Introduction: Coin Sorting Machine (Runs on Gravity)

Picture of Coin Sorting Machine (Runs on Gravity)

Tired of sorting coins manually? Coin sorting is a tiresome job. Let's make a wooden coin separator out of common materials! The sorter uses plain old gravity to separate the coins to their designated container. You know what that means! No more batteries!

What Made Me Build This?
Every time I go home from school, my pocket always gets full of coins. Once I arrive at my bedroom, I sort the coins to my 3 huge piggy banks. It's pretty tiresome thinking that I do this on a daily basis. So I thought of building a simple contraption that sorts coins by using gravity. The idea is pretty old, BTW.

Why Are There Only 3 Compartments?
There are six Philippine coins: 10 php, 5 php, 1 php, 25c, 10c, 5c. In my bedroom the 10 & 5 peso coins share the same piggy bank, both coins are the same in size by the way. The 1 peso coins has it's own piggy bank since it's the coin that has the highest quantity & it's pretty common. The 25, 10 & 5 centavo (cent) coins also share the same piggy bank since I barely get those.

Full Video Demo + Explanation:

Demo Video:

Step 1: Tools & Materials

Picture of Tools & Materials

I didn't spend anything since I have all the tools, parts & materials in our backyard (inventory).

Parts & Materials:
- MDF Material (your choice of wood)
- Bendy Straws
- 3.5mm Screws 
- Foam Board
- Super Glue

Tools & Equipment:
- 3.5mm & 6mm Drill Bit
- Jigsaw (Hacksaw)
- Right Angle Ruler
- 48" Metal Ruler
- Electric Sander
- Eye Protection
- Portable Drill
- Gas Mask

Step 2: Cutting the Wood Panels

Picture of Cutting the Wood Panels

Ok, start designing your box. Remember, since each country has a different number of coins, we probably don't have have the same number of dispenser divisions. But if you want to make the exact wooden box that I made, just follow the measurements below. 

Rear Panel = 9" x 6.5"
Bottom Panel = 9"x 3.5"
Side Panels = 6" x 3.5"

Use a pencil and a ruler to mark the cutouts then cut the wood with your trusty jigsaw. The 2 middle dividers should have a small rectangular nick. That small cutout will be the passageway for the coins.  

Step 3: Tips: Countersinking the Screw

Picture of Tips: Countersinking the Screw

Use a larger bit to countersink the screw. This prevents the screw from protruding over the wood's surface. This does not apply to flat headed screws. 

Step 4: Drilling Holes for the Screw

Picture of Drilling Holes for the Screw

I've now graduated from using woodglue to using screws & nails. I wanted to make this project as dry as possible so I used screws instead of woodglue. 3.5mm screws works best with 1/2" thick wood. Also, try to buy flat headed screws for you to omit the countersinking process. 

Step 5: Assemble the Sorter's Enclosure

Picture of Assemble the Sorter's Enclosure

After drilling all the holes as planned. You can now start to screw the wood panels to form the coin sorter's box.

Step 6: Super Glue the Straw (Coin's Path)

Picture of Super Glue the Straw (Coin's Path)

1st.)  Get a bendy straw and cut of the bendy area. 
2nd.) Drop superglue on the wood's surface.
3rd.)  Position the straw in a diagonal manner, enough to make the coin travel. 

Step 7: Making the Coin Sorting Mechanism

Picture of Making the Coin Sorting Mechanism
How Does It Work?
Try to experiment by changing the straw's gap. Certain coins should fall when the gap is to big for them other wise the coin will proceed to the next division. 

1st.)  Cut small fractions of straw, the size of the wall's width.
2nd.) Adjust the distance of the top straw from the lower straw. 
3rd.)  Apply small amounts of superglue ones you have finalized your straw's fixture.
4th.)  Get a small piece of plastic then glue it on the upper right part of the straw. This flap will guide the coins to the proper direction.

Demo Video + Explanation: 

Step 8: Silent Coin Drop Mod - Foaming (optional)

Picture of Silent Coin Drop Mod - Foaming (optional)

When the coins drop to their designated container, the sound can sometimes be irritating. I found a foam board from my Arts & Crafts supply cabinet. I've cut small rectangular foams to dampen the sound of falling coins. 

BTW you can add rubber feets to your coin separator.

Step 9: Adding a See-Through Wall

Picture of Adding a See-Through Wall

I ran out of clear acrylic so I substituted it with a thick piece of Acetate (OHP Film).

Step 10: Making the Top Cover

Picture of Making the Top Cover

I used an illustration board to cover my coin sorter's top panel.


Housedog (author)2014-02-18

It's very cool, but I don't quite understand how the straws sort the coins!

