Vein watcher

Posted: December 16, 2009 in Uncategorized

This project has a certain purpose, in hospitals the doctors or assistents has to inject people with needles, now they also have to inject baby’s. The problem is these so called neonates have very chubby hands so you easily miss a vein, while injecting the needle. To overcome this problem I build a very simple and cheap device to make the veins visible and make it easy to see where you have to inject the needle.

The solution is a very simple one actually, because you can not see the vein’s with the eye you need something to “see” through the little hand. To see through the hand I used an infrared power led which is so powerfull that it shines through a human hand. The next problem is, you can not see infrared light so you need a camera with infrared vision. An infrared camera is really expensive so I decided to make one myself.

Making the infrared camera wasn’t that hard because I already did it once. I took an ordinairy webcam of 5 euro, removed the infrared blocking filter by removing a little peace of glas that is green and red colored. Then I used an little peace of picture negative, the black colored piece at the end of a strip and replaced the IR blocking filter with that. By doing that you make the IR light pass the filter, but block the normally visable light.

To make the illuminating device I used an “OSRAM – SFH4230 – IR EMITTER, 2.4W, 850NM”. This is an IR led with 2.4 watts, so a lot of light and a lot of heat! To overcome the problem of the heat I used an heat sink. Because it has to look child friendly I put the led with heat sink in a toy frog, see the picture below. The power supply is a 9 V battery and the led is placed in serie with the led. In the “Utrecht Medical Centrum” they already build a device that does a bit the same, but it definetly is not as cheap as mine.

I’m dutch so I called it the “ader-kwaker” which means in english “vein croak”. Here below are some more pictures made with the IR camera. The pictures are quite good, and you really can see the veins of the hand. For this prototype it’s a really good start. The needle also is nice visable (the needle is not in the skin itself).

The toy frog at 2,4 volts:

  1. Pete J says:

    I just wanted to say what a great mind you have. I came to this site to see the CNC machine you built and found all the other projects listed that you have done.

    The vein watcher is a nice product and thinking of ways to do good things cheaper is excellent. Thank you for sharing and good luck with all the projects you do in the future.


  2. Tan says:

    Hi..a great job u ve done…i was wondering how u designed the power supply and the heat sink for the led’s and how the led’s are connected..whether in circular fashion or in some other manner…can u plz provide the link..


    • jjshortcut says:

      I did not make a schematic of it but it’s straight forward, just a resistor in series with the LED (just one 3watt LED). The resistor has to be a big one cause of the current flow through it. The LED was glued to a small heat sink of 10 by 10mm.

  3. Steve says:

    could you please send me any other info you have on this project, or sources for the light etc?

  4. jonny says:

    hi there! thats a pretty cool project!
    I was wondering if that device works in daylight or in a dark setting only.
    sorry if that should be obvious.

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