How to identify an object

Other Hardware Sensors
1

I have 8 objects that need to be placed in a grid. You are supposed to place them in an predefined order so a LED will turn on. I’ve read about RFID but those need a lot of pins on the Arduino and I’ve heard problems occurring when you connect more than 4 of them. Does anyone know a solution so I can detect if they are in the right place? (Without using a camera)

Edit: if I wasn't clear, i have 8 object that need to be placed in a specific order. I just don’t know how I can detect if an object is in the right place without using a camera.

2

Please post the actual text of your assignment, so forum members could have some idea of what you are supposed to do.

3

Can these objects have electrical contacts? (at least 2 contacts)?

4

Could you define the project .Do you need to identify the objects or you only need to place the objects in a certain order

5

Is there some specific difference between the objects, such as different shape, color, weight, etc?

6

Only in the right order

7

All the same, they are like wooden blocks. Same weight, color and shape etc. They are identical.

8

Rather not but i do want to hear what your idea is

9

How do you yourself determine that eight identical objects have been placed in the correct order? Or are you referring to the order in which they are placed down in the grid, not the order in which the objects themselves are arranged?

10

If you can use two contacts per object, I would use a 1Wire DS2401 device, in parasite mode, on each object.

Each device has a unique serial number, and by reading each group of 2 contacts, you can identify who is where.

11

The order in the grid, so block 1 needs to be in place 1 and block 7 need to be in place 7 on the grid

12

Hi @misterspikie ,

the solution highly depends on your specific requirements for "identifying an object"...

As @david_2018 already mentioned it would be very helpful if you give some more details about the application:

  • Is it required to identfy the individual object or just an object?
  • How will the grid be realized? Material, size?

So is it sufficient to know where the objects are place in the grid:

image

or is it required to know which object is placed at a specific position:

image

That makes a big difference for a possible solution.

Sorry, that overlapped with your post 11 ... So it is more case 2) ...

Could you post a sketch of the grid and its dimensions?

13

over the years there has been some work done to recognize chess pieces on a board.

this patent could give you ideas (but it's patented :slight_smile: )

14

Could you be more general?

15

Fascinating! How do you tell them apart?

16

the question is not to tell them apart from what I understand

It seems it's to ensure they are placed where needed on a grid and it's the order in which they are placed on the grid does not matter

17

Evidently, the OP can't be bothered to provide useful details.

18

he did in post 11

19

If you are happy, then I'm happy!

20

Too old to be unhappy about things like that :slight_smile:

(I give you we are missing grid size)

if OP can have some contacts closed when the object is placed on the grid then a simple keyboard matrix with diodes could do

MsPOe
MsPOe991×561 5.45 KB

(source)

ideas could be magnet detectors below each cell and a magnet glued at the bottom of the object or just two pins (like a jumper) mating with matching header on the other side to close the "switch" which would keep the object in place