Lime cutter/squeezer for an automated cocktail machine

I'm looking for a cheap, quiet and simple way of cutting limes into 1/8 pieces and for a way to squeeze (some) juice out of them.

I want to be able to dump like at least 50 limes into a big pipe or something and the machine should then be able to either cut or squeeze a lime and then dump everything in a glass.
I've been looking at these orange juice machines:

But these machines are at least a couple hundred bucks...

So I was thinking maybe something like this could be connected to a motor to automate it:

but how do I feed the limes to it and how do I remove the old lime when a new one should be squeezed?

For cutting the only idea I has so far was to use something like this and use a motor or something to make it push down on a lime:

But again it would be soo complicated to feed it etc.

I just can't seem to think of a good way of doing this.

(Ideally the squeezed limes wouldn't be dumped into the drink, but in a separate bucket. It wouldn't be the end of the world if everything got dumped into the drink though.)

The most important part to me is the automated lime cutting and dumping into the drink as I could buy lime juice in the first place...

You might start researching patents for machines and processes that do similar to what you want.

felic:
But these machines are at least a couple hundred bucks...

Unfortunately, the rest of your Post demonstrates all too clearly why those machines are expensive. This is not a simple task.

Wearing my Heath Robinson hat (Rube Goldberg for those on the other side of the Atlantic) what about placing the fruit in a piece of plastic gutter channel (the stuff that catches rain off the roof) with a slope so they slide towards one end. Use a servo to stop them, except when you want to release one. It could fall into a wide tube with a bottom so the slicer could be pushed down onto it by a DC motor driving a screw. After it is cut and the slicer has withdrawn then another servo could push the cut pieces off the base and into container.

...R

I have a small juicer. I put pieces of fruit in the chute and get juice and pulp and a lot of cleanup. It's not got enough motor for constant heavy use, those juicers cost a lot and still need the cleanup.

What you want is enough to keep a team of engineers busy for quite a while. It won't be cheap, quick or easy.

I've been thinking:

limes.png

Any thoughts on that? I'm sure there still are many problems with this design.

It may be more realistic to have to servo in the pipe hold the lowest lime against the wall until it's time to drop it:
limes2.png

The servo motor that blocks/holds the limes in the pipe would slowly open until a lime drops (which is then instantly detected by the photoelectric sensor) and could then instantly close again to prevent more from falling down.
The dropping lime would then slide into the cutting mechanism where it's detected by another photoelectric barrier. Which then activates the stepper motor. The stepper motor is attached to the lime cutter and has a screw shaft allowing it to move the cutter down/up by rotating. It then simply rotates until the cutter has completely cut the lime. Then it moves the cutter up (hopefully leaving the cut lime at the bottom, maybe trying to shake it off by moving it up and down quickly) then the servo below is activated causing the lime slices to fall into the drink.

Edit:
Maybe it would make more sense to fix the knife part of the lime cutter on the bottom and then the push thingy attached to the stepper motor so that the limes get pushed through the blades and fall into the drink. Another advantage of doing it this way would be that the servo doesn't have to carry the force generated by pushing the cutter down:
limes3.png

Edit2:
A more robust way of cutting the limes may be to use a potato cutter like this. It would also make it much easier for the stepper because of the lever.

Edit3:
How about this?
limes4.png

Heath and Rube would be proud indeed! :grinning:

I would consider using a robot arm. Nice and easy and plenty of examples.
Limes would be delivered via a piece of sloped guttering.
The arm would pick a lime and place it in the squeezer.
The arm would remove the squeezed bits after.

Steve

steve1001:
I would consider using a robot arm. Nice and easy and plenty of examples.
Limes would be delivered via a piece of sloped guttering.
The arm would pick a lime and place it in the squeezer.
The arm would remove the squeezed bits after.

Steve

Lol, I sincerely doubt that this would be "easy". While a robot arm would definitely be cool, I think there is a lot that could go wrong. Besides that a robot arm is too expensive.

Edit:
But if you know of a project that implements an ai that could recognize any lime and figure out its exact position and how to grab it using a robotic arm send me the link please.

felic:
But if you know of a project that implements an ai that could recognize any lime

Why would it need to recognize anything?

All it needs to do is move to the place where limes are, pick up whatever happens to be there and drop it at some other location.
...R

And thinking about it a bit more ....

The gripper could be made to be the squeezer as well. The gripper could incorporate a couple of metal blades to slice the lime, so it is ready for squeezing. Or maybe the end effector only needs a couple of studs to pierce the lime, before it does the squeezing.
The end effector would have to be something more substantial than the weak toy grippers that are readily available. It would have a geared motor, driving a screw, to do the squeezing.

