissue. It is similar in principle to holding your hand over a flashlight (something we all did as kids).

Estimated Time to Complete: 3-6 hours (depending on your plastic cutting and soldering ability)
Estimated Cost: ~15-50$ depending on shipping/availability of free samples/if you need to buy solder, spare wiring, misc.

Below is a quick video of it working, moving it up and down my forearm. It's hard to document how clearly the veins appear because of my camera's minimum focal distance, but this ought to give you an idea (imagine no blur!):

Step 1: Required Materials and Tools

Soldering Iron
Rotary tool, with attachments suitable for cutting through plastic
Safety Goggles
Respirator/dust mask
Needle Nose Pliers x2 (I found these useful)

Blank Circuit board
Rocker Switch, On/Off (I used)
Resistors, 56 OHM, 250mW, 1% (I used) x30
LED 3mm, 20mA, 1.9V, λ 628nm (I used) x30
Plastic Enclosure with battery contacts and PCB screw holes (I used OKW enclosures' Part# A9072129, with Part#s A9190002 and A0304031)
Friendly Plastic, Black/Black (I bought mine here)
Wire (less than 1' needed)
AA batteries x2

Step 2: Cutting Your PCB and Enclosure

Measure your enclosure and cut your PCB to a size that will fit so that you know what kind of area you are working with. When cutting the PCB be sure to wear breathing protection as the fine dust from these boards may be harmful (with sufficient, prolonged exposure).

Cut an opening on the side of the enclosure, to fit the switch.

Cut an opening on the top of the enclosure, and then again on the bottom of the enclosure. The bottom hole should be wider, so as to allow the LEDs to peek out, while leaving the middle open.

Cut the PCB board into a 'U' shape (almost like a tuning fork), so that the opening will align with the other two openings you made on the top and bottom of the enclosure.

If necessary, cut away some of the PCB to make room for the switch on the side.

Step 3: The Wiring and Soldering

The specifics of wiring will vary from project to project, but I found that staggering the LEDS by one hole per row allows them to be packed more densely.  Your wiring should resemble what I've drawn above. We see the several sets of resistor-LED pairs in parallel with each other. You need not use all 30 that I advised you to purchase -- they are just so inexpensive that it makes sense to buy extra just in case.

I've also made the mistake of not including adequate room for PCB mounting screws in my illustration. It's very important that you DO account for these before beginning to solder.

This may sound dumb, but it's important to be careful which side you are attaching the components to -- that the side you've cut out for the switch actually line up. For example, in the drawing, although I've shown the components as if you could see them, they are in fact facing INTO the page, and their wiring facing you, out of the page. See the other photo of the real device to see what I mean.

Step 4: Assembly and Friendly Plastics

Once you've soldered all the parts to the cut board, screw the board into the enclosure, attach the wiring to the switch and solder, and attach the wiring to the battery contacts and solder them as well. Screw the enclosure closed, and pop in some batteries. Let there be light!

But it's not ready to use yet.

If you try it on yourself, you'll notice that the sides of the LEDs emit too much light to clearly see the veins -- regardless of how narrow the LEDs' viewing angle. This is where the miracle of Friendly Plastics come in.

You can read more about how to use them on other sites, or on the manufacture's page but the method that I used was to cut small strips and then heat them in near-boiling water. The strips, although 'hot', have very low thermal conductivity so they will not burn your fingers. This allows you to shape the plastics around the edges of the LEDs, so that they do not emit light into the viewing hole -- only down, into the skin.

Step 5: Test It Out


Now try it on the underside of your forearm; press it into your skin rather than merely hover over it. You should be able to clearly see veins as you pass by them, some you may not have known were there.

