Everyone who’s donated blood, gotten an intravenous (IV) line put in, or has taken a blood test knows that little bit of anxiety before the needle goes in. Will this be a one stick operation, or will the phlebotomist do their impression of drilling for oil while trying to find a vein? Some of us are blessed with easy to find blood vessels. Others end up walking out looking like they’ve been in a fight with a needle.
wife girlfriend is a nurse who’s had trouble finding veins in the past. [Alex] is an automotive engineer by trade, more acquainted with oil lines than veins and arteries. While he couldn’t help her himself, [Alex] designed this 3D printed vein finder to help his wife girlfriend out at work. He started by studying devices on the market. Products like Veinlite use LEDs to illuminate the skin. Essentially these products are a string of LEDs and a battery. They are patented, FDA approved, and will set you back between $188 and $549 USD. [Alex] and his wife girlfriend couldn’t afford that kind of cost, so he built his own.
The LEDs are the key to this device. The deoxygenated blood in the veins absorbs light, which makes the veins appear as dark lines on the skin. [Alex] found that it takes
15 11 LEDs between 620 nm and 680 nm. The LEDs also need to have the proper brightness. Less than 4000 mcd won’t be bright enough. More than 6000 mcd will blinding to the user. A few current limiting resistors, a switch, and the electronic design was done.
The case took several revisions to get right. Veinlite uses a C shape, which allows the IV needle to be passed through the slot and inserted in the lite field. [Alex] was able to clone this design in his own vein finder.
If LEDs aren’t high-tech enough for you, there are other devices out there which use a camera and projector to create an augmented image of the veins right on the patients skin. If you want to go more than skin deep, check out this DIY CT scanner from the 2015 Hackaday Prize.