Maybe I'm having a bad brain day, but I don't get it.

If the straws were cut in half, and then had different size slits cut in them, it would make sense to me, but it doesn't look like that.

Can someone help me comprehend this please?

TeddyB9 (author)Housedog2016-03-29

The straws form a rail that the coin slides on. As long as the distance between the two straws is shorter than the diameter of the coin then it will continue to roll through the rail without falling because of the support of the stabilizing rail (top straw). When the distance between the straws flares to be bigger than the diameter of the coin then it will fall through the gap because nothing is stabilizing the coin.

rich.meyer.503 (author)Housedog2015-06-11

me too.

BTrey (author)Housedog2014-02-18

I don't the think the explanation is at all clear until you understand how it works. Then, magically, it suddenly seems easy and clear. The sorter works based on the height of the coin. As the coin rolls, the top of it leans against the higher straw but it can't fall because that straw us there. Just before the coin reaches the wall, there is enough gap for a coin of the right size to fall to the side. So the coin just rolls until there is a gap larger than the coin is tall between the two straws, then it falls.

ibwebb (author)BTrey2014-02-23

Thank you! I was in the same boat. I read it twice and still though I was missing something. Glad you answered! lol

Housedog (author)BTrey2014-02-19

Thank you.

Sometimes, some things just don't click!

Cometeer (author)Housedog2014-02-18

Here is a picture from the author's instructable.

There is a few mm of space between the top straw and the wood. When you insert a coin, it will roll along the bottom straw. The gap between the two straws increases as the coin rolls further along. Small coins will fall into the first box because it will fall through the gap between the two straws. Bigger coins can't fit through that gap, so they will continue to roll along until they reach a gap between the straws big enough to allow the coin to fall through. I hope this makes sense.

Cometeer (author)Cometeer2014-02-18

Did you watch the author's demo video? He explains is pretty clearly.

Watch this video too.

Housedog (author)Cometeer2014-02-19

I watched the authors video several times - it's too far away for me to see what is going on. Thank you for the lego video. It looks magical and unfathomable as well! Maybe I've had a minor stroke or something!

Remember those 3d pics you had to stare at while relaxing your vision, then all of a sudden it turned 3d? This seems to be analagous to that. Sometimes they would pop right into your perception, other times you could stare for minutes and still not see it!

Thanks for trying to help me.

YouNeverKnowItUntil (author)2016-12-15

What school do you go to where you are able to obtain so many coins in one day?

Arghus (author)2014-02-23

i built it on the moon but the gravity being lower than on earth where i suppose you built your sorter, it just doesn't work for me..

_soapy_ (author)Arghus2016-05-13

This should be fine at 1/6th gravity. Might need a longer ramp travel though.

IamNo0100 (author)2016-04-20

Hey guys,

Any suggestion about this idea 'Coin to Bill changer dispenser' where in coins are feed into slot and it'll changes to certain bill denomination( we're using 3 coin denomination and 3 bill denomination as well), any possible shop where we can acquire your suggested materials. Thanks in advance. :)

RenzA4 (author)2016-03-12

Nice project kuya! :) I think it can be upgraded into something more..... maybe an arduino coin sorter and counter?... can you please help me to build a coin counter using arduino? please :D I'm coinfused for the materials and sensors to be used for a coin counter.... :) proud Filipino here

Great Job... Iba ang gawang pinoy :)

jragasa (author)2015-06-22

CLEVER! Great job!!

Galing mo!

jragasa (author)jragasa2015-06-22

and yes, just to remind you. We do not have "cents" -- we call it "centavos"

Fab Muchada (author)2015-06-21

the upper straw regulates the coin sizes that's why the bigger coins go to the last division, the mid size coin goes to the second and the smaller ones goes to the first division.

sdesai1 (author)2015-06-21

Well its like. Coin rolls on bottom straw and gets dropped when it looses top side support of another inclined straw.

sakethasathvik (author)2015-06-21

Thats awsome!!

Firstdalek (author)2015-06-14

Wouldn't it be simpler to cut slits in the straw in the varrying sizes of the coins? That way, the bigger coins would simply eoll over the smaller slits. ? That's what I thought it was at first.

markw314 (author)Firstdalek2015-06-21

No. If you did that, then the larger coins could get caught in the smaller coin slits, the way a tire can get stuck in a pothole.

3DWulf (author)2015-06-12

Very nice low tech implementation!

Is it the curve of the straw that is making the coin lean toward the drop?

