Count the number of objects

Hey Fellow engineers,
I have a problem in which i need to count a number of pre made number of ping pong balls automatically.
I'm able to place anything in the balls, and not allowed to use image processing.
My initial thought were to use RFID, and i came to realize this is very unreliable and expensive.

Any thoughts ?

Thanks
Shimi

weigh them

I am hoping to find a more generic way, still sounds interesting thanks

Hi Shimi..
I attached a diagram of a simple counter circuit so you could have an idea on which direction to take..
There are many circuits that you could make using counters with micro controllers and maybe flip flops..
let know what you want using my website links and i will try to help you.

First off, please proof read your posts before posting them:

bq). count a number of pre made number of ping pong balls

Is rather confusing -- the assumption is that you want to count ping pong balls and your post contains a typo, but I don't like to assume, so what does "pre made number of" mean?

Also, where are these ping-pong balls, in a bucket, a tray, strewn about a yard, in the stomach of a cow? More details, please.

Are these ping-pong balls going to be _used_ as ping-pong balls, or for some other purpose (thus would putting something inside the ball not affect the target purpose)?

And on a broader scope, what are the circumstances for counting? My first thought was counting them as they pass by on a conveyer belt -- again, details please.

Drop them though a pipe and add a gate at the top OR inside the pipe to allow fall though stopping each ball as one enters the pipe

You might use a solonoid as the gate centralised inside the pipe The pipes diameter needs to be slighty larger than the balls external diameter

Use a micro switch or infra red beam to count them and attach this to a micro with bcd display counting number of balls

You might whish to adapt some type of funnel using compressed air which suspends the ball in the funnel before allowing the ball to drop through the pipe

Think of a toy that you might have played with as a child to implement this counting mechanism that suspended the ball in mid air

This may very well be a twin gate affair one to stop at the top and one two release at the bottom of the pipe which is mounted upright or at some angle of inclination regulating the speed of travel down the pipe

ONE BALL ENTERS ONE BALL LEAVES

NOT MAD MAX IS IT THUNDERDOME. , "whoops "

Or is it let me see Pinball wizard think of how the old pinball machines work and then you could be on the right track

I think it might be much simpler. If the balls were loaded into a funnel or a tapered ramp with a ball sized hole in the bottom then a simple photocell, a photo transmittert and detector (A QSE113 and QEE113 for example) placed off center as the balls left the bottom. Placed correctly the pec output would be on half the time andf easily counted by a simple microprocessor, or something like it. No moving parts.

Yes roughly what I suggested my concern was counting to many balls, two or more and counting falsely, hence I suggested some type of mecbanical gated affair to control this

Youve got the general idea though

If you want help with coding or design on the electronics side shout

Need to know maximum count
How big a display you want
Typical operating voltage or supply voltage
IF a buzzers got to sound or visual flash once maximum number reached , whatever you have in mind let me know

I like little projects like this besides which it gives me something to occupy my mind with I cant stand having nothing to do with loads of promises etc So im not waiting for the world to answer Any way im fed up with this story and fed up with being. P**ss poor broke I fancy a shot at this with some interested people who want to get on in life

I fancy attacking this and creating jobs How about you

And of course there are other ideas that spring to mind here already making this a little more fun and a comercial enterprise

Thats if you fancy the idea of working with me and share the same ideoligy

If your answer is yes then your talking to the right person
Leave that with you to think about

Just for the sake of having my hat in the ring (as premature as it is):

How about a few esoteric _solutions_:
* Fill the balls with a noble gas such as Neon, Argon, Krypton, etc, and then have them roll through an intense high frequency electromagnetic field so they glow (red-orange if Neon, blue if Argon, green if Krypton) and detect the color with a tuned photo sensor.
* put them in a container, shake the container while monitoring the sound of the balls hitting the sides of the container -- essentially taking the "temperature" of the vibrating balls. Perhaps there is a consistent enough relation between the noise level (or pattern) and the number of balls within.
* Roll the balls over an edge so they land on a slanted target (that causes them to bounce away from the target and into an isolated bin and use a microphone detect the sound of the balls hitting the target (and count the "hits")
* Fill the balls with a gas that responds to MRI and then use Fourier analysis to count their spacial positions.
* Have the balls roll, single file, between a pair of metal plates and monitor the capacitance change.
* Introduce a small amount of hydrogen into the atmosphere within the balls and use a 1420 MHz pulse to stimulate emission from the balls which is detected with an array of antennas around the ball container.

Funny man I am laughing though just about nutcase
Merry xmas steve all the best hopefully a far better new Christ I hope so anything got to be better than the last five years weve had Come to think of it the last 20 years

Shear flipping hell

As you said that you can place anything in the balls, so put a small metal ball ( like ball bearing balls) inside and count the ball using metal detector.

intresting