Unfortunately it is very hard for my camera to capture the exact effect (intense, bright lighting, coming from a small area to focus on), but I've attached a blurry image which hopefully shows some of the results -- I've drawn thin green lines through the veins I was able to see very clearly with the tool.
Very excited to have this project be featured as a finalist in the UP! contest. Thank you everyone for your continued support and feedback on this project -- It was fun to build, and I hope to keep writing instructables that give others even better ideas. <br> <br>Best, <br>Dan
And in buildings these. I dont have a rotary or that many specialty tools except for a nice solderi g iron. So i would like to start of with a base design that i could then just make my own instead of builing it from scratch. So has anybody found something that i could buy. Sorry for all the mistakes, wrote on small phone where i cant see the screen of what i am typing and the keyboard at the same time, also its like 4 hrs past my bedtime, ive been trolling the internet. I plan on buildi g one of these or something similar if u or anybody else has a newer/updated building specs or another cheaper, easier build will u please email me a copy to plh75231@gmail.com. I would gteatly appreciate it. Thank u very mucj.
I want to make one, has anybody found a flashlight or... that they can buy to use as the structure or base of the devive. Sorry not sure if i used the exact wording there but i think yall get what im trying to say. Anyways, a flashlight or... that u can buy and then just revisr or edit certain parts. Like just replace the LED's or diodes with the correct ones? Have u tried using 2 or 3 different wavelengths in there at the same time and maybe even having a switch to use all 3 wavelengths at the same time or just 1 at a time? Would this work if i took a led flashlight and replaced with neccesary gear, i guess im asking do i have to have the viewing slot? Or would i be able to see the viens from just the glow from around the outside of the flashlight? Also there is square flat led flashilights that they make, pretty much sae size and style of urs except without the viewing hole. Could that work? Can u have led's actually touching the skin or do u have to have plastic inbetween led and skin? Or do u just need a slight space between skin and led? I've been a Game Technician for over five years, working on games that u would see at Dave and Buster's or Six Flags or any major theme park. We haf a million dollars worth of games that i was in charge of. and have the knowledge to build one of these. Just not the expertise in led wavelengths
<p>i've uploaded my files together with a new instructables because the design requires some build instructions<br>Edit: forgot to put the link<br>https://www.instructables.com/id/3d-Printed-Medical-Vein-Finder/</p>
Very interesting idea, i could definitely use tgis device where i live. Because other methods are jjst unaffordable. I have one question though, the wavelength you used doesn't that fall under red light wavelength?
<p>Alex, how many have you made?</p>
<p>about 10 that use batteries AA , 8 that use rechargeable battery pack , that recharge to a nokia charger without the need to open the device , and 15 that look similar to flashlight for small children ( they have small arms and the leds are too far off </p>
<p>hello and very than you for all the device you made i would love to have the images that you have before please your device seems very easy i m nurse en mexico in pediatric oncology hospital they dont have a devide like this(politcs) and woul love you could help me please my mail is agf4023@gmail.com</p>
<p>Thanks first of all the wonderful idea. I was wondering if you could help me out I am made the vein finder so I can enter a high school science competition however I have a problem. It works and I bought the same exact material as you except mine cannot locate any veins. Like when I project it on an arm there are no black lines or anything!! Can you please suggest how I can fix it!!!</p>
Would you be able to email me please? godfrey.tuitama@gmail.com
Could you email me please, godfrey.tuitama@gmail.com
<p>I need some help i made it but it isn't working help!!!!! AlexS154</p>
<p>Dear Alex,</p><p>Thanks first of all the wonderful idea. I was wondering if you could help me out I am made the vein finder so I can enter a high school science competition however I have a problem. It works and I bought the same exact material as you except mine cannot locate any veins. Like when I project it on an arm there are no black lines or anything!! Can you please suggest how I can fix it!!!</p>
Well done! Thanks for sharing. Going to make one for my wife since she has difficulty with her veins rolling.
<p>hii.....i want to build a gadget which can find a missing object using infrared light...</p><p>please guide me on this</p>
hi guys <br>you can use super led - 1w.3w.5w - 620 nm(red) . 650 nm . 730 nm(deep red) - and use pcb for each led . <br>i use 3 super led - 1w - 620 nm - 350 ma - 2.2 v - and it just show my hand veins very well so i want use 650 nm and 730 nm -3w .5w <br>if you have some idea or you can help my or i can help you please Contact me . <br>mail : pbra1993@gmail.com <br>thanks
Hello , I really need help I want to make one so I will contact you and I wish you could help me .. thank you