Thanks for sharing.

snobahr (author)3DWulf2015-06-21

Step 7 shows where you put a bit of plastic to guide the coin into a leaning-outward position, so it will drop into a void once the coin fits under the rail. One could, in fact, make this all wood, using a thin strip of wood for the track, and another thing strip for the guide rail.

mpintovsj (author)2014-02-28

Genial ! , muy buen proyecto.

ista rita (author)mpintovsj2014-06-07

I like it but i dont understand how its being sorted.

snobahr (author)ista rita2015-06-21

It looks like the coins are trapped by the straw on the bottom on the straws as rails. If the coin is small enough to flop out from under the rail, it will drop into that section's void, otherwise, it will continue to the next void. That's why the catcher at the beginning is put at a slight angle, to have the coins be in a position to fall out once the top rail no longer inhibits them.

ushuaia (author)ista rita2015-06-11

I think this was explained by one of the posters. The straws are lined up in such a way that there are going to be three holes, one small, one medium, and one large. The larger coins passes through the small hole, but since they cannot fit, will just roll again until the hole is big enough for them to pass through.

DaniloB1 (author)2015-06-18

Buenisima idea, gracias por compartir.!!!!, Very Good Idea, thanks for sharing...

pete.hohensee (author)2015-06-11

I'm afraid I don't get the point of this device. The great thing about modern coin sorters is that you can take a handful or jarful of coins, dump it in, and the machine does the sorting for you. With the device you have built you are putting in one coin at a time. Let's say I have three glasses. I pick up a quarter and put it in glass #3. I pick up a dime and put it glass #2. I pick up a nickel and put it in glass #1. How does your device have any SIGNIFICANT advantage over the glasses? Is it the tiny bit of brain power saved by not having to determine a quarter from a nickel?

jeanniel1 (author)pete.hohensee2015-06-13

It's more fun than sorting one by one - and it's ingenious by the WAY it sorts versus manually. Faster, too. When you use the machines that sort in the grocery stores, they take a percentage. Or for the battery-operated machines, you have to change the batteries, the mechanical parts fail and can't be replaced, and they tend to be bulkier, allowing less room for coins. Believe me, I've used all kinds of coin sorters!

pete.hohensee (author)jeanniel12015-06-13

Ummm... Jean... with this device you ARE sorting one by one.

jeanniel1 (author)pete.hohensee2015-06-13

Yes, I suppose a coin hopper could also be added - thinking beyond the stuck comment of hand sorting. Still more fun. Don't miss that part of the deal! No curmudgeon comments - just constructive comments vs judgmental ones.

pete.hohensee (author)jeanniel12015-06-13


Ever try to sort coins at 2 am in the dark when you are piss drunk? That senario aside, leave the kid alone. He engineered a suitable solution for himself and should be commended for his effort. If everyone just went out and purchased every available mass produced solution, no inovation would take place. Sometimes, reverse engineering is the precursor to inovation.

Well I don't see why coins would have to be sorted while I'm "piss drunk". A suitable solution? What problem is the solution for? And I'm not trying to pick on the kid. I just don't see what is useful about the device.

...and there was nothing useful about your comment. So why post it? In fact, I don't see anything useful about your life, so why live? Just be be helpful or encouraging with your comments, or don't comment at all.

Would you like a hug?

sure. I am always down for a good hug.

PopsicleGhoul made it! (author)2015-06-11

I made this today using laser-engraved cardboard and salvaged polycarbonate. Mine sorts U.S. coins and uses a similar principle to the differently-spaced straws. I posted more details to my blog ( and also made a YouTube video showing it in action:

The laser cutter I used is homemade. I have a collection of posts about how I built that here:

Mr AbAk (author)2015-01-08

Nice Ible ...

builder6100 (author)2014-12-07

That is an excellent idea!! I will be making this next weekend because I need to find time to run to the store for the materials. I'm just wondering what size mdf you used and what kind of wood you used?

thedugsh (author)2014-10-30

made it from the things i found inside my room. :D
Great work.. thanks!

pompogi (author)2014-09-23

very ingenius!!! mabuhay ka!! kabayan!! thats filipino ingenuity at its finest!!

pompogi (author)2014-09-23

magkano? it will be a good and fun way to teach my kids about saving money!

pucksurfer (author)2014-07-19

this is so cool

Maroga (author)2014-03-19

One question, would I be able to replace the straws with wood? That way it will look way cool!!

ASCAS (author)Maroga2014-03-19

Yup! It's up to you, it's your project afterall.

Maroga (author)ASCAS2014-03-20

Thanks mate!! Will it do the trick? Will I get the same sorting results?

ASCAS (author)Maroga2014-03-20

Yup, it actually depends on your positioning, but adding straws are much easier since you don't have to cut thin pieces of wood.

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