The circuit presented here is used to transmit and receive low frequency pulses using IR modulator and demodulator. IR modulator takes low frequency pulses as input. It modulates them on 38 KHz carrier and transmits them through IR LED as 38 KHz IR light. On the demodulator side IR sensor detects (receives) 38 KHz IR light. It demodulates this 38 KHz pulses and recovers transmitted low frequency pulses. One pulse generator is built using IC555 to generate low frequency pulses. IR modulator is also built using IC555 and TSOP1738 IR sensor is used as IR demodulator. 

The circuit presented here is used to transmit and receive low frequency pulses using IR modulator and demodulator. IR modulator takes low frequency pulses as input. It modulates them on 38 KHz carrier and transmits them through IR LED as 38 KHz IR light. On the demodulator side IR sensor detects (receives) 38 KHz IR light. It demodulates this 38 KHz pulses and recovers transmitted low frequency pulses. One pulse generator is built using IC555 to generate low frequency pulses. IR modulator is also built using IC555 and TSOP1738 IR sensor is used as IR demodulator.