# using an arduino pro mini to control a high powered infrared led to control TVs

Hi, I'm a pretty big noob on circuit design, I'm good at math though and I am familiar with both AC and DC equations. My project is to use an arduino pro mini to control a high powered infrared led to control TVs. The reason I am using a high powered LED is because I don't want the led to have to point directly at the tv as its going to be in a fixed location, and I also kind of want the additional experience of working with a higher powered LED as I think a regular LED is just too simple. So I'm using a 940nm LED 5W 1.3v-1.5v forward current of 1500mA and a max current of 3000mA. I'm thinking of putting 2000mA-2500mA through as it certainly will not be on constantly except for when holding volume up and down. So i wanted to use a single power supply to power the arduino and LED, what is my best choice? I've been leading toward using a switching mosfet. I already have a 12v 3A power supply, was wondering how to split it to both the arduino and the transistor (i have also read some articles relating to transistor such as Transistor Switching Circuit Design and Its Theory Transistor Switching Circuit Design and Its Theory). Do I need a voltage regulator board too? And a more general question, can you control both voltage and current with a voltage regulator? ignorant huh? Current must reduce after passing through the mosfet, as it is not always passing current. So how do I separate this voltage current ratio in general? Thanks a million!

And a more general question, can you control both voltage and current with a voltage regulator?

No, unless you have some magical way of controlling your load impedance.

Current must reduce after passing through the mosfet,

No?

as it is not always passing current

If it does not pass current the there is no voltage either.

So I'm using a 940nm LED 5W 1.3v-1.5v forward current of 1500mA and a max current of 3000mA. I'm thinking of putting 2000mA-2500mA through as it

In which case you will need a constant current supply which is controllable from an Arduino. As it is for a remote controller then they use modulated IR light so you have to arrange for modulation as well as the encoded data.
However:-

The reason I am using a high powered LED is because I don't want the led to have to point directly at the tv as its going to be in a fixed location,

Every LED has a radiation pattern and no matter how powerful it is their are some directions where the light does not emit at all no matter how powerful the LED is. There are designs of LED that give you a 360 degree emission but not a spherical emission pattern. Like this one:-

The power doesen't jibe. A 1.5V V(f) @ even 2500mA I(f) is only 3.75W. That might be good though. I don't know if I would want to be looking in a 5W led and not know it was on.

Sorry for my lack of ability to communicate, great job understanding my nonsense. I'm not even sure what I meant about the mosfet, probably was hoping I could make a buck converter without lots of support circuitry, which is just silly haha. Thanks for the info about the LED.

Unless you have a very large indoor arena, I would stick with running 300-500mA thru the IR LED. Then I would put 2 or 3 LEDs in series and if you really needed more I would just create copies of the above. (If you are going for more IR power, please check out the relevant health guidelines)

Then I would mix the IR LEDs being used with different 'angles'. e.g TSAL6100, TSAL6200, TSAL6400. That should give you a very effective solution in 99% of domestic situations. (IR wll reflect off walls and fixtures...just like any light source.

See: https://www.analysir.com/blog/2013/11/22/constant-current-infrared-led-circuit/
for an example circuit.

Using this and IRremote on an Aduino should be fine, as long as you ensure your power supply is capable of the extra current draw. If you test with 1 x TSAL6100 & 1x TSAL6200 @100->300 mA you may be pleasantly surprised. (If not add 2 more until you are satisfied)

I wonder if you are not working on the wrong end of the IR problem. Our Samsung manual is quite specific relating to the cone of view of the IR receiver. It is rather narrow and the remote needs to be pointed quite close to the sensor on the TV.

Paul

Paul_KD7HB:
I wonder if you are not working on the wrong end of the IR problem. Our Samsung manual is quite specific relating to the cone of view of the IR receiver. It is rather narrow and the remote needs to be pointed quite close to the sensor on the TV.

Soooo true, and a bloody hassle.

In the eighties, IR remotes had a 9volt battery and four wide angle IR LEDs in series.
You could control a TV from 12meters away without accurately pointing the remote at the receiver.
The reciever was positioned high in the front panel. Not blocked by tables and arm rest of chairs.
With my Samsung TV (at ~4meters distance) I have to pick up the remote and point it with a stretched arm at the receiver.
A remote with a round bottom makes things worse. You HAVE to pick it up to push a button. Grrrr.
Leo…