Egg storage counter

Good day all,

I have these egg trays with space for 30pcs in each.

Ideally I would like to display online how many eggs I have in stock.

Was planning to start with one tray but might want to extend to 2-4 trays later on.

Big question, what sensors to use which does noe cost a fortune and can handle to be stored in a fridge.

Weight scale does not work as if there is a few grams difference on the eggs the count will be wrong on a tray.
Shape does also differ a little so how deep in the 'pocket' may vary with some mm.

That will not be the easiest project. Is it worth it?
I suggest paper held to the door by magnets, and a pen.....

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So I gather you stack those trays by rotating them 90°.

I'm with Railroader. :laughing:

Weight would probably be the easiest to implement, unless you are storing an extremely wide range of sizes of eggs. What is the minimum and maximum an individual egg can weigh?

Take a scale and a bit of AI and it should work.

Weight seems to be the likely winner, but needs to be explored.
What’s the weight range per egg?
The weight of the tray?
Possible contaminants… labels, dirt etc ?

If you can identify a margin of error, there’s probably going to be a ‘manageable’ margin of error… e,g +/- 1 or 2 eggs.per tray.

The next challenge is complexity - if weighing per tray, or a stack of trays… the error margin will multiply.

Another possible method is optical… at the time of storage and removal.
Count & verify with an array of opto sensors as each tray is loaded, then ‘remember’ the count.
Same when removing trays to keep a running total.

:blush: Probably the easiest but when people drive a distance to find a paper saying 0 eggs today and an empty fridge their not to happy.

This is a self served mini outlet

Guess I have to go with the weight then, error might some eggs but at least "easy and quick" to implement and will also show if there's an empty fridge...
Normal egg 70gram. Diff up to 20gram per egg

That’s a LOT of difference…
Aren’t the eggs graded by size before they’re trayed?

If using weight set an "alarm" level that is safe. One thought could be a camera and, on remote demand, receive a picture.

Maybe if you let go of the requirement to find the exact amount of eggs and say only approximate or the exact weight of remaining eggs, that would be good for everyone planning a trip. If the weight is near zero, someone will have to restock. Otherwise, give them an average egg/weight so they can decide themselves whether it's worth the trip :wink:

Maybe look at a different way of storing the eggs that make it easy to know if, say, a row is full - eg if in full boxes, each box with an identity tag, only sell whole boxes .
With what you have now surely you have completely full trays , with some spaces on the last one - so count full trays ( height of stack or whatever ) ... should give you eggactly the right answer (!)

Oh no, not another egg yolk!

Sounds like there is too much variation for weight to be reliable. The humidity in a refrigerator would make anything that is not sealed problematic, and any type of camera system would be subject to condensation or ice obscuring the view. A switch contact underneath each egg would work, but the entire assembly of switches would need to be well sealed.
Do people actually want to buy eggs individually? Packaging in at least half-dozen quantities would make things a bit easier.

Maybe work up an arrangement to trigger hall switches - egg presses magnet into switch range and, contact!  Encase the switches and connections in potting compound for the humidity issue.

Just a thought.

Is 70 the average weight or the median weight?

Do you have some egg weight data with which you can calculate a standard deviation?

Thanks a lot for the inputs, to answer some.
The weight i mentioned is not median or average it varies from day to day and tray to tray.

I do not need to know exactly how many egg is sold or is left but this is only needed for the "customers" to be able to see if there is eggs in the fridge before driving through town to get them.

I think then I go for a scale to get an approx amount of eggs.

Any suggestion on weight sensor capable of being inside a fridge.
Since this is a tray I assume i might need several sensors since it will not be balanced. (4?)
Weight of one tray might be up to approx 2.5 kg.

Sounds like the most practical, the approximate number sounds entirely appropriate.

Strain gauge. A little condensation on occasion should not be a problem.

With good design using pantograph supports, one at each end would do.