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The tiny chip that powers Montreal subway tickets

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Re: The tiny chip that powers Montreal subway tickets

#151

Post by lmz »

Tijdreiziger wrote: post #135
ak217 wrote: post #96

Earlier quoted context omitted.

Thanks for the write-up. How does this fit into the broader NFC ecosystem? What do other big metro systems like Omny, Clipper, Smartrip etc use? Apple and Google seem to implement some NFC protocols in their devices but in a much more programmable way, how does that work? Is the protocol used in credit cards related at all? And how do these relate to Felica, the system used everywhere in Japan (which was in the news…

> Is the protocol used in credit cards related at all? In e.g. London and the Netherlands, the readers were upgraded to support tapping in and out with a debit/credit card or Apple/Google Pay. However, Apple also seems to have an ‘Express’ mode, which even works when the battery is empty (‘Power Reserve’). It seems to me that there must be three protocols: the one for the disposable and stored-value tickets (ISO 1444…

EMV (specifically EMV contactless) is also based on ISO 14443, it's more like an application layer protocol on top of it.

Apple Pay Express is just Apple Pay without the need for the full system UI: "If iOS isn’t in use because iPhone needs to be charged, there may still be enough power in the battery to support Express Card transactions." it interacts the same way as the physical card equivalent (otherwise they would need a reader upgrade).

Re: The tiny chip that powers Montreal subway tickets

#152

Post by speed_spread »

Sytten wrote: post #108

They are going away soon (TM), the tech is cool but they are impractical. I will be happy to use my credit card or phone. Too many times I have been stuck in 15-20 minutes queues to buy those tickets and you cant refill them with an app... Plus south shore and north shore have they own system it's a mess.

You can refill them with the Chrono app since last March. No more queues. Can't do nothing about Laval and Longueuil though.

Re: The tiny chip that powers Montreal subway tickets

#153

Post by MBCook »

kens wrote: post #145
MBCook wrote: post #131

The article says the chips are made on a 180 nm process and they come out about the size of a table salt grain. We’re now down in the single digits for fabrication in nanometers, although I know that sort of just a name. This chip is so tiny already, if you were to fab it on a process like 7 nm I’m guessing it would be unworkably small. Too hard to cut, too hard to manipulate individual chips once you did manage to c…

There are a few issues. First, you lose 20 µm due to the saw cut between the dies. I saw an NXP patent that said this was wasting 30% of the die for their tiny chips. If you made the chips smaller, you'd be wasting even more. Another issue is that you need some area for the bond pads, so you can't make your chips arbitrarily small or they will be useless. Looking at a random die pick-and-place machine [1], it handles…

0.2mm per side? Wow that’s smaller than I’d expect. Thanks.

The increased losses due to cutting make sense too. I was expecting the cuts to be wider than 20 µm, so that’s not actually as bad as I was imagining.

Re: The tiny chip that powers Montreal subway tickets

#154

Post by paulmd »

bobthepanda wrote: post #132
akpa1 wrote: post #124

Earlier quoted context omitted.

I'm looking forwards to the day they somehow manage to link a National Railcard to a contactless bank card.

I feel like the approach will probably be that railcards become digital wallet compatible.

costco already has this for ID cards in the states (and I've also seen it for account ID for home depot and some other places where it's tied to discounts). the app will pull up an ID card with a QR code that changes every 60 seconds or so to prevent screenshotting and trivial reuse, which is analogous to the function the chip performs in terms of challenge-authentication.

Re: The tiny chip that powers Montreal subway tickets

#155

Post by mardifoufs »

chgs wrote: post #123

Mifare is what’s been used in London’s Oyster cards for 20 years (not the ultralight ones mind), and Hong Kong for even longer. However oyster really is in its way out for most uses. contactless and especially a phone is far more convenient for non season use, and far less wasteful.

I think there are plans for contactless smartphone tickets in Montreal too. I wonder why they haven't done that yet, it's been years since they've started talking about it.

Re: The tiny chip that powers Montreal subway tickets

#156

Post by lbourdages »

ForHackernews wrote: post #122

> a per-chip price of nine cents That still seems expensive for a $3.75 metro fare. 2.4% of the cost of your ride is the chip in the ticket itself? Maybe it's worth it because it lets them eliminate mechanical ticket-reading and unify paper tickets with other NFC payment methods.

These single use tickets are used essentially only by tourists and those who use public transport only on occasion.

The vast majority of users will use rechargeable Opus cards [1] that can contain a variety of different fare types (single tickets, monthly tickets, etc).

