What it does

This device aims to allow for the addition of an array of UV-C LED's to existing cash registers, providing a shopkeeper the means to retrofit their existing cash registers with a light controlled device that sterilizes the money contained within. The UV-C LED's shall only be triggered to turn on when the cash register has been closed, at which point the money is bombarded with UV-C light, killing the microbial life within.

What is the problem you are going to solve? *

Sterilize currency so that it reduces it's possibility as a transmission/retransmission vector. Limit employee's exposure to UV-C as this process occurs. Automate the process of currency disinfection by building it into the existing infrastructure in as low cost a manner as possible.

How I built it

The device is governed by quite simply triggering the UVC LED's by making use of an LDR as the trigger mechanism. The design is akin to most 'IoT 101' articles, in the sense that the technology is the same as one would use to program 'Christmas lights.'

Retrofit existing cash register/Point of Sale systems

Trigger the UV-C lights turning on by waiting for the light dependent resistor to signify that the register is closed, and has been closed for more than several seconds, then for the Nano/555 timer to trigger a MOSFET/opto-isolated relay which then completes the circuit to deliver power to the UV-C LED's.

When the till is reopened, the lights should turn off again, so as to minimize an employee's exposure to the UV-C light.

Remaining challenges

Adequate dispersal of light in the closed till environment. Shipping & fulfillment of UVC LED's.  It'll require quality assurance through due diligence testing to determine that it's design assumptions are correct and that it performs as intended {safe for staff & effective at sterilizing the currency}.

What's next for Team UV-C LED Cash Register

See if the design is accepted and if we could roll out PCB designs for testing, then ideally mass adoption.

Try It out



arduino, c, ldr, led, nano, uvc

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