[Enthalpy]

Hi everyone !

In shops, one remaining Covid contamination path is money. An answer is to allege that money doesn't host the virus, I read that. Or we can try to tackle the problem.

UV light is known to destroy virusses, including Sars-Cov2. UV LED are available for near-ultraviolet Hg wavelengths, compact, reliable, efficient. This could irradiate the money between the cashier's and the customer's hands, in both directions.

The rest is mechanical design, still imprecise. The apparatus must stop the UV from exiting but irradiate both sides of banknotes and coins.

Both users could introduce the money at the top, say between a pair motorised soft rolls, and grasp it at the bottom, after an other pair of rolls. UV between the pairs of rolls would be blocked by the rolls. Nice for banknotes, but the coins would fall at once. It also needs a soft material that survives UV. This shape has the smallest footprint.

Or a platter would tun slowly. The customer has a sector to introduce and extract money, the cashier has an other sector, and the two sectors in between irradiate the money under a cover. Silica and variants make the platter transparent to UV.

Maybe banknotes and coins should have different paths. Possibly the soft rolls for banknotes and the platter for coins.

The apparatus must be easy to open, and opening must halt the UV emission. Fluorescent surroundings would reveal any UV leak.

Marc Schaefer, aka Enthalpy

[Borek]

Switching to contactless CC payments sounds easier and doesn't require extra hardware that will be thrown away after the situation gets back under control.

Can't remember when it was when I last used cash.

[Enthalpy]

Arguments against contactless:
- Germans don't want.
- I don't want. It tells where I am, what I do. It may help forge my bank card.
- I would cost me fees for each single payment.

[wildfyr]

Disinfecting cash is so much harder than using contactless payments, or even just disinfecting ordinary credit cards. A simple wipe with alcohol disinfects a card. Been doing it for weeks. CC swipe machines are very high contact points. You gonna make a billion of these money disinfection machines and distribute world wide? Or use the hundreds of millions of contactless credit card readers already out there and paid for. In German big cities I didn't have too much trouble using a card. Only in small places. In many countries card use is near universal.

I got $120 cash out of the bank 7 weeks ago. Have not spent a cent. Everything done on card, or contactless payment on my phone or an app. I bet I spend under $300 in physical cash per year these days.


#1 and 2 "I/Germans don't want" is a terrible reason, or rather not one at all. For location, Do you carry a smartphone? Most people do. Your location is known if a government party cares to know. For forging bank card, most banks and ALL credit cards will cover transactions made with stolen card info. Its the law in the US I think. Other countries should adopt this, its part and parcel of broad card use. Europe is the place that started using chipped cards and increased card security anyways.

#3 at least in America credit card fees are assumed by the store. Of course this is ultimately passed to consumer by price increases.

What sounds more important to you:

"I/Germans don't want because stubborn, and location privacy (when 99% of people have smartphones in pocket anyways)" or "public health during pandemic." Its the old "security vs freedom" debate.

Lastly, UV is not the way to disinfect paper cash or any porous material. Too many micro/nanocrevices won't be irradiated. Aerosolized antimicrobials would be the way to go.

[Enthalpy]

Whatever your opinion or mine about using contactless payment, the Germans won't. Same in many other countries. And I carry no smartphone, in fact no cellular phone at all, location being only one of the issues.

I'm confident that UV reaches the depth of a banknote. You can see through a banknote.

[wildfyr]

Don't you think where its dyed it will be UV impermeable? The extinction coefficient of visible dyes in the UV is usually quite high. I think you see through many tiny "holes" between the fibers of a banknote, but it is not transparent. Some countries use plastic notes, other use plant fiber still. Also visible light has deeper penetration depth than UV since the wavelength is 2-4x longer, so that is not fully indicative. UV also will cause damage to bill polymers over time.

You are unusual in not carrying a cell phone, and that is just the way the world is. Most Germans carry cell phones. Heck, most human beings do now. Expanding use of highly reliable existing technology is much simpler than creating a new one and convincing everyone to install it. Period.

In major German cities the credit card infrastructure seemed as good as anywhere on Earth to me. Paid at bars, restaurants, and shops. Would you agree that not having a cell phone and credit card causes you significant amounts of extra hassle in exchange for your perceived security?

[Enthalpy]

I'd be happy to perceive security.

Germans don't pay by NFC, and this hasn't changed with Covid. I see everyone pay with coins, banknotes or credit cards.

A solution for some countries doesn't apply to others. Sure enough. In some gold miner villages of French Guyana, gold is the money, and everyone has scales. No-one has a phone nor Internet, so credit cards fail.

You don't need all shops to install money disinfectors. Commerces that are concerned enough from meeting hundreds of people daily may adopt a disinfector, others not.

Banknotes opaque: we need UV to reach the same places as virus do, which is essentially the surface. If a banknote is folded at one place, neither the virus carrier nor the target will touch that place.

[wildfyr]

FYI many credit cards now have contactless payment in the card itself. I just got one in the mail.

[Enthalpy]

So do I. I wrapped my card in aluminium foil.