How to detect a sponge ball passing by in a transparent Acrylic pipe?

[thomas_u]

I would like to use a camera or sensor to detect the existence of sponge balls passing by in a transparent acrylic pipe. The ball size is in the range of 12mm to 17mm and the speed of ball can be up to 1m/sec. Suggestion of what kind of camera or sensor and NI hardware are suitable is very much appreciated.

[Ben]

Check with "Keyence". They may have something that will work, but brace yourself, challenges cost $$$.

Another quick thought;
Did you concider listening for them? If you put a speaker generatin a steady tone on one side of the pipe and you press your ear up against the other, can you here the difference when the spounge ball passes?

Ben

[gog]

Have you thought using a light beam passing trough the pipe and detected at the other end by a photo detector. I think you would be able to easily detect when the ball is "cutting" that beam.

[Al_S]

If you're willing to design and build some hardware, how about a cheap photo-sensor (photo-diode or photo-transistor) and a simple light source? You can find sensors from Fairchild, Honeywell, Omron, Optek, and probably a bunch of others.
A lot of these sensors act basically as a switch: they conduct when they see light. Connect one side of the sensor to a pull-up and the other side to ground and check the output at the junction of the pull-up and the sensor. You'll get an inverted output: when it sees the light, the 'switch' is on and the output is low; when the ball blocks the light, the switch is off and the output is high (pulled up).