Coin Sorting- possible with photo/optical or laser scanning?

Thread Starter

jon_itmagic

Joined Mar 17, 2022
3
My apologies for resurrecting a 12-year old thread... I thought it was probably more appropriate / relevant to follow-up here, rather than start a new thread. But, if I'm wrong, I'm happy to do re-post.

I have a commercial requirement to source a machine that is capable of optically sorting coins on a conveyor system. I have no experience within this field, so am looking for advice / guidance as to who to approach for such a machine.

Thanks in advance.

Mod: link to old Thread.
https://forum.allaboutcircuits.com/...-optical-or-laser-scanning.116907/post-915639
 
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panic mode

Joined Oct 10, 2011
2,175
coins still have use today?
i don't remember last time i had one... ;)

you need to be more specific in what you are asking. what kind of volume we are talking about? 10 coins an hour? 10000 coins a minute? depending on situation maybe use mechanical sorting first to separate them by size, then use vision system to check them one by one or in batches.
 

MrSalts

Joined Apr 2, 2020
1,845
My apologies for resurrecting a 12-year old thread... I thought it was probably more appropriate / relevant to follow-up here, rather than start a new thread. But, if I'm wrong, I'm happy to do re-post.

I have a commercial requirement to source a machine that is capable of optically sorting coins on a conveyor system. I have no experience within this field, so am looking for advice / guidance as to who to approach for such a machine.

Thanks in advance.

Mod: link to old Thread.
https://forum.allaboutcircuits.com/...-optical-or-laser-scanning.116907/post-915639
My son made a purely mechanical, hand cranked device to do this when he was 14 as part of a STEM workshop. He beat out Juniors and Seniors and took home the $2500 scholarship first prize.
 

dl324

Joined Mar 30, 2015
14,704
Welcome to AAC!
I have a commercial requirement to source a machine that is capable of optically sorting coins on a conveyor system. I have no experience within this field, so am looking for advice / guidance as to who to approach for such a machine.
Your requirements are quite vague. Here's a commercial system that came up in a search:
 

MisterBill2

Joined Jan 23, 2018
12,440
A decent quality machine vision system can certainly sort coins passing by on a belt. the trick then is to mechanically separate them. I recommend a screen type belt and air jets to eject them into separate bins. You will also need an encoder to keep track of the coin's position, and some fast I/O. The big effort will be the software. A current PC will work well enough. And it will be able to handle many different coins, not just USA types.
And lighting will take some serious thought also
 
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Thread Starter

jon_itmagic

Joined Mar 17, 2022
3
Many thanks for your replies to-date, my apologies for not being specific enough with my requirements!

The coins will have already been sorted by denomination, so at the point when they're being run through the optical sorting system, they will all be of the same type.

I'm looking for a system that is capable of sorting a minimum of 600 / minute. I'd envisage it being a belt driven with some sort of hopper. As the coins progress along the belt, they'll need to be flipped so that both sides of the coin can be scanned. Scanned images to be compared against a database for sorting to occur. Sorting by date and potentially mintmark too. The machine would need a minimum of 30 output sorting channels / hoppers, ideally more.
 

MisterBill2

Joined Jan 23, 2018
12,440
600 coins a minute allows 100 milliseconds er coin, and at that level there will be problems with image recognition and analysis. So there will be some real issues with the time it takes. Image analysis is not even close to instant, even now.

And now another thing: That production rate, 600 coins every minute, seems like it must be a commercial application, not a hobby size of scale. My charge for commercial engineering services is far from free. But now you can know where the challenges will be..
 

MisterBill2

Joined Jan 23, 2018
12,440
Certainly they did! And certainly I forgot about that part. And certainly my response is correct. But now it seems that the actual application would be more towards somebody at a bank, or a very large business,evaluating streams of coins for valuable ones..
 

Thread Starter

jon_itmagic

Joined Mar 17, 2022
3
You are indeed correct, I have a commercial requirement for this. For clarity, I own a coin business & need to radically scale up the date sorting of coins.

My requirement of 600 coins / minute was a 'plucked out of the air one' - I chose that because that is the speed our current mechanical sorting operates at, which sorts by denomination. If the optical sorting element operated at 300, 200 or 100 coins / min, so be it.

I'm certainly not expecting anything for free! My first challenge is to find someone who is able to manufacture such a unit... I'm then happy to discuss costs.
 

MisterBill2

Joined Jan 23, 2018
12,440
You are indeed correct, I have a commercial requirement for this. For clarity, I own a coin business & need to radically scale up the date sorting of coins.

My requirement of 600 coins / minute was a 'plucked out of the air one' - I chose that because that is the speed our current mechanical sorting operates at, which sorts by denomination. If the optical sorting element operated at 300, 200 or 100 coins / min, so be it.

I'm certainly not expecting anything for free! My first challenge is to find someone who is able to manufacture such a unit... I'm then happy to discuss costs.
A system toprovide the sorting details requested will require a very high resolution inspection type of video camera and lighting. For that part you will need to work with a machine vision company.After an adequate image is acquired then there is the challenge of the image analysis software, which will certainly be complex. Probably this would be the major cost element in an expensive machine. The mechanical details will be the simple part of the system.
Unfortunately I am not in a position to be any portion of this project. But certainly the two big challenges are now made very clear.
 

Marley

Joined Apr 4, 2016
476
A modern industrial vision system and robot could easily do this task. But it will be expensive and slow as each coin has to be individually handled. It has the advantage that it can be programmed to accept any size of coin.
It is usually better to consider that there are only a small number of types of coin that you need to pick out. Coins have accurately defined physical characteristics: diameter, thickness, mass, density, etc. which are not likely change often.
Cheaper to design a mechanical sorter that uses these characteristics instead of optical appearance. this will likely work much faster too.
Example: roll them along a channel that has a slowly widening slot. Coins will fall through when the slot is wide enough into different bins. Then do further checks - weight, etc.
 

MrSalts

Joined Apr 2, 2020
1,845
The easiest way would be to guide the coins to a j-channel extrusion instead of a conveyor. That way, the coins will be perfectly positioned in front of a stationary camera and the camera can take a low-pixel count image of the small area to keep the image size (bytes) small and speed image processing. A 320x320 pixel image in 4-bit gray-scale with the full coin should be enough to identify the date. Lighting (angle, intensity, color, ...) is key to maximize contrast of the date on the coin.

A system like this can be simplified by not worrying about a flipping mechanism but, instead, simply let the face-down coins drop out and cycle through again. Eventually, they will all end up face up and get read. You'll just need to feed 1200 coins per minute if you need about 600 heads up coins per minute.
 
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