Hello,
I'm looking for a sensor that I'm starting to think doesn't exist and hoping someone here can prove me wrong or might have another idea.
The application is a spool unwinder/winder (re-winder) machine. Picture a giant cassette tape.
The spools contain shiny cable (steel wire rope) 100% of the time.
90% of the time the spools are blue painted steel. The other 10% are unpainted wood.
The unwinder accepts spools/reels varying in outer diameter from 3ft/1m to 6ft/2m.
Inner diameter (drum/belly diameter) is also variable, exact specs unknown.
I need to detect when the spool in the unwinder is almost empty and stop the machine before it fully unwinds the spool and the loose end of cable goes whipping through the air.
If spool size were consistent I could use ultrasonic distance measurement to detect when the spool is almost empty. I have done this in the past with good results. But this time it isn't.
So my other idea was a color or contrast sensor which will detect the transition from the shiny cable color to the <not shiny cable color>. There are industrial color sensors which would work except for the distance requirement. They all need to be close-up to the object being sensed.
Ex1 - "normal" color sensor, range: 30-40mm
Ex2 - "long range" color sensor: 60mm
Ex3 - "super long range" color sensor: 150mm
The ideal position for the sensor is about 5-6ft (2m) from the spool. So obviously none of those will work.
I found this sensor which has a camera lens mount (arducam style) which seems to indicate that a telephoto lens could be employed to sample color from a distance. But there is a dearth of information provided about it and the more closely I look at it the more confused I am. There is an LED inside the lens mount area, among other components, and nothing is centered at the focal point. I Don't know how you would focus it without an image output to monitor.
I can always default to a machine vision camera if I have to, but I have a strong hunch that there is a simpler solution.
Any ideas?
I'm looking for a sensor that I'm starting to think doesn't exist and hoping someone here can prove me wrong or might have another idea.
The application is a spool unwinder/winder (re-winder) machine. Picture a giant cassette tape.
The spools contain shiny cable (steel wire rope) 100% of the time.
90% of the time the spools are blue painted steel. The other 10% are unpainted wood.
The unwinder accepts spools/reels varying in outer diameter from 3ft/1m to 6ft/2m.
Inner diameter (drum/belly diameter) is also variable, exact specs unknown.
I need to detect when the spool in the unwinder is almost empty and stop the machine before it fully unwinds the spool and the loose end of cable goes whipping through the air.
If spool size were consistent I could use ultrasonic distance measurement to detect when the spool is almost empty. I have done this in the past with good results. But this time it isn't.
So my other idea was a color or contrast sensor which will detect the transition from the shiny cable color to the <not shiny cable color>. There are industrial color sensors which would work except for the distance requirement. They all need to be close-up to the object being sensed.
Ex1 - "normal" color sensor, range: 30-40mm
Ex2 - "long range" color sensor: 60mm
Ex3 - "super long range" color sensor: 150mm
The ideal position for the sensor is about 5-6ft (2m) from the spool. So obviously none of those will work.
I found this sensor which has a camera lens mount (arducam style) which seems to indicate that a telephoto lens could be employed to sample color from a distance. But there is a dearth of information provided about it and the more closely I look at it the more confused I am. There is an LED inside the lens mount area, among other components, and nothing is centered at the focal point. I Don't know how you would focus it without an image output to monitor.
I can always default to a machine vision camera if I have to, but I have a strong hunch that there is a simpler solution.
Any ideas?