Pneumatic Can Crusher Awaits Your Command

A powerful robot awaiting for a verbal command to crush its foes might sound like something from a science fiction film, but now it’s a permanent fixture of the [Making Stuff] garage.  (Video, embedded below.) Thankfully this robot’s sworn enemy are aluminum cans, and the person controlling it with their voice isn’t a maniacal scientist, just a guy who’s serious about recycling. Well, we hope so anyway.

The star of the show is a heavy duty wall-mounted can crusher that [Making Stuff] built from some scrap steel and a pneumatic cylinder hooked up to the garage’s compressed air system. A solenoid operated valve allows an Arduino with attached ESP-01 to extend the cylinder whenever the appropriate command comes over the network. In this case, the goal was to tie the crusher into Google Assistant so a can would get smallified whenever one of Google’s listening devices heard the trigger phrase.

Note the ejector air line.

Obviously, those who’d rather keep Big Data out of their recycling bin don’t have to go down the same path. But that being said, having to give a specific voice command to activate the machine does provide a certain level of operational safety. At least compared to trusting some eBay sensor to tell the difference between an aluminum can and a fleshy appendage.

After crushing a few cans with his new toy, [Making Stuff] noticed a fairly troubling flaw in the design. Each time a can was crushed he had to reach into the maw of the machine to push its little flattened carcass out of the way. In other words, he was one bad line of code away from having one good hand.

The solution ended up being a new hose that runs from the exhaust port of the valve to the crushing chamber: once the cylinder retracts, the air exiting the valve pushes the crushed can out the rear of the machine and into a waiting pail underneath. Very slick.

Even if you’re not interested in the voice control aspect, this is a great design to base your own can crusher on. While it’s always a treat when a fully automatic crusher comes our way, we’ll admit the challenges of getting one to work reliably probably aren’t worth the hassle.

22 thoughts on “Pneumatic Can Crusher Awaits Your Command

  1. Since nobody buys theses cans anymore, the entire recycle system is a scam.
    You pay deposit, (Here in California) and take the cans to the recycle center. (Buy gasoline lately?)
    If, you have up to 50, un-crushed, you get your 5 cents back. Over 50, they crush them and pay you a reduced “Per Pound” money, the same as if you crushed them. Most of the centers have closed, and the cost to melt and create new aluminum is higher than new aluminum. (Go Figure) Did I mention it’s a scam?
    Criminals figured real quick, bring thousands of pounds of non-recycle fee cans to California, and profit.
    Sure, they did catch a few of the crooks, but the entire system has little of no oversight.

    1. Here it’s run by a federally regulated non-profit. You can either return up to a dozen at the store or take a pickup truck’s worth to the depot. Either way it’s 10 cents per container.

    2. Sounds like another reason not to live in California. Not only are we allowed to drink from cans in the rest of the country, but when they’re empty we can crush them down and turn them into the scrap yard for the current aluminum market rate.

      1. Same here in ny – you can do whatever you want, but if you want the deposit it has to be uncrushed – that’s the proof that nobody tried to return it twice. Or crush it and take it to a scrapyard, odds are on a given day it’s worth more than a nickel anyways. Up to you whether you want to make your money back or complain about minor inconveniences.

        I’d be more concerned with the fact that living in California these days seems to just about guarantee getting cancer, seeings as how you can’t buy anything there without a warning on the label.

          1. If only that barcode was at the bottom of the can, than that scanning problem would not exist… (if crushed properly). Properly might be a thing though. But this can be solved with a certified can crusher, available in the same store (another great way to squeeze money out of the customer).

      1. Labor costs and multiple steps in cleaning the scrap creates a low profit enterprise.
        An enterprise that can easily be upside down without careful oversight.
        Starting a “new” resource stream is difficult at best, and would require massive infrastructure.
        Can it be done? Yes, of course. Will it save the planet? No, of course not.
        Between engineers and bean counters, I don’t see a future in scrap aluminum.
        Have you ever seen government operation the turned a profit? Not in this state.
        Can the mafia turn a profit? Well, they seem to do Okay in the trash hauling business.
        How about you Alan, what say you?

    1. I have a habit of fidgeting with my empties occasionally, crushing them by hand. Too often, a sharp crease in the aluminum leads to a pinhole or tear in the metal, letting whatever is left of the beverage leak out.

      I imagine that an atmospheric crusher would work part of the way, then folds in the aluminum would just ‘pop’ the vacuum.

      1. I crush cans by hand too. With your hands on the top and bottom you twist the can as you crush it. No need to crush it all the way down. Just set it on the ground and finish the job with your body weight.

  2. Has anyone taken the time to train google assistant to react to blood curdling screams? I can’t imagine him having the wherewithall to shout “OK google, open can crusher!” in case of an emergency.

    Second thoughts, don’t! Anyone attacked by their own device with google assistant added to it is natural selection at its finest. Otherwise a very tidy build

    1. You know, at some point Google is going to become sentient due to the amount of processing power it controls. Could have happened already but that mind hasn’t cared to show itself or the fact has been kept hidden.

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