From an operator's point of view it definitely makes sense to only have to maintain one type of reader, even if that means losing a few cents profit on the low single digit percent of rides that use the disposable tickets.

[1] https://www.stm.info/en/info/fares/opus-cards-and-other-fare...

Re: The tiny chip that powers Montreal subway tickets

#157

Post by markus_zhang »

II2II wrote: post #143
markus_zhang wrote: post #98

Earlier quoted context omitted.

I have found the same thing with my wife. I'm a technical person, but I'm extremely bad with tools and such, including the ticket thing. If no one shows me how to use it I'll probably figure out a way to insert it somewhere. My wife won't have any problem with this and other small tools. The same thing with IKEA: I always rely on the manual and just blindly follow the instructions, and gets very frustrated if the ins…

> The same thing with IKEA: I always rely on the manual and just blindly follow the instructions, and gets very frustrated if the instructions miss one step. Following instructions is a good thing. Plenty of people damage stuff when putting it together since it looks obvious, but they usually miss critical details. I would imagine that the people who designed the card scanners had to put a lot of thought into their d…

Yeah...but apparently she is more handy than me. I always joked she should work as an engineer of some sort.

Re: The tiny chip that powers Montreal subway tickets

#158

Post by mardifoufs »

speed_spread wrote: post #152
Sytten wrote: post #108

They are going away soon (TM), the tech is cool but they are impractical. I will be happy to use my credit card or phone. Too many times I have been stuck in 15-20 minutes queues to buy those tickets and you cant refill them with an app... Plus south shore and north shore have they own system it's a mess.

You can refill them with the Chrono app since last March. No more queues. Can't do nothing about Laval and Longueuil though.

Yeah they added refills but you can't use your phone as an NFC pass yet :(. I've always been curious to know more about why, you'd think if you can refill your Opus card with your phone, to then use it on the terminal, you could just skip the card step entirely but I'm sure it's not that simple!

Re: The tiny chip that powers Montreal subway tickets

#159

Post by mardifoufs »

kens wrote: post #93
dgudkov wrote: post #75

Earlier quoted context omitted.

>Montreal subway does not cover the entire region like Vancouver's skytrain. It's not supposed to. The new REM train network (a few stations already in use) will cover the region. By 2027. Maybe. REM will also go to YUL. PS. Fun fact, REM is also driver-less just like the Skytrain.

Strangely enough, I used the ticket in the article for the REM train (from Du Quartier, where I was staying).

Yeah the Montreal area transport system uses the opus system (the disposable cards are part of that) for everything. Sadly, it's now bizarrely more complicated with the weird zones that they recently added after half a decade of consultations that were meant to... stream line intercity travel! for example, if you take the metro in Montreal, then ride it until Laval, you have to buy a specific type of ticket with the two zones.

Meaning that if you just buy the normal ticket in any Montreal station and make the mistake of going to Laval, you can be fined and they do tons of ticket traps because they know that people make that mistake pretty ogten. It's not even a separate line or something. And the same card wouldn't let you take a bus in Laval because again, it's another ticket (but not the same as the one for the dual zone metro that I was talking about earlier...). Just a huge mess when it used to be much simpler before they "streamlined" it.

Re: The tiny chip that powers Montreal subway tickets

#160

Post by MBCook »

lmz wrote: post #151
Tijdreiziger wrote: post #135

Earlier quoted context omitted.

> Is the protocol used in credit cards related at all? In e.g. London and the Netherlands, the readers were upgraded to support tapping in and out with a debit/credit card or Apple/Google Pay. However, Apple also seems to have an ‘Express’ mode, which even works when the battery is empty (‘Power Reserve’). It seems to me that there must be three protocols: the one for the disposable and stored-value tickets (ISO 1444…

EMV (specifically EMV contactless) is also based on ISO 14443, it's more like an application layer protocol on top of it. Apple Pay Express is just Apple Pay without the need for the full system UI: "If iOS isn’t in use because iPhone needs to be charged, there may still be enough power in the battery to support Express Card transactions." it interacts the same way as the physical card equivalent (otherwise they woul…

Right. Much like the fact Find My functionality can still let you track your phone when it’s “dead”, the power requirements are just so low that when the phone can’t get going due to the requirements of the CPU + RAM + display there’s plenty to power NFC/BT beacon stuff for a while.

An AirTag can operate on a CR2032 for two years. An Energizer datasheet says that’s 235 mAh. An iPhone 13 Mini has a 2438 mAh battery (~10x). It makes sense the phone could do it for at least a day or two with the left over charge.

(I don’t know how long it would actually keep working)

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