InfraRed transmitter

Thread Starter


Joined Mar 29, 2016
Hi guys, I'm Very new at Electronics and Electronics circuits.
I'm trying to create a Matrix with high power InfraRed transmitter.
I have two issues:

1) How to calculate the wave-length I need to my InfraRed transmitter While I know the this:

"Each pulse is turned on and off at a frequency of 38kHz"

2) How to choose a high power InfraRed transmitter, I have seen many types, My needs are:

a) Same wave-length as I will caculate from the frequency.
b) I need a transmitter that can transmite to long distance as much as he can.
c) I don't mind to spend 15$ for one transmitter as long its good!
For example:

Power: 10W
Current: 900-1200mA
Angle :125 degrees
The radiation power: 900-1000MW
Working temperature: -20 degrees ---+70 degrees
Storage temperature: -20 degrees ---+80 degrees


5W high-power Infra-red
Wavelength :940nm
Forward Voltage:1.8-2.4v
Forward Current: 1000mA
Lens Color : Water Clear
Viewing Angle: 120-140°



Joined Oct 29, 2013
Never take anything personally online. The guys above can actually be quite helpful!

Here is a nice explanation of how IR tx and rx work, and schematics for a couple of commercially available (amazon) build-it-yourself kits that actually work really well. This should get you started with figuring out how things work.

When you buy your IR transmitter and receiver devices, they will list the frequencies that they operate at in the data sheet. Just get matching parts. Sometimes they're sold in pairs. To send it a long distance you're just going to have to figure out how to basically make a good flashlight. Lots of LEDs and maybe a reflector.


Joined Mar 24, 2008
You give attitude, you will get the same back. You now have the full attention of the moderating staff.

A Note About Being Civil

To answer your question, it is generally not that critical. You can look up on the datasheet of the component what their peak emissivities and sensitivities are. If you are intimidated by datasheets you will need to practice reading them, possibly posting the datasheets asking where the data you want is located. In most cases it is pretty obvious if you study them.

One last note, if you feel you have been insulted use the report function. Responding in kind only gets you into trouble.


Joined Aug 1, 2013
Accidentally hit send after the inside joke and before the real response.
1) How to calculate the wave-length I need to my InfraRed transmitter While I know the this:
"Each pulse is turned on and off at a frequency of 38kHz"
You might be confusing two different frequency/wavelength concepts, the frequency of the emitted light and the frequency of the digital signal that is modulating the light. These are not directly related. That is, a 38 kHz signal can modulate any frequency/color of light, and an LED emitter can be modulated with a very wide variety of signals. Do you know which one you want to discuss first?



Joined Mar 24, 2008
A very good point. Turning an LED on / off is very basic digital electronics. It could be a LASER diode, or a transmitter, or ultrasonics, it doesn't matter what the device is.

When we talk about radio transmitters then frequency is important. When you talk about what is being modulated on the whatever the language changes significantly.