Comments on: Less is More—Interface Simplification for Vending Machines

By: David Rivers

David Rivers — Sun, 22 Mar 2009 01:54:49 +0000

I much like this. With a motion sensor, you can even deactivate all lights until a potential customer is within range.

I also think that this system could reinforce the visual indicators with a very simple audio feedback mechanism, which would make it more usable (a “success” bell for a proper selection and a “fail” buzz for some kind of erroneous input, such as the selection of a sold-out item or underpayment for the current product choice), and this would be pretty cheap to implement.

By: Clay Barnes

Clay Barnes — Thu, 20 Nov 2008 10:52:47 +0000

@David Hamilton:
I understand the association, but I am not always offered my receipt after making small credit transactions—often the same ones where I am not asked to sign. I would say that credit cards warrant receipts less than cash for small transactions like this. The latter case lacks documentation, whereas the former can be seen either in the monthly bill or the online card purchase history. If the cash vending machine transaction model precludes receipts, I don’t see a compelling need for them when using credit/debit cards.

Perhaps I’m jumping the gun on paperless transactions, but I think it’s immanent for small purchases with credit/debit cards.

By: David Hamilton

David Hamilton — Thu, 20 Nov 2008 10:38:20 +0000

My reply to your comment about the receipt printer is simple: “You’ve never seen a credit card reader on a vending machine either, have you?” I certainly haven’t, but it’s not a bad idea, and in my (possibly grossly atypical) mind, credit cards and receipts just sort of go together.

By: Clay Barnes

Clay Barnes — Thu, 20 Nov 2008 10:04:11 +0000

@David Hamilton:
Since there is an ambient light-level sensor built in, the issue of impeding visibility is simple to overcome. At a given light level, the on-board computer can select differences in selected/unselected item illumination that are easily recognizable, but which do not impair visibility of unselected items. The data for this is probably available from industrial design research, but if not, it would be fairly easy to test in the R&D phase of production.

I didn’t think about a receipt printer when designing the machine because I don’t think I’ve ever seen one on a vending machine. I suppose one could be installed, but it would add complexity for a use-case that I suspect is rare.

For the alternative product storage layout there are still simple solutions, they simply call for each item to be staged in the display as it reaches the top of the sales queue. This is pretty trivial for soda, which might be displayed just above the center bar and carried by a conveyor belt a just below its opening so it needn’t drop more than a few inches when vended (The belt would deposit it in an opening on the right of the center bar.). As for the freezer, the glass display could be mounted on the top and the whole setup, including an open-topped freezer, angled somewhat towards the consumer. The vacuum-grabber could still be used (I’m sure that the novelty of that mechanical system is one of its products’ selling points); similar to the soda machine just mentioned, it can deposit the product in a side opening. If the system is too energy-inefficient even with several layers of glass, the opaque, insulated freezer cover could be kept—just mount pictures of the various products over their respective stacks. When the user touches the glass to select something, open the lid to show the products. This makes the process following the initial selection identical, including error detection/correction.

By: David Hamilton

David Hamilton — Thu, 20 Nov 2008 09:23:06 +0000

More thoughts occur to me. Some of them trivial, such as possibly a receipt printer? Some people use receipts to track their expenditures, most especially when those expenditures are made using plastic.

Others are less so: This design seems to assume analogue with the sorts of machines that dispense candy and snacks and such. What might you do with other sorts of machines, with different internal layouts? For example, many beverage vending machines store drinks not in many horizontal racks but in a small number of vertical ones. Or to cite a more extreme case, the machines which vend frozen confections, and involve the freezer which opens up and the vacuum that grabs the items with air pressure to bring them to be dispensed?

Just some food for thought.

By: David Hamilton

David Hamilton — Thu, 20 Nov 2008 09:08:15 +0000

Clever. For sheer Devil’s Advocate sake if nothing else, I might point out that care ought to be taken with the idea of darkening all unselected items. Consider the customer that wants to change their selection: Once they’ve chosen something, everything else becomes more difficult to see (assuming circumstances where the light levels within the machine would have a noticeable effect on visibility, such as at night).

By: Joshua Simmons

Joshua Simmons — Thu, 13 Nov 2008 04:45:24 +0000

That’s a superb vending machine design and I’ll be delighted the day I get to interact with something so sensibly engineered.

Thank you for a breath of fresh air in a topic, industrial design, that I don’t get to hear enough about!