<p>hi</p><p>who i can help ?</p>
Hi tried to contact you but there is a problem in the server so plz contact me : imenepapillion17@gmail.com
<p>Hi danbemp !</p><p>I tried making this but it does not work it seems. I used a normal Red LED for it and powered them on a 9V battery. I used ledcalc to use 82 Ohm resistance. RED LED's are 1.5v Forward Voltage and 20 mA. </p><p>Thanks. :) </p><p>Kind regards from India.</p>
<p>Great work danbemp!<br><br>Before deciding the the wavelength of the LEDs, did you consider the transmission, absorption and reflection properties of the different skin layers? Is 628nm based on a real study or estimation? I just want to be able to chose the right LEDs before I order them :)</p>
<p>clarify the weld layout of resistors and LEDs</p>
<p>I was trying to build this with a 920nm infrared from radioshack. I have learned that the LEDs I bought from radioshack probably have a wide beam and hence you need to enclose them in black goop on the sides. All I see is a blur on an IR camera. There are places online where you can purchase narrow beam LEDs of 10-20 degrees to focus the light. I intend to pursue that.</p>
<p>plz give me detailed explanation about it...plzzz which components can we use</p>
<p>waw itz amazing idea....i like it verry much....i want to add more specifications in it....</p><p>it is very nice..</p>
<p>Brilliant idea and exactly what I was looking for; I simply can't justify spending the amounts of money they're asking of a Veinlite. ...with that being said, I've spent a considerable amount of time and money on making incarnations of it below trying different things. My experiences are, use good quality LEDs, my first attempt has 22x10MCD 635nm LEDs and an open slot at the top. Passable, but only in a dark, dark room. My second and third attempts I'm not sure of the exact wavelengths but they're BRIGHT. My advice is to NOT open up the top to be crescent; exactly like you were saying, it lets too much natural light in and you lose the vein as soon as you turn it parallel to insert the cannula. I haven't figured out exactly how to get around this yet for my fourth (and final) attempt (final because I've just finished the third and I'm tired and frustrated that what was my best attempt, I ruined by opening it up to be a crescent) but I think it's just the way it has to be; leave it closed, find the vein and watch it like a hawk when you remove the light. Or you could mark it, and THEN swab it with alcohol??</p>
Can we buy one online?
<p>what can i use as an alternative for the friendly plastic ?</p>
<p>Can i use LED 630 nm?</p>
<p>Seems like this might be easier to build using common bus resistor network SIPs inplace of the individual resistors.</p>
<p>hi brother, I am surprised at the great project that helps patients Varjua that the information sent by the most beautiful on the project in order to apply it in the national</p>
<p>hi brother, I am surprised at the great project that helps patients Varjua that the information sent by the most beautiful on the project in order to apply it in the national</p><p>my email (oaoab2010@hotmail.com)</p>
This video is very cute to me. Always I want such project would be completed with great skill. I hope, only experts who are very experienced to this sector should research and apply in real works. To see more related topic: click here:&nbsp;<a href="http://www.whichisthebetter.com" rel="nofollow">http://www.whichisthebetter.com</a> Hope to well.
This video is very cute to me. Always I want such project would be completed with great skill. I hope, only experts who are very experienced to this sector should research and apply in real works. Hope to well.
Whoa man! Great idea! <br>Congratulations!!
A great project and good instructions. I have just one suggestion to simplify. Rather than use thirty 56 ohm resistors, just use one with wattage large enough to handle the total current of all 30 leds. Again, great job !
I'm an *extremely* novice 'electrical engineer', so you may be onto something here. However, I remember that when I was doing research for this project it was mentioned many times that it's better to use multiple resistors in parallel with the LEDs. Something about how diodes aren't very good at sharing current. When I saw that, I knew there could be a possibility of some of the LEDs getting very hot -- and when you're designing a device to be used on people, safety always trumps simplicity.
Hello - I'm an actual electrical engineer - and I can answer this. The reason you *must* distribute the resistors is because the LEDs all have slight different forward drops, and have very strong voltage/current relationships, thus if you put all the diodes in parallel, the one with the lowest turn-on voltage will turn on first (or turn on 'hardest') and hog all the current. It's actually called 'current hogging' in our business. Whenever you have devices with non-linear current vs. voltage and varying threshold voltages, you distribute resistors just like you have them. In this use, we sometimes call them &quot;ballasting resistors&quot;, since their job is to balance the current drawn by each nonlinear load (the LED in this case). I see the one-resistor suggestion come up all the time in forums - and actually several times in the comments to your project - but don't do it. It is a poor design practice. If you are lucky, one or a few LEDs will hog and overheat, if you are unlucky, the lowest turn-on device will smoke, followed by the next lowest, etc. until they are all toast. I hope this helps someone!
