Looking for suitable sensor

[sujit_51]

Hello
I want to sense transparant polypropelyne sheet which will activate my control circuit.

I have tried with capacitive proximity sensor but it didn't work.

Can any one please suggest suitable type of sensor so that it gets activated or deactivated when transparant polypropelyne sheet is present near the sensor.

Thanks.

sujit_51

 

[Sebi]

A reflective infrared?

 

[zevon8]

How about an ultrasonic proximity sensor?

 

[bloody-orc]

it all depends on how far you want to sence it. if it is more than 30 cm away then the most relyable thing is Ultrasonic. I dont know about IR cause it is transparent material and the IR signal reflected from the sheet may be to weak cause most of it will go through the sheet.

 

[tansis]

Sujit , can you tell us more ?

are we dealing with a flat sheet on a conveyer ?
is the plastic hot ?
How big is the area of this sheet , what thickness?
How fast is it moving ?

Often the simplest solution is a mechanical switch...

but ultrasonics could do the job , an optical system could be used if circumstances permit.. think refraction not reflection

Two other methods come to mind , first is the use of a theramin circuit
[google for "theramin vision"] this is a longshot but it might well work the other is to use a radioactive isotope coupled with a gieger detector ( often used in paper mills to measure and control thickness )

 

[sujit_51]

Suitable Sensor

How about an ultrasonic proximity sensor?

Dear Freind,
Thanks for responding to my querry for sensor.

Please suggest suitable type no and make /source of the sensor to sense transparant polypropilyne sheet.

You indicate the website from where I can pick suitable sensor.

Thanks.

sujit_51

 

[zevon8]

Try https://www.google.ca/search?hl=en&q=ultrasonic+sensor&meta=