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
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Housedog1 year ago

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?

me too.

BTrey Housedog1 year ago

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 BTrey1 year ago

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

Housedog BTrey1 year ago

Thank you.

Sometimes, some things just don't click!

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.

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

Watch this video too.


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.

jragasa2 months ago

CLEVER! Great job!!

Galing mo!

jragasa jragasa2 months ago

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

Fab Muchada2 months ago

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.

sdesai12 months ago

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

Thats awsome!!

Firstdalek2 months ago
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.

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.

3DWulf2 months ago

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 3DWulf2 months ago

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.

mpintovsj1 year ago

Genial ! , muy buen proyecto.

I like it but i dont understand how its being sorted.
snobahr ista rita2 months ago

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 ista rita2 months ago

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.

DaniloB12 months ago

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

pete.hohensee2 months ago

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?

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!

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

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.

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!2 months ago

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 (http://sciencewithscreens.blogspot.com/2015/06/ran...) 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: http://sciencewithscreens.blogspot.com/search/labe...

Mr AbAk7 months ago
Nice Ible ...
builder61008 months ago
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?
thedugsh10 months ago
made it from the things i found inside my room. :D
Great work.. thanks!
pompogi11 months ago

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

pompogi11 months ago

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

pucksurfer1 year ago

this is so cool

Maroga1 year ago

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

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