line tracing using TSOP

k_ishan said:

Hi guys.........
i have tried TSOP-1738 alongwith IR led as an obstacle detector.......
its output goes low whenever obstacle comes in its range......it remains high otherwise.......
i think it can also be used to trace the line ......
i think its outout should go low on white line as IR light will get reflected from white and it should remain high on black line as IR light will not get reflected from black and it'll not detect black line as an obstacle
but in case of TSOP-1738 THIS IS NOT HAPENNING .........
CAN U PLEASE HELP ME........

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ericgibbs said:

hi,
The TSOP requires a pulsed emitter pattern for correct operation, not on/off IR line detection. datasheet.

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k_ishan said:

yeah, i know it ......................
i have applied 38khz pulses(square wave).........

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ericgibbs said:

hi,
Are the pulses of the emitter produced to this specification.? 10 to 70 pulses and a gap of 14 pulse periods.?

A continuous 38KHz pulse rate will not work, look carefully at this image

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k_ishan said:

I am not getting what is the BURST LENTH??????????/

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