Cheapest way to make 3 LEDs blink a specific pattern ID

[mikeselectricstuff]

Without knowing what kind of lense is being used and what kind of field you want to capture the resolution and framerate aren't going to help. I also think that trying to capture blinking lights in a videostream is going to be very hard because you'll likely also need to recognise and track the object across several frames BESIDES detecting it in the first place. A high resolution and framerate can actually be a bad thing according to my experience with computer vision. Depending on the application a big size QR style encoding (possibly with color if lighting is good enough) could be a much better bet. It will be easier to make the tags (just go to a print shop and have them designed/made) and the computer vision system will be allowed to drop a whole bunch of frames without getting into trouble.

Just so you know, I've worked on quite a lot of image processing and visual marker recognition/tracking.
In this case, having such small surface and such a big range, it might not be the best guess.
I will try it soon for sure, but let's just stick to the main question about the LEDs if possible.

I already have a working prototype.
It can detect multiple LEDs with unique ID, using a standard cheap 1280x720 camera. Multiple time per seconds.
What I need is the "hardware part" (circuit / components)  and is there any way to crunch it to a simpler design, that would cost almost nothing to make.
How to design the most simple circuit that will be able to "blink" LEDs with a specific pattern.

If you are certain that LEDs are the answer, you already have a few potential answers - lowest-end MCU or ASIC, probably a COB assembly. No other solution will approach the all-in cost in the quantities you're talking about.
Possibly die-bonded LEDs if the optics work out - maybe die bonded LEDs on the PCB combined with an injection-moulded light guide to direct the light in the required directions. A moulding like this could also be used to do things like holding the battery, retaining the PCB etc.   
 
You want to be talking to the sort of people that make flashing LED badges & toys, but you do need to think carefully about the power issue in order to specify the design sufficiently well.

[nctnico]

Perhaps this question is better asked to a manufacturer of these kind of gadgets. There are too many variables where solution A is cheaper/better then solution B or vice versa. This also has to do with the production techniques available to a manufacturer and their experience.

[Someone]

Balancing a dice to the precision users expect while potting all this circuitry and a power source, you've got a long road ahead.

A high resolution and framerate can actually be a bad thing according to my experience with computer vision.

They need to be suitably matched, a camera might not even be the best solution if the transmitters are an open ended part of the solution (IR channel with CDMA or other strong telecommunications codings designed for mass transmitters). But the OP is drip feeding and says the camera is a fixed requirement. I'd be guessing at this point its validation for casinos and they want to leverage the existing camera infrastructure (at which point modifying the dice is insane).

Since the dice sit for some time while people observe the result it'd be a good candidate for a single frame (HDR exposures perhaps) at a high enough resolution to pick out dice face across the required field of view. Shoehorning this backwards to a camera specification is the wrong way to go about it.

[ebclr]

0.07 USD per piece

http://www.emc.com.tw/eng/database/Data_Sheet/8BIT/EM78P173N.pdf


https://world.taobao.com/item/536258162819.htm?spm=a312a.7700714.0.0.H5dZUO#detail

[jpauclair]

0.07 USD per piece

http://www.emc.com.tw/eng/database/Data_Sheet/8BIT/EM78P173N.pdf


https://world.taobao.com/item/536258162819.htm?spm=a312a.7700714.0.0.H5dZUO#detail

Wow...
This is looks amazing!
Did you try it? How did you find this one exactly?

[ebclr]

Just type MCU and ordered by price, and have several  supplier who can offer this product

https://world.taobao.com/search/search.htm?_ksTS=1475462058516_330&spm=a21bp.7806943.20151106.1&_input_charset=utf-8&navigator=all&json=on&q=EM78P173NSO14J&callback=__jsonp_cb&cna=Fb46ECHjIXICAbrne69e0gIM&abtest=_AB-LR517-LR854-LR895-PR517-PR854-PR895

[ebclr]

Also another option a litle more expensive 0.33 USD but western friendly

http://www.st.com/content/ccc/resource/technical/document/datasheet/4f/65/a3/d2/dc/56/46/d2/DM00060484.pdf/files/DM00060484.pdf/jcr:content/translations/en.DM00060484.pdf

https://world.taobao.com/item/39262418157.htm?spm=a312a.7700714.0.0.3aC6Uy#detail

[mikeselectricstuff]

0.07 USD per piece

http://www.emc.com.tw/eng/database/Data_Sheet/8BIT/EM78P173N.pdf


https://world.taobao.com/item/536258162819.htm?spm=a312a.7700714.0.0.H5dZUO#detail

If that's the price for a packaged OTP device, I wonder how much cheaper bare die would be.
 