I would think it is a trivial thing to get the arm to pick up a lime. You can do anything with Arduino!

Steve

Can you just buy freshly squeezed lime juice (with some pulp in it) and deliver measured doses as required? You would also need a stirrer in the tank to keep the pulp & juice evenly mixed.

"I would think it is a trivial thing to get the arm to pick up a lime. You can do anything with Arduino!"

Yea, I'm caught up somewhere between a trombone playing robotic arm and a four place flying carpet with a convertible top and surround sound.

"I think somebody should come up with a way to breed a very large shrimp. That way, you could ride him, then after you camped at night, you could eat him. How about it, science?" - Deep Thoughts by Jack Handy

Lime falls onto two rollers spaced so the lime will be supported by both. The motorized rollers turn causing the oblong lime to align its axis with the rollers' axes. A robot arm with a gripper like the orange slicer, upper left

moves and enclosed the lime along its axis. Grip the lime. Gripper positions against a solid surface. Piston/screw jack/whatever drives a set of eight knives into the lime (think hunting broadhead)

https://www.basspro.com/shop/en/slick-trick-standard-100-ss-fixed-blade-broadheads

Gripper moves and dumps sliced fruit into hopper. :smiley:

dougp:
Lime falls onto two rollers spaced so the lime will be supported by both.

That brings to mind something I had overlooked - the fruit must be oriented correctly for slicing. I can't recall ever buying a lime but from looking at them in the shop many are nearly spherical. It's easy for the human eye to spot the ends - maybe not for a machine.

The $200 machine looks like better value with every Reply. :slight_smile: And the business of being able to clean the DIY machine to food standards hasn't even been considered.

...R

How about somehting like a hotwheels booster. I'd just replace the motor with a 50000rpm motor and simply let the limes shoot through the blades. :smiley:

But in all seriousness, I think the biggest issue is having a big box of limes and making sure they arrive at the cutter.
With pipes there is the issue that it will jam at some point. And a robotic arm that could reach deep enough into the box would be too expensive and I think think that grabbing a lime with such an arm would be a very difficult challenge. I mean the arm has to understand when it needs to squeeze its fingers between a bunch of other limes to grab one and it also needs to understand that it can't just randomly stick the arm into the box potentially puncturing a lime while trying to grab one.

In my opinion cutting the limes in the correct orientation isn't really important. It would however be nice if it would only drop 1/2 or even 1/4 of a lime per drink because a whole lemon is just overkill and I think I'm going to use lime juice in addition to that anyway. So the lime pieces in the drink are really just for the looks.

Orientation is probably the hardest part of the contraption. If you don't care about that, it's a lot simpler already.

The other problem is the hopper: get one and only one lime to go out. Your servo solution won't work reliably, I'm sure. Dropping one and hoping the next is slow enough that you can stop it? Not a good idea. You need a way to get one and only one lime into a container, and then move that one lime to the cutter. When it's on the blades it's a matter of pushing it through, that part should be easy.

Such hoppers won't be simple, as the limes are different size. Maybe something like a conveyor with a cup big enough for one lime, too small for two? With some mechanism to hold back the second lemon without damaging either?

Next problem that I haven't seen touched here would be hygiene. The most appropriate material for a machine like this is stainless steel as it can be cleaned quite easily. It's also hard to work with. You'd have to make sure your build does not have any nooks and crannies where remains of lime can get stuck in, and start rotting.

So I've bought this cheap stainless steel potato cutter and I tried to cut a lime with it. It cut about 2mm deep into the lime, then the grid just bent. Fortunately there was a second cutting grid in the box. I forcefully ripped out almost the entire grid, but leaving a crosshair in the middle, so it would cut the lime into quarters. It may have made it 3mm into the lime this time, but then it just broke.

Also, limes differ in sizes quite vastly. Sure, some of them are pretty spherical, but a lot of them are more shaped like lemons. And the skin of the limes I got was incredibly hard and thick.

Sounds like such a typical case of back to the drawing board!

Just wondering (you apparently didn't get to that point): you apparently have to put a lot of pressure on that lime to get through. Won't it simply burst open on the sides and flatten instead of being cut nicely?

Probably the limes need a sharp blade and a sawing action - I think that's how a person would cut them.

Potatoes have a very different consistency - the skin is irrelevant and the they are pretty much solid.

...R

Robin2:
Probably the limes need a sharp blade and a sawing action - I think that's how a person would cut them.

Or band saw or circular saw.
Gonna be tricky to cut it in fours that way.