High power IR LED with short range

Hey guys!
I have this automation project and one of its features is to activate an AC and the TV via blynk app. It works good.
The issue starts with the IR LEDs and their range. Check my room’s draw. My main goal is to put the case with the NodeMCU and the IR LED at the 2nd power plug, so I can activate the lamps (relays) and the other things from there.
At first, I was using 3 common IR LED emitters, but since it’s “weak” and has short emitting angle, it could only activate the AC from the 2nd plug, not working with the TV. Note: with this setup, it has good range (can activate the TV from the AC wall), but has this limitation I told you above.

So I bought a high power, 3W, IR LED emitter. The thing is: for the AC, it works perfectly, i can point it anywhere in the room and I can activate the AC. But for the TV, it works worse than the common one, working only 2m (with the common one worked at the AC wall) away from the 1st plug.

By now I’m using the high power LED with the case at the 1st plug, it can activate both TV and AC, but i cant control the lamps because their cables are at the 2nd plug. The LED is driven by a 2N222 transistor with a 2.7 ohm series resistor. 5V power plug. Driving more than the recommended current, but since it’s only a small pulse, it’s ok.

I don’t think it is software related, but here is an example of sending an IR signal i use (38 kHz):

    Blynk.virtualWrite(V30, LOW);

The TV is a LG 32LN5400.

These are the IR LEDs:

Common one

High power - 3W 940nm

My room (wardrobe wall is like 6m long and AC wall 5m):

I’m working on a similar project to control audio-video equipment
and turn on TV+ Home cinema + Smart TV box with only one button :wink:

yeah i can do that too. the range and positioning to harmonize everything is the issue. from the current position, i can turn the tv and ac with one blynk button, voice and pc keyboard, but not the lamps.
If i put at the 2nd plug, i can activate the AC and lamps, but not the TV

First of all, this isn’t Blynk related and @Gunner is going to go ballistic when he reads this thread :rofl::rofl:

However, I’m a bit more indulgent, and happen to think that if people search for stuff like this and come across this site then it might result in another Blynk convert.
There are two main wavelengths used by IR devices - 850nm and 940nm. Your high power LED is 940, so as it’s working less well with the TV compared to the other LED, it’s probably a safe bet that the TV uses 850nm.
There may be other issues with the way the LEDs are working and it can sometimes be handy to use the camera of a phone or tablet to look at the output from the LED in a darkened room just to check that it’s doing what you want it to.

I’ve put together something similar and drive my LEDs directly off the pins of the NodeMCU, without any resistors etc. It works - at least for the time being!

My device is to control an AC and a ceiling fan. I chose to use two LEDs, connected to different pins of the NodeMCU (a Wemos D1 Mini in my case). I mounted everything in a small case and popped it on top of a speaker which sits on top of a bookshelf. That gives me good line of sight to the two devices and there’s an LED pointing directly at each one…

Using multiple LEDs of different wavelengths might be your answer, but you’re also likely to get better results if you can pick a high vantage point where you can get line of sight to all devices.


In the first setup, using 3 common LEDs, i used that thought. 3 different pointing directions at the 2nd plug. but it only worked for the AC from that position.
When i put the project next to the 1st plug, it works fine with both types of LEDs. Better range with the common one, and better angle with the high power.

How is that possible to the TV be 850 nm? Because the common LED is 940nm too and it works fine with the TV (with the right range and direction)

My main point is to put the project at the 2nd plug, so I can activate everything from there.

I know I can solve the problem arranging two NodeMCU, one at the 1st plug only with the IR leds and the 2nd at the 2nd plug for the relays and lamps, but that’s not optimized for me, financially and visually.

My biggest frustation is that i thought that the high power IR LED would solve any problem with range and intensity, as it did with the AC activation. I got the idea from this project:

It worked as intended with the AC, but with the TV is worse than the cheap IR LED, which worked 5m away from the tv but had bad angle.

Nah, I don’t actually have overt feelings one way or another.

Save me gunner as you have before

Try using 2 or more IR leds in series.
I had a similar problem and ended up using 3 IR leds to control TV, Aire conditioner and Music, and works great, almost 8meters away from the recievers. Point the leds in diferent angles, I think reflection have a lot to do.
Also, you can use the IR led without resistor, as you said, they are only short pulses.
Im using 3 leds in series powered with 12V and no series resistor.

But are you using the common ones? As for the high power it was expected to need only one. Well it’s worth a try.
As a mentioned i was using 3 common ones and they worked fine at the 1st plug but when I placed them on the 2nd only worked for the AC

The high power has a 140°emitting angle and is much more powerful than the normal ones. I thought it would work great for the TV as it does for the AC. I can point anywhere in the room and can activate the AC. In the video I linked, the guy uses the same and it works perfectly for both TV and Ac