How can I detect if an item has been placed in a box?

Hello everyone,

Let's say I have a shoe box and an item. How can I detect if an item has been placed inside the box.

I have come up with the following possibilities and I am looking for more and the best option:

Maybe an ultrasonic distance sensor? Maybe a SHARP Infrared Proximity Sensor?

Also I would like to not use a weight sensor.

Thanks

how about in infrared breakbeam sensor?

https://learn.adafruit.com/ir-breakbeam-sensors/overview

You need to tell us what sort of item and what size it is.

…R

Let's say I have a shoe box and an item. How can I detect if an item has been placed inside the box.

Open the lid and have a look.

Alternatively give it a shake and see if it rattles. Otherwise if the object can be any size and composition there is no way to reliably detect it.

You can measure the weight of the box before and after, although it may be difficult (near impossible) to measure things like feathers and anything lighter than a few grams.

However if the feather you put in the box is from Big Bird, you might still be able to measure it.

use an actuator and randomly dump the box out onto a tray. once you turn it over, you know it no longer contains solid objects.

the beam break might be easy. couple of mirrors and you could detect pretty small objects. If you sloped the bottom of the box to one side, then anything placed would (should) roll/slide to the bottom and break the beam.

the sonic could work too. kinda bulky.

the optimist side of me, I see the box as half full the pessimist side sees it as half empty the scientist in me sees it as completely filled, all the time.

dave-in-nj: the optimist side of me, I see the box as half full the pessimist side sees it as half empty the scientist in me sees it as completely filled, all the time.

The Engineer sees there's twice as much box as is necessary.

No the engineer says the box has a margin of times two.

It is the accountant that says it is too big.

And the economist says there is scope for expansion.

...R

And the Kleptomaniac says" What box? there never was a box there"

A pressure pad with microswitches?

Here's a crazy one: you could fill the box with water (yes, you would need to waterproof it so it doesn't get soggy :o ) and then measure the quantity of water displaced when the object is inserted.

In the absence of detail though, my money would be on infrared of some form. Either break-the-beam, or reflection. Reflection's easier since both "ends" of the beam are in one housing but it depends on the object's material and the distance.

All suggestions depend on how snug a fit the item is in the box, or and or how little if at all it can move around.

How about a false bottom and a micro switch?

Hi,

What is your application, and why can't you use a weight measuring device?

  • What is the container? (ferrous, non-ferrous, plastic.)
  • What is the object? (ferrous, non-ferrous, plastic.)
  • What is the mass of the object and container?
  • How big is the object and container?

Each on of these points will have an effect on what and how we answer your questions.

Thanks.. Tom... :)

Sorry for my late reply,

The box can not be toppled over, it is the size of a shopping basket and the items are 5cm x 5cm x 5cm foam cubes. So I am not sure if pressure/weight sensors will be efficient as the items are light.

It would have been mush better to say that in the first place.

I would suggest a row of LED beams on one side and sensors on the other 2.5cm up from the base spaced every 4cm along the side. Any broken beam equals something in the box.

bilalh: an item

bilalh: the item*s*

Item singular or items plural? Do you need to detect that there is at least one in the box, or know how many?

JimboZA: Item singular or items plural? Do you need to detect that there is at least one in the box, or know how many?

At least one item

If you use enough infrared heat, and the cart is open on the bottom, you can make sure there is always room for more.

bilalh: At least one item

well, since weight was ruled out on the very first post, and measuring displacement of foam that would float, not to mention that the cart would not hold water..... beam break will be the easiest and most productive.

My vote goes to a low-cost ultrasonic sensor.
Measure the difference in resonance, reflectivity, doppler-shift or whatever - or all at the same time!

That will ‘see’ feathers, bricks, water - almost anything that occupies any space within the .