hi to everyone i want to make a ir remote just like a tv but i want to send my own data . i got help from net and try circuit on this link "http://www.rentron.com/Infrared_Communication.htm " now after some trouble i succeed bt still hav a small range now can anyone help me that how can i increased my remote range. tv remote hav a lot of range with in a room and ir recieve recieved it from any direction with in a room and operate on 3 volt only what is a science in ir tv remote that only 3 volt give a room range
kindly help me i have need it urgent ......

 

Hello majoka
To increase the range, you have to increase the power from the IR-LED:s. Important is also that the IR- transmitter and IR- reciever wavelength are the same.

But the way to transmitt decribed at the site is not very efficient. It is enough to send a short puls for every positive and negative flank. This pulse can have a very high effect, the IR-LED can bee driven with several 10 mA:s. I don´t know if you can use the same reciever or you must design an own.

Gustav

 

i am using the same reciever and also try on tsop1738 but behavior is same i think that problem is on emitter side i used normal ir led can u hav any schematic to solve this prblm........

 

Have you tried using tip #2 at the end of the article you linked?

Tip #2: If you really want to crank power to the LED, try reducing the duty-cycle of the carrier to around 1uS, and using a very small (or no) current limiting resistor for the IR LED. You'll want to replace the 2N4403 LED drive transistor with one that can handle this power level.
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can u have a knowledge that how a tv remote transmit high power with just 3 volts its seem's to strange

 

The output is an IRLED. Vf is on the order of 1.5 volts, so there is adequate capacity for current through the IRLED to make it emit.

 

By reducing the size of the resistor in series with the IR LED, high PEAK currents can be achieved. A pulsed current of 300 mA would not be uncommon.

(3.3V - 1.5V) / .3 = 6 Ohms

At a 10% duty cycle the average current would be 30 mA for part of the time it takes to send a command. This further reduces the current draw as seen by the battery.

 

i change the duty cycle from 50% to 25% and i get a suitable range almost near to tv remote thanx to all dears