
Bitcoin Vending Machine - kiba
http://blog.maschinenraum.tk/2012/07/15/bitcoin-vending-machine-exchange-euro-coins-for-bitcoin-wallets/
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reitzensteinm
Note the carton it comes out in; the bitcoin receipts are printed out ahead of
time, and stuffed into the vending machine like a pack of cigarettes.

A more advanced vending machine would purchase the bitcoins in real time, with
the correct exchange rate, and print out the receipt on the spot. That would
actually be pretty cool! Especially to think about security; you can rob a
standard vending machine, but you can't steal it, disassemble it, and trick it
into ordering thousands of bitcoins.

While just as functional (assuming a stable exchange rate), this particular
device has zero notability as far as cool hacks go. It's a bog standard
vending machine with bitcoin für euro painted on the side.

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vasco
Declaring it has zero notability as far as cool hacks go is highly subjective.
I for one think this is much cooler then the usual CRUD to-do list webapps we
see around here so much.

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alttab
I like the cut of your jib

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178
Hi, artist here. I want to use the moment of attention to ask around for ideas
on how to conceptually build the reverse of this. The current idea would be to
also use a web wallet, ie. you would preload an easywallet.org wallet with
some coins, then give the URL to the machine (type, QR, whatever) and it spits
out cash. There must be something more clever to solve the problem of
transaction verification (inside easywallet it's instant and we don't have to
wait 10m) and authentication (if the machine would receive your bitcoins on a
special address, how the machine know you sent it?).

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tomflack
There are NFC bitcoin wallet apps for android aren't there? And "POS" NFC
apps? Just cram an android board and an NFC reader in it set to accept taps,
look up the exchange rate and spit out cash.

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178
NFC has 0 users in my area, so later on this would be an option. But what
about something right now, not involving complicated tech?

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tomflack
Bitcoin probably has less users in your area than people with NFC capable
phones. I think for an art project this is a non-issue.

I also think if you consider my solution so "complicated tech" then this
probably isn't the project for you.

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mjschultz
If there was a moment to use QR codes for something useful it would be that
receipt. The last thing I want to do is type some 34 character case-sensitive
id into my browser to get my money.

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178
There is a QR code on the receipt, it is just hidden under the small box so
the internets does not steal my 1 €.

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vrotaru
Send the E to your main wallet and show to QR code.

It would be quite intresting to watch later the statistics of access

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kalleboo
Is there any way a practical Bitcoin ATM could be done? I.e. a machine where
you can get cash Euros/Dollars/Gold from your bitcoins. The naive approach is
it just has an address you send BTC to, but then you have to stand around for
30 minutes while the transaction is verified.

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highpixels
Something like that, but it could be done ahead of time - receive a bitcoin
address & redemption code online, send your coins then ~30mins later go to the
machine, enter your redemption code and receive your BTC.

Redemption code could also be a QR code. Put it on your phone & hold it up to
the machine.

~~~
HostFat
You can instant accept any bitcoin value that is lower to the investment to do
the 51% attack or similar. Example: no one is going to make a 51% attack to
steal only 10 bitcoin from a vending machine.

Simply put a limit, or just say to the user that any amount of bitcoin over X
will need Y time to get verified. Anything lower that X amount will be
instantly processed.

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fryguy
Doesn't it require ~10 minutes to solidify into the record to prevent double-
spending without having the 51% attack?

~~~
elliottcarlson
Correct - there are various attack vectors besides the 51% attack. Ideally, a
transaction shouldn't be closed until there have been 2 confirmations.

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mtgx
I still think NFC proliferation would be a great thing for Bitcoin.

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nathell
This reminds me of the fingerable Coke vending machine of 1982
(<http://www.cs.cmu.edu/~coke/history_long.txt>).

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erikb
You should definetely use QR Codes if you want to print it on paper. I think a
"secure enough" ID would be really a hassle to insert into your browser just
with your fingers. Or you sell small USB sticks with just enough flash to
store your link on it (in which case increasing the minimum to 10€ would make
sense).

Or maybe I'm just too simple minded and you have some creative ideas to make
your IDs secure and handwritable for my Grandma?

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zokier
I thought this would be a vending machine that would accept bitcoins. That
would have been more interesting

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the_mitsuhiko
Funny how the inverse would not work.