[mikeselectricstuff]

Balancing a dice to the precision users expect while potting all this circuitry and a power source, you've got a long road ahead.

A high resolution and framerate can actually be a bad thing according to my experience with computer vision.

They need to be suitably matched, a camera might not even be the best solution if the transmitters are an open ended part of the solution (IR channel with CDMA or other strong telecommunications codings designed for mass transmitters). But the OP is drip feeding and says the camera is a fixed requirement. I'd be guessing at this point its validation for casinos and they want to leverage the existing camera infrastructure (at which point modifying the dice is insane).

Since the dice sit for some time while people observe the result it'd be a good candidate for a single frame (HDR exposures perhaps) at a high enough resolution to pick out dice face across the required field of view. Shoehorning this backwards to a camera specification is the wrong way to go about it.

It would certainly be cheaper to add a suitable camera.
If this is dice application, then for power management, some sort of motion detector should work well - probably something like a slightly loose ball contacting pads on the PCB. Just need to arrange the mechanics to work in any orientation. Doable but will need quite a bit of design & test work.

[amyk]

0.07 USD per piece

http://www.emc.com.tw/eng/database/Data_Sheet/8BIT/EM78P173N.pdf


https://world.taobao.com/item/536258162819.htm?spm=a312a.7700714.0.0.H5dZUO#detail

If that's the price for a packaged OTP device, I wonder how much cheaper bare die would be.

Not quite the same but I've seen sub-$0.01 for 4-bit mask ROM MCUs in >10ku (not including mask costs.) That one is pretty cheap for an 8-bitter with 1K instruction words.

[Xenoamor]

Bit of an off the wall idea but have you considered using an IR transmitter (it doesn't have to be an IR led though)? Something with a 555 timer connected to a LED and then you can just vary the components to change the frequency of the LED
you could then use the frequency to determine which device is which

You'd just be paying for a few resistors/capacitors and a 555 timer

[mikeselectricstuff]

Bit of an off the wall idea but have you considered using an IR transmitter (it doesn't have to be an IR led though)? Something with a 555 timer connected to a LED and then you can just vary the components to change the frequency of the LED
you could then use the frequency to determine which device is which

You'd just be paying for a few resistors/capacitors and a 555 timer

But that wouldn't get you any power management, and varying the frequency wouldn't give many ID options once you take the camera framerate into account

[dannyf]

Cheapest way to make 3 LEDs blink a specific pattern ID

How many EEVBLOG posts does it take to find the Cheapest way to make 3 LEDs blink a specific pattern ID?

[westfw]

Quote

It would certainly be cheaper to add a suitable camera.

What is "state of the art" for bar-code or QR code scanning via hi-def camera?  The smallest possible QR code apparently encodes 5 numeric digits...

[Someone]

Quote

It would certainly be cheaper to add a suitable camera.

What is "state of the art" for bar-code or QR code scanning via hi-def camera?  The smallest possible QR code apparently encodes 5 numeric digits...

Its not simple to define, you are limited in the resolution of cameras for a given field of view which places a lower limit on the resolvable detail. IR ink on a dice would be an improvement over just measuring the existing pattern, but its a cost trade off between the volume of consumables and the number of measuring devices needed. Solutions for customers measuring a few units with their numerous phones is radically different to a solution for a single location measuring millions of things.

[Wiljan]

Interesting article on Binking Led the LSI way
http://hackaday.com/2016/10/13/blinking-an-led-extreme-edition/

[dannyf]

that's too extreme.

so far, no one has presented a cheaper alternative than my swiping-leds-through-copper-stripes approach.

[alexanderbrevig]

[...]so far, no one has presented a cheaper alternative than my swiping-leds-through-copper-stripes approach.

I'd like to know how much it would cost to hire 40 people (given they manage to use one hand to swipe), have them in green suits and put in the time to make sure their intervals are OK to get detected by the CV algorithm.
To be cheap is not the same as being fuctional. The title says blink a specific pattern after all. 

[tszaboo]

[...]so far, no one has presented a cheaper alternative than my swiping-leds-through-copper-stripes approach.

I'd like to know how much it would cost to hire 40 people (given they manage to use one hand to swipe), have them in green suits and put in the time to make sure their intervals are OK to get detected by the CV algorithm.
To be cheap is not the same as being fuctional. The title says blink a specific pattern after all. 

Dont feed the troll.