By Benedict Smith

Alex Stanciu, a military automotive engineer, has designed a 3D printable vein finder. Stanciu believes that the $25 DIY device, which is around 5 times cheaper than the leading market alternative, could be used by nurses and medical staff in developing countries.

The taking of blood samples is an important part of everyday hospital life. As unpleasant as a needle in the arm can be, blood samples enable doctors to accurately diagnose patients about a number of conditions. Collecting blood samples is a task frequently assigned to nurses, who are expertly trained to locate veins, usually in the arm area. But even for professional nurses, it can occasionally be hard to locate a vein, since some patients have less obvious or protrusive veins than others. Nobody wants repeated jabs in the arm as the nurse looks for a vein, so medical vein finders are a good way to prevent unnecessary distress and raise patient confidence in the medical team.

Unfortunately, professional vein finders aren’t cheap. A few hundred dollars might not be much to a large hospital in America, but it certainly can be to small medical teams in other parts of the world. Stanciu’s girlfriend, a nurse, lacked experience in finding veins, so Stanciu himself did some research on vein finders. Since purchasing one would have cost the majority of his partner’s monthly paycheck, Stanciu decided to make one himself using a 3D printer and some easily affordable electronic components.

After a number of prototypes, Stanciu eventually developed a near-perfect model, which is suitable for printing on cheap 3D printers without heated print beds. In order to eliminate warping, Stanciu used blue tape and alcohol, believing that this trick could be easily replicated in poorer areas using low-cost 3D printers. The 3D printed vein finder, which consists of three printable parts, took the designer around 4-5 hours to print, using a Sunhokey 2015 Prusa i3 RepRap 3D printer. Stanciu used a 0.25mm layer height for speed, but recommends 0.1mm for a near-perfect appearance.

Besides the 3D printed parts, makers will need a handful of other bits and bobs, such as resistors, batteries, and contacts. Most important of all, however, are the 15 LEDs, which need to have a wavelength of between 620 and 680 nanometers and a brightness of between 4000 and 6000 millicandela. This kind of lighting is enough to penetrate skin, fat tissue, and oxygenated blood, but not to penetrate deoxygenated blood—the stuff that runs through veins. When shining the light on a vein, the vein therefore appears much darker than surrounding areas, allowing the nurse to apply a needle to the right area.

Stanciu hopes that his 3D printed device, which is free to download and share for non-commercial purposes, could be used in the battle against the Zika virus. The vein finder has already received a number of positive comments from the Instructables and Imgur communities.