can anyone help me with the detection of the presence of iron bar aproximately 12mm thick? the kind of bars you use for railways at our balconies.

i can't use a reflex surface at the other side of the railway and there is industrial enviroment (welding arc, dust, etc.).

 

Can´t you use an inductive sensor?
The diameter of the sensor gives you the detection distance.

Good luck.

 

thank you for your advice.

is there a possibility to tell me some common prices?? i may use a sensor from 5 - 10 mm no or nc with 2 cables no matter what size or shape...
thank you...

 

You can use any proximity sensor to detect iron/steel. The bigger the diameter the sensor the biger sensing distance it offers.

Check with any of the major electrical suppliers for what proximity sensors they have in stock.

 

Here is a perfect solution for this application.

This sensor uses a microwave beam, when the beam is broken by the steel bar, it outputs.

See this link:
http://www.wadeco.co.jp/sensorweb/pdfs/STSR2WG.pdf