Proximity Distance measurement using IR LED and TR

[e_eja]

infrared phase distance

ir proximity detector is limited by it's light intensity, may be only for short distance betwen 0-3 mm, in order to be able dtect more long distance i suggested that the light is modulated like on remote TV with fast switching frekuensi and high current delivered to IR LED, thi is caused more light intensity and more distance could measured.
thanks

 

[artem]

infrared led distance

One method used is IR tape measurement substitute devices is to modulate the IR emitter with a sine wave superimposed on a DC level. The receiver picks off the sine wave and compares the phase with the transmitted phase. A calibration point is used to compensate for the time delay through the electronics.

I suppose (taking light speed into consideration) yor circuit based on phase shift must recognize 3 nano sec delay per 0.5 m distance .
Is there cheap way to handle such short phase difference measurement ?

 

[bilgekaan]

ir led sensor 38 khz oscillator circuit

http://www.junun.org/MarkIII/Store.jsp
they sell Distance Measuring Sensor from sharp accept international orders