Accurate Coffee Billing Through Reverse Engineering

If you’ve ever worked in a stingy office, you’ve become familiar with the communal coffee maker that runs on some variant of the honor system. There’s bits of paper, a coin jar shabbily sealed with sticky tape, and the routine note every six months telling people off for not paying for their daily brew. It all gets a bit much. Thankfully, if you work with [Fabian], it’s no longer a problem (PDF link).

The project forms the basis for [Fabian]’s thesis, in which a DeLonghi coffee maker is reverse engineered. This is undertaken with the explicit goal of properly metering the amount of consumables (coffee beans) used per beverage, to more fairly charge users depending on their brew of choice. This involves breaking down and understanding the coffee maker’s internal communications, as well as implementing a system to record and handle billing. For reasons of simplicity, [Fabian] decided that this should be handled using his colleague’s existing computer accounts. Easy!

It’s a highly academic approach to what we’re sure was a very stimulating project with lots of delicious aromas. Coffee’s a popular topic among hackers, that’s for sure – check out this roaster to take your game to the next level.


37 thoughts on “Accurate Coffee Billing Through Reverse Engineering

    1. When I ran the coffee pot for our small engineering group. the deal was:
      “A buck a week, all you can drink. If you kill the pot, make a new one.”

      We never ran out of money. The second part of the deal was always the hardest.
      I bought 2 lb cans of Chock-Full-o-Nuts, and no one complained. It worked out to pennies a cup.
      When the kitty started to overflow, I’d buy a box of donuts on Friday.

      2 lbs of canned, ground coffee is about $15 on Amazon, and the same weight of beans is about the same price.
      I’d be surprised if precise cost management is necessary. Maybe up it to $5/wk for all you can drink.

      Coffee, even the good stuff, is stupid cheap. Starbucks is making a lot of money for just that reason.

      1. I should note: my career as a coffee provider was in the 80s. Don’t think you could get away with $1/wk today, but I’m willing to be proven wrong :-)

        1. Probably could, but that would require you to buy the roasted beans in bulk and by that I mean the entire 50 or more pound bags and straight from the roaster…depending on the consumption rate, it might work.
          But if you’re not consuming it fast enough, the coffee looses flavor over time.

  1. I applaud the effort and love when things are over-engineered for their own sake! I understand that things in the academic community are for good reason different than the corporate / non-profit / idie working environment. I will make this somewhat controversial statement: people should not have to pay for coffee at work! Asking people to toss in a quarter or a buck here and there is short sighted, a penny-wise, pound-foolish way to skimp on a budget. If you want happy, productive people, just let them pour coffee without worrying about the cost of the bean (which compared to the fully-loaded cost of a professional worker, is really just in the noise).

    1. I agree. But in reality and working for a huge multi national, it’s different rules for different locations.
      Basically what they think they can get away with.
      When I travel I see different perks at different offices in different countries.
      Bringing it up with HR the response is essentially what I said above about getting away with it, only phrased in a slimy manner.
      And I agree it’s completely short sighted too, since the effect such a response has on the employees doesn’t exactly endear them towards the company, going above and beyond, and all that management speak guff we get every week.
      All because someone else is getting a freebie and we ain’t.
      Bit pathetic all around really.

      Anyway, great project. If we were allowed a coffee machine (actually not for health and safety grounds, seriously) then we’d probably have to bill it because people will argue about a few quid/pence and how so and so uses it more than them plus no one would ever clean it.
      They’ve just about beaten teamwork out of us these days.

      Another somewhat controversial statement: why just coffee for free? Why not (insert drug of choice) for free too ?

      1. Free coffee, free lunch, free gym. These are the inalienable deamnds round this neck of the woods.

        In the past, I’ve also worked somewhere that had free ice-cream and soft drinks (in lieu of air-con…), but someone started stocking their home larder, and that was then pulled.

      2. When I did it (granted, 30 years ago), it was because the used motor oil at the corporate cafeteria was too expensive and not worth it. Engineers run on coffee (and beer, but that was a bridge too far, explicitly verboten by the company) and we just set up a pot in the office area.

        There was a half-hearted attempt on the part of the Security department to shut us down, but we told them “no”, and they backed off. I think it was a safety concern, but we always unplugged the pot before leaving, so they really had no argument, since it was always attended (I think they wished they’d thought of it themselves). It didn’t hurt that our supervisors were all part of the coffee club!

    2. The thing is, that not everybody drinks coffee, so having it free of charge on company budget would be unfair…it’s the socialism vs libertianism all over again, different people place different value on things and services…

      Pretty sure that a system like this can be expanded to include a real billing system, that automatically charges accounts of people that willingly participate and use either an RFID card or fingerprint (both have reasonably cheap readers available).
      Even if the coffee is paid for by the company, the machine should still require an ID token before giving out anything, keeps the wasting and abuse to more tolerable levels…

      1. I am not much of a coffee drinker (I somewhat prefer tea, as I can find its consumable much cheaper).
        But, if my employer offered coffee for free, you can safely bet that I’d be drinking more of it!

      2. Not everyone does the same amount of work and thus deserves the same amount of coffee. Link the credit on the ID token with the lines of code written per hour over the last day.

        1. Shouldn’t that also be AI’d (did I just coin a term?) not only the # of lines of code but also subtract bugs from their compile and maybe give a bonus points for comments or documentation?

      3. You would think it is unfair, but I think the value is small enough to not matter.
        On the contrary, I think having smoke breaks is a bigger favor to employees, by my math a 5 minutes smoking break costs a company more than consumables for coffee.

        1. In Oregon smokers are still allowed some labor jobs, but usually their breaks are 10 minutes and smoking would require making it off company property and back. They would need to work for a small enough business that the owner is blue collar and has no professional managers.

          But jobs where you get enough of a break to do it don’t hire smokers. Smokers don’t even work in offices anymore. If you “smoke breaks” you would not be able to hire any white collar workers willing to work near you.

        2. when my ex-boss (ointed head variety) began to complain about my smoke breaks i merely pointed out that the cellphone junkies wasted a lot more time by taking private calls. Not to mention Candy Crush etc. That settled it.

  2. Considering the powers that be banned “sugar drinks” from the vending machines here, if they decide that coffee is too much for the budget, you really have to wonder how that compares to multimillion$ salaries vs us at the bottom.

  3. Ah, sorry, if your boss isn’t providing you with something to drink besides water you should change the office. Over here we even have our own bar where we can have a beer with our colleagues. On the house of course. :3

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