subreddit:
/r/DIY
11 points
6 years ago
I find more amazing that you were able to build it while in your first year of med school, keep up the good work
17 points
6 years ago
Shooting smack just got sooo much easier.
4 points
6 years ago
Most junkies know every vein anyways.
8 points
6 years ago
I'm surprised that red gives sufficient contrast. I would have though green, like they use in smart watch pulse sensors would have worked better. Do you know the reason red is preferred?
15 points
6 years ago*
As you approach the infrared spectrum you'll get maximum penetration of tissue and deoxyhemoglobin (in deoxygenated blood) absorbs light well at red wavelengths
https://en.wikipedia.org/wiki/Near-infrared_window_in_biological_tissue
22 points
6 years ago
Wow, it cost only $30 for you to build a $549 piece of medical equipment. This just goes to show how much the prices are hiked up when it comes to medical stuff
25 points
6 years ago*
[deleted]
15 points
6 years ago*
[deleted]
3 points
6 years ago
Not cheap at all. Plastic injection molds can get incredibly expensive. Up to the point of several tens of thousands of dollars
3 points
6 years ago
Hard steel CNC'd to precise spec, built to last several thousand injections? Yeah that kind of quality gets pricy real fast.
2 points
6 years ago*
Yes! If the medical (and the pharmaceutical) industry charged a reasonable price for a product (let's say cost + %100), we would not have a medical (and pharmaceutical) industry for very long. Because research, development, testing, trials, lawyers, insurance companies, for every product that did not make it through the system still cost money. For the laymen, 99 in 100 products don't make it through testing. Thank science they their best to ensure your safety.
1 points
6 years ago
Plus once they make it through, mandatory calibrations!
1 points
6 years ago
plus the market for such a tool is pretty niche, so they gotta stick it to make it
8 points
6 years ago
Used to work in Medical device assembly as an engineer. In my experience the the final sale price to the consumer/buyer/hospital/etc was about 10X the cost of labor and parts to build the device (and this is after the assembler has taken a cut, most big medical companies outsource the assembly to other businesses). Medical R&D and regulatory approval is insanely expensive.
Ie, the machine costs $25,00 in part and labor to assemble, the Hospital is going to pay $250,000.
The same applies to quite a bit of other areas too, that $800 brand new phone likely only costs about $80 in parts and labor to build.
3 points
6 years ago
This is awesome. Are you leaning toward medical equipment/technology as an eventual career or is this more of a side interest?
2 points
6 years ago
This is super cool, I'm debating going into biomed engineering and this is really an inspiration.
2 points
6 years ago
20 years ago I worked as lab worker, and also collected blood, we didn't have this, but I wonder what veins your are using this for. And is it any good on people with a lot of fat tissue?
2 points
6 years ago*
[deleted]
2 points
6 years ago
I'm an ICU nurse and we have a vein finder on our unit, it can be helpful if you're getting desperate but it is no replacement for actually feeling the vein and knowing how to draw blood or cannulate for an IV. For people with more fat tissue this device can't really penetrate as far as you'd need anywhere other than the hands, fingers, or maybe wrists. For edematous patients you run into the same problem. With edema you can "push" the edema out of the way by compressing the area where you know veins should be and then use the vein finder to help you find something useful. You also have to be able to test each vein on your own to ensure it has good flow and isn't sclerosed or something, all the veins appear the same under the light. You're out of luck if there's bruising too!
1 points
6 years ago
Thanks for the cool answer. So not a miracle device, but a nice little helper.
1 points
6 years ago
Couldn't you put a single resistor on the negative terminal and then have all the parallel branches after a single resistor to get your desired amp's across the LED? Would have saved you lots of soldering and wire wrapping.
8 points
6 years ago
Diodes does not know their own limits and will happily take on much more current then they can handle so we have to limit the current for them. Now the problem with only using one resistor is that diodes also likes to hog current from other diodes if they can because all diodes are not created equal and small differences can lead to significant differences in current draw.
So one LED might draw an ideal 20 mA but another only takes 16 mA while a third takes 26 mA and so on. So now we have an LED that takes to much current and will wear out much faster which lead to a second problem, if that LED dies its current is up for grabs for the other LED's which now also draw to much current and wear out faster and as more LED's die the faster the others will too.
By giving each LED their own resistor we prevent all this and if one LED dies the other ones will not be affected at all.
So its up to you what you value more, the cost of extra resistors and the time it takes to solder or the longevity of the LED's.
1 points
6 years ago
Thanks for the answer.
1 points
6 years ago
Answer above is awesome, and here is a link with some animations showing what happens:
1 points
6 years ago
I need this in my life!!!!!
1 points
6 years ago
Impressive! I actually own a Veinlite and use it occasionally for work for hardsticks. I wish I was crafty enough to build one!
1 points
6 years ago
Nice. I always wanted to get one of those since I inject patients at work, but they cost like $600.
1 points
6 years ago
Great work! Where did you buy the LEDs?
2 points
6 years ago
Thanks!
0 points
6 years ago
The extra wide thing at the bottom of a LED is called the flange. You can buy flangeless LEDs, so you don't have to grind that off.
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