is the GP2D12 infrared sensor A form of transmitted beam/thru beam sensor???

[fantabulous68]

Im building an infrared liquid level detector using the Sharp GP2D12......

Photoelectric sensors are available in a variety of modes including:

* Infrared Proximity (Diffuse Reflective)

Proximity type photoelectric sensors detect the light reflected by the target itself. Proximity photoelectric sensors are preferable for general purpose sensing applications, particularly where the detected object is only accessible from one direction.

* Transmitted Beam (Thru-beam)

Transmitted beam photoelectric sensors use separate infrared transmitters and receivers. Objects passing between the two parts interrupt the infrared beam, causing the receiver to output a signal.

IS IT ACCURATE TO STATE(using the GP2D12)

An Infrared sensor is a form of a transmitted beam sensor,

if the above statement is TRUE:
Transmitted beam sensors are not suitable for detection of translucent or transparent liquids. They suitable to detect opaque liquids. My project does not work accurately with water. It works well with opaque liquids but my lecturer wants it to work with water as well. But water absorbs the infrared light. The IR light cant detect the surface of water well, it detects the bottom of the container resulting in in accurate liquid level measurements.

Grrrr i want it to be true I know the GP2D12 works on the diffuse reflection principle but is it a form of thru beam/transmitted beam?

 

[jpanhalt]

IS IT ACCURATE TO STATE(using the GP2D12)

An Infrared sensor is a form of a transmitted beam sensor,

No, that is incorrect. Your sensor is a reflective type.

But water absorbs the infrared light. The IR light cant detect the surface of water well, it detects the bottom of the container resulting in in accurate liquid level measurements.

Those statements are inconsistent with each other. The water DOES NOT absorb all of the infrared light. Thus, a large portion of the light, that is light that is not reflected from the surface, passes through the water and reflects off other surfaces, such as the bottom or sides of the vessel. Under some conditions, light reflected from the solid surfaces is more intense than light reflected from the liquid surface. It is then interpreted by the sensor to be reflected from the liquid surface and is ONE of the reasons you are getting result that vary.

I know the GP2D12 works on the diffuse reflection principle but is it a form of thru beam/transmitted beam?

No, it is not thru beam in any sense. "Diffuse beam" seems like a misleading description to me. Your detector responds to the reflected light from a focused beam. If the reflected light were extremely diffuse, it would probably not work.

John

 

[fantabulous68]

Thanks Jpanhalt.....
GP2D12 is based on reflection and triangulation principle.................


btw Ultrasonics are best suited for detecting clear liquids