The 555 is total crap to output a good 38khz signal. A much better alternative is a schmitt trigger inverter oscilliator with very low tolerance parts.
Most likely, because the IR signal is way too weak. Is this giving off a constant 38khz signal? if so, I would drop that massive 2.2kohm resistor down to 330 ohms for a much brighter signal display.
hook up a transistor's base to the output of the 555 and put a small resistor across the LED or Base? I just told you one way, you dont need any more than the 555 is giving you! the 555 can output about 200ma! That is killer for a LED!
The 2.2k resistor in series with the IR diode limits its current to about only 1mA.
If the resistor's value is decreased to 30 ohms then the current and brightness is 50 times higher. If the duty-cycle is reduced then the current could be increased much higher and the 555 could drive a transistor to supply it.
The TSOP IR receiver IC reduces its gain if the 40kHz IR is continuous to reduce its sensitivity ti interference from compact fluorescent light bulbs. The 40khz IR should be modulated in bursts of data with a pause in between.
is there any mistake in the values of R and C used in my transmitter ? i mean for producing a 38kHz.... if there is a mistake kindly send the correct values
If the parts values are exact and if the pot is set exactly halfway then the frequency is 41.9kHz.
I don't know what tolerance the parts have so the frequency will be different.
Adjust the pot so the max amount of signal is received.