Vein Finder

I designed and fabricated a handheld Vein Finder to help medical staff locate veins more easily across different skin tones. The system uses red and yellow high-power LEDs, chosen to maximize vein visibility under different lighting and skin conditions.

One of the main challenges was thermal and power management. The device runs on ten high-power LEDs, which required careful handling of heat and current. I connected the LEDs in series and used a boost converter to step up voltage and regulate current. This simplified the design, improved efficiency, and allowed the device to operate continuously for about four hours on a single charge.

Another challenge was integrating the PCB with the mechanical design. The LEDs mount directly on the PCB, making it both an electrical driver and a structural element. To achieve this, I created a custom PCB outline and fabricated it on my CNC milling machine.

For the power source, I chose a rechargeable 18650 Li-ion cell because of its robustness and safety in medical environments. To ensure safe operation, I added a simple LM358-based battery monitor that drives a warning LED when the charge drops to about 20 percent.

The enclosure was initially 3D-printed in PLA for prototyping and later switched to ABS for better durability. A future commercial version would be produced in injection-molded plastic for strength and scalability.