# Infrared Range - LED vs. Module

#### kapildevkumar a

Joined Jun 5, 2015
3
I have tried using an IR transmitter and Receiver. But its range was too small. How can a increase it(like that of in a TV remote)?

What is the range of IR LED ? By adding a high frequency carrier wave does its range(operating distance) change? If yes how(briefly explain)? What is the need for high frequency carrier wave?

#### wayneh

Joined Sep 9, 2010
16,398
Yes, modulating the carrier will dramatically increase range. The receiver can be set to be much more sensitive because it is rejecting noise that is not at the carrier frequency.

#### ronv

Joined Nov 12, 2008
3,770
I have tried using an IR transmitter and Receiver. But its range was too small. How can a increase it(like that of in a TV remote)?

What is the range of IR LED ? By adding a high frequency carrier wave does its range(operating distance) change? If yes how(briefly explain)? What is the need for high frequency carrier wave?
http://www.vishay.com/docs/82459/tsop48.pdf

#### Bernard

Joined Aug 7, 2008
5,555
What range do you need ?

#### kapildevkumar a

Joined Jun 5, 2015
3
In the Range of 10m. How a carrier wave increases its range

#### GopherT

Joined Nov 23, 2012
8,012
In the Range of 10m. How a carrier wave increases its range
It is not JUST the carrier wave that increases range, it is also a frequency-selective band-pass filter that makes the receiver much more sensitive. Without a carrier frequency, the receiver is very sensitive to "noise" (reflections, sunlight, electrical noise, ...) if you give the receiver circuit very high gain. Alternatively, with a carrier frequency, you can filter out all DC and all other frequencies of IR noise and look only for pulses of the correct frequency of IR, amplify with very high gain and, with that, get amazing range 5 to 7 meters, in daylight.

Two more things to consider to get that great range is to:
- use low angle IR emitter to concentrate the energy into a tighter cone.
- check the datasheet for maximum current at 50% duty cycles which may be quite a bit higher than the standard current rating to get brighter flashes and longer range.

#### wayneh

Joined Sep 9, 2010
16,398
Yes, modulating the carrier will dramatically increase range. The receiver can be set to be much more sensitive because it is rejecting noise that is not at the carrier frequency.