1. Results/Expected Results
Laser Detection Method for Covert QR Codes Printed in Near Infrared Upconverting Inks
Jake Deutz (SDSM&T)
Faculty Advisors: Dr. Crawford, Dr. Kellar, Dr. Cross, Dr. Boysen
Abstract:
The International Chamber of Commerce projected that the global value of counterfeit goods climbed to a staggering $1.8 trillion in 2015, a three-fold increase from Thus, it is important to develop new ways to counteract the threat. We have shown that upconverting nanoparticle inks are a good method to mark products for authentication purposes. A laser is used to cause the inks to upconvert near infrared light to either visible or a different wavelength of near infrared. The purpose of this study is to further develop an the existing system (laser/optics/camera) that reads quick response (QR) codes printed with upconverting nanoparticle inks. The goal of this research is to make a more stable system and to redesign the laser system housing to make the system more portable.
Introduction:
Goal: Develop Complete System for Printing, Reading and Decoding Security Marks
Printing
-          Fluid Properties
-          Ink Jet Printers
Reading
-          Laser
o   Power Circuit
o   Wavelength
-          Camera
-          Optics
Decoding
-          Smartphone
-          Display
This work focuses on fixing the existing system particularly the circuit controlling the laser and making it more efficient.
Model the circuit and isolate components to figure out which part is not working.
Fix any problems found
Pick between two cameras
Circuit Problems:
The laser circuit to begin with was not working. To fix it we went through two methods.
Model the circuit
The circuit was accurate but we were unable to use the circuit analysis tools from the modeling program to get accurate results. However it was useful to have a way to show the connections of the circuit in a way someone new could figure out how to connect it.
2. Isolate the circuit components
To figure out the problem we took the components and hooked them up piece by piece. We were lucky and stumbled onto the problem early on. It was the voltage regulator that was cutting of power to the laser diode.
We replaced the oki-78s (above left) with the LM78XX (above right). It was easily available and it provided better connections then the old regulator.
Replacing that part got the laser to work again but the ink for the QR code was not upconverting and showing up on the camera. Through experimentation we discovered that the ink would not upconvert unless the current was at least 0.6 A. To fix this we found that the connection through the bread board were not constant.
To fix this we designed a circuit board (below)
We have not gotten it printed off yet but once we do it will fix our current problems with not getting a consistent upconversion.
Results/Expected Results
Once the circuit was working the problem was whether our new camera was giving a clearer picture (above right) or if our new camera (above left) was better. Tests are still being performed but currently the old camera looks like its giving a better image.
Acknowledgements
I wanted to thank all of my advisers at the school of mines for all their help with the project. I would also like to thank Scott Rausch head of the Electrical Engineering department at the School of Mines.
“This work was supported by the National Science Foundation (PFI:AIR  award # ).  Jake Deutz was supported by an REU supplement to the same award.”