Fantastic!! May I make one suggestion to the build? Cutting the case at the top end so that you have an open slot, making it look more like a tuning fork. With that it would be more like the commercial units and it would be able to be used during the venous access and eliminate the &quot;eye off the ball&quot; that would take place when removing the light later.
I love this! When I have time, I might just have to do this. When I work NICU and pediatrics, we have a light that does the same thing but it shines&nbsp;<em>through</em>&nbsp;the hand/foot/arm so it's only useful on kids up to about 2 years old. I doubt it's very expensive because we have 2 or 3. This, though, would be great for adults who, surprisingly, are often much whinier about getting stuck. However, have you looked into the legality of using this in a professional setting? I wonder how much of the cost of the commercial devices has to do with needing FDA (or whoever) approval. Anyway, you're now one of my heroes!
Thank you so much! Please do build one, I'd love to see another one in action. <br> <br>Good call about the FDA -- I did some research and after a quick brush up on my legalese I think this device falls under this category: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=880.6350 , meeting the exception described here http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=880.9 . Plus, since it's not a commercially marketed device in this instance, it's build and use at your own 'risk'.
Long wavelength red LEDs (both 660 and 730 nm) can be obtained for reasonable prices here: <br> <br>http://ledgroupbuy.com/ <br> <br>The design of the device would have to be modified a bit to accommodate the different form-factor of the package, but at 1W each, you wouldn't need many of them.
There is a LOT of wasted energy with your multiple resistor design. I'd venture to say that you are probably burning more in the resistors than the LEDs themselves. It's just going to wear out the batteries faster. As long as the single resistor is sized properly, heat isn't an issue. You can find some forward voltage calculators online, especially helpful for the entry level. I like http://ledcalc.com/
Your link is telling me to put 24 resistors in parallel!
No. The resistors go in series. That way they get the same current through them. However there's a voltage drop off around 2v across each resistor so you could only do this with a higher voltage battery. If battery life isn't a big deal for you then I wouldn't worry about it.
LED's can have a little tollerence in the voltage required to burn. Lets say you have 2 LED's which you bought in a bundle, then the first LED can require 3.05V to burn, but the second one might need 3.10V to burn. Using only resistor will reduce the lifetime of the LED's becouse they are burning at a differend voltage then required. <br>Giving each LED it's own resistor will increase the lifetime of the LED's. <br> <br>Also, it is a bit of work to solder the resistors, but where I buy them, resistors cost 8 eurocents per 5, so it isn't worth to leave em out for the price. <br> <br>ps. Funny thing to try: use a 3V coincell (CR2032) and place a red and a green LED over it, what happens is that only one LED will burn becouse of the different voltages required. The same thing might happen with 30 paralel LED's, some might not even go on.
Oh, and about the lost power in the resistors: <br>Paralel resistors: <br> <br>P=U*I = I*R*I = 30(number of series)*0.020^2(current squared*56(resistence) = 0.672W <br>Power = voltage * current <br>Voltage = Current*resistence <br> <br>1 big resistor: <br>R=(30/56)^-1 (becouse 1/R = 1/R1 + 1/R2 + ... + 1/R30 = 30/R1 with R1=R2=...=R30) <br>R= 1.867ohm <br> <br>P = 1.867(ohm) * (30*0.020)^2 = 0.672W <br> <br>Both situations give the same power. With the extended lifetime of the LED's, I would recommend the 30 resistors as used in the Ible
Why does this remind me of a stud finder? It's very clever. Would you get better contrast with IR LEDs? If so, the device can be used in conjunction with a camera-equipped smartphone to see the IR light.
I read your comment this morning and I've been thinking about it while at work. On the one hand, I *do* think you'd get better contrast with IR light, however, using a camera to see the light has the drawback of not being able to easily mark the veins. You need to be able to do this to still know where the veins are when the device is taken away. <br> <br>It's still an interesting idea, and a very creative solution. As an aside, I was thinking this may be how the accuvein tool works, with one additional feature. Basically, the accuvein may use IR light to see the contrast between flesh and veins, and then the computer in the device maps that image and displays it back onto the same patch of skin it's viewing. Just a hunch. Thanks for the comment.
How to make an affordable 'Vein Finder', for use during venipuncture is a topic that needs thorough explanations as done in the University of Nigeria site <a href="http://www.unn.edu.ng" rel="nofollow">http://www.unn.edu.ng</a>

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Bio: Med student and DIY'er
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