I hope that you live near Miami to send it to the conference...

So great idea man!!! I love it.

It depends on amount you send. Transaction comes from few addresses. Denominations like 0.1, 1.0, 10 are in different addresses.


Oh, and I forgot


This is so cool  
Awesome

This is amazing Solarminer! Please excuse my curiosity, but what kind of hardware are you using to handle the Dash part? Raspberry?

Solarminer, thanks for the explanation. I also think the vending machine idea is a great example of the power and versatility of instantly confirming crypto. It's a fantastic initiative. But I can see some banana skins that you might want to think about before rolling it out to a public demo.

First of all, this:


...I don't think that's acceptable because it isn't commercially consistent and basically amounts to theft. Think two 13 year old teenage kids with iPhones who buy a coke. One gets change and one doesn't cos they're not technologically nerdy enough to check their denominations ? They don't really want to be faced with questions like "Darksend" "Not Darksend". It might as well be two different currencies.

Further, if change is involved, it should be on condition of supply of a change address, not the on condition of coin denominations. That way the service can be commercially consistent and also optimally serve instances of homogeneous denominations as your current design does. (Because it supplies an implicit change address, but heterogeneous payments then need the option of supplying an explicit one).


I'd just ditch the whole idea of change since it isn't really compatible with cryptocurrency (other than change addresses in wallets where the wallet itself has full control over everything). Just accept exact amounts otherwise no coke - since it's far easier for a customer to type the right amount into their wallet than be worrying about how their payment was denominated. Doesn't the QR code do that for them anyway ?

Sorry to be so nerdy about this but it's a great idea and I don't want you to get shot down by a*ssholes (other than me   ) who home in on the glaring banana skins of the concept only to ignore the huge potential of it.

Also, what you're demonstrating isn't really a vending machine, it's a metaphor for an entire commercial business model so it's the commercial priorities that need to be thought through, not the blockchain technicalities. In that regard, details like that change thing can explode in your face when presented to the "wrong" audience.

Exactly!

Look like you are trying to install Electrum Dash Client on x86 (32 bit) live linux system.
I think there are 2 options for you,
1. compile from source as instructed on your post.
2. try install on [x86_64/amd64/64 bit] live linux system if hardware support.

Hope this help.

Yes, toknormal, from the machines perspective both DS and non-DS IX are the same.
Darksent transactions have inputs we can send refunds/change to.

The machine will return non-ix transactions back to the first input of the tx, same with IX (DS or no) underpays.
Overpays get their change back.
But, considering the qr code has the price embedded, this was more experimental than practical.
The necessity of change from a vending machine is an artifact of fiat denominations that don't really apply anymore (tee hee).

Indeed. Thats why I think you should probably forget about it since it detracts from some if the great strengths of your demo, namely that:

[1] - expensive physical sensors for coinage are a thing of the past
[2] - coin-denominated money is a thing of the past
[3] - cash transactions can now be trust free and loss free

Of course, you've also got to look out for the "other side of the coin", i.e.

There nothing to stop a rogue vending machine from charging you $10,000 for a coke and the user not noticing. Maybe thats the bigger challenge than sending change. 

The amount to pay appears on your phone and then you have a pin to type in.
But I know what you mean.