Object detection sensors

[dominator]

hi , i am in search of a sensor that would detect object like small parcels moving on a conveyor belt. i am not sure which sensor to use. I am not interested in IR sensors and i am finding an alternative for it. some body gave me idea of a tachometer but i couldn't find the related information about it. can u tell me which sensor is best suited for this practical and also its details as well. thanks.

 

[3lectrokid]

how about ultrasonic sensors that emit a pulse and read how long it takes for it to echo into the receiver and if the echo gets quicker it will trigger somthing

Ultrasonic sensor - Wikipedia, the free encyclopedia

here is a circuit for an alarm
Ultrasonic Alarm (1)

google ultrasonic alarm for more circuits

 

[dominator]

Sir, basically my objective is that an object like a parcel is passing and i want to detect its presence. like you can say that it crosses a laser beam and i get a signal on my computer that an object has just crossed the sensor like we see in banks that at night if some body crosses the boundary restricted an alarm is on and a signal is sent to relevant people.

same is the case here. i am mainly concerned with the signal that i am going to receive when the objects passes through that sensor. i hope you get my point.

 

[3lectrokid]

is there any reason that you dont want to use infared.

 

[Externet]

What you want is multiple oriented barcode scanners. Parcels will need to have them attached if you want identification of the item. Sort of a supermarket register scanner on a conveyor belt.

A laser pointer beam interrupted by the parcel can also detect its passing. The sensor is a simple phototransistor, and industrial electronic supply stores have a bunch waiting for you.

 

[dominator]

what is the operation of a photo transistor and how does this thing work??
give me any link or source to get information only related to this sensor and also its practical applications.

 

[dominator]

is there any reason that you dont want to use infared.

sir actually the ac motor of conveyor belt is causing difficulties to operate the IR sensor efficiently and is causing problems.

 

[mneary]

Since the motor is not likely a source of infrared interference, the problem "caused" by the motor will be common to all forms of electronics.

Whether your circuit is optical or ultrasonic, your circuit will need to be properly designed to control external noise.

 

[StudentSA]

I would like to suggest to you, dominator, to use a simple Infra Red transmitter and reciver.

This would certainly be the best solution as it is dirt cheap. I have actually done a project of this nature in campus and can find the report for you tommorrow if you are interested.

How is the AC motor causing difficulties?

 

[dominator]

StudentSA, i am interested in the report. it would be good that if i get complete information regarding IR sensors. i want to make an IR sensor of my own and would love to test it on the conveyor instead of buying a fabricated IR sensor which is very expensive. so a circuit diagram of IR sensor and related information might do the trick.

AC motor is actually causing fluctuations and due to earthing problems the sensor does not work properly. i think a proper insulation of the IR sensor is required from the conveyor belt in order to get efficient results.

also do u have any idea about PLC ???