Count Revolutions of Needle on Water Meter

[jon_mcbee]

Hello,

A coworker is working on a project where he has to count the number of times a needle makes a full revolution on the face of a water meter.  This meter looks similar to the electic meter you have on the side of your house.  It has a needle that moves clockwise and increments a counter  with each revolution.  We are working on a calibration bench for this type of meter and need a way to count the number of revolutions of this needle on the face of the meter for different flow rates.  There is no analog or digital output from the meter so this has to be done visually.  Does anyone here have any suggestions on hardware that we could buy that can count revolutions  visually?  He asked if I had any ideas, and my idea was to post here and see what the knowledge base has to offer.  Thank you in advance for any suggestions.

Regards

[Anbu_Soliton]

A machine vision camera could address this need. You can interface the camera through LabVIEW and write a custom vision algorithm to keep track of the number of revolutions. I could suggest further if you could give more information about where this application is going to be used.

[muks]

Why do you want to use a camera. You can do it using a optical sensor.

[jon_mcbee]

What type of optical sensor are you thinking of?  This is a water meter calibration setup and it will be in a wet environment, not underwater but subject to moisture.  I think the ideal solution would be to use an optical sensor, but I don't know what is out there that would fit the bill.