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I m making line follower bot using sensor-(IR RX and IR led). Here is my Circuit for IR tX IR TX circuit Circuit for rx rx

This both circuit are working properly my problem is IR Rx not receiving signal continuously it receive for 5-8 then it stop receiving even ir led continuously transmit.once again if you start from first it work after few seconds behave same it wont get any signal

Also i tried with different manufacturer ir rx it behave same but receiving time will very for each ir rx check out this 4 different ir rx all are 38khz frequency enter image description here

My ir led tx circuit will generate nearly 35 khz so i tried changing R2 value 18k but it behave same

How to fix this problem can anyone suggest

also i noticed that i m using 50-percent duty cycle with 38khz in tx side is it impact if i go for 90 percent duty cycle.How it is different from 50 and 90 percent duty cycle while same frequency what behave it changes

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Your IR receiver Q1 is upside down. You need to swap the collector and emitter pins. Current flows from positive to negative in the direction of the PN junction arrow.

enter image description here

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This type of receiver is optimized for IR-remote signales. It uses an AGC (Automatic Gain Control) to eliminate background noise. To be able to distinguish between the signal and the background noise, the singal must not be continous, it must be modulated (on/off), for instance 1ms on / 1 ms off. (This is on top of the 38 kHZ modulation.) If it is continously on, it will at first be recognised as a valid signal, but after a short time the AGC will kick in and the signal will no longer be recognised (at least not reliably).

enter image description here

So, you need a second 555 to key your IR signal. At the receiver you already have a crude integrator (C1), that might be enough to bridge the gaps in the transmitted signal.

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