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I'm an electronics beginner.

Does an IR LED turn on like how regular LEDs turn on or does it only turn on when you've assigned a specific code for it to transmit?

The reason why I ask:

I bought some IR LEDs (940NM). I'm just trying to get them to turn on and view them with my phone camera. Do I have to use an IR sensor or can i just apply some sort of voltage and it turns on?

What is the easiest way of doing this? I'm using an Arduino.

Here is a link of the LED i bought:

https://www.amazon.ca/Gikfun-Infrared-Launch-Emission-Arduino/dp/B0154HHAKG/ref=sr_1_1_sspa?ie=UTF8&qid=1544379560&sr=8-1-spons&keywords=gikfun+ir+led&psc=1

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  • \$\begingroup\$ The IR LED itself turns on the same way as other LED's. But there are also IR LED transmit and receive modules which contain additional circuitry to encode and decode data. I think it might help if you edit your question to include more information about why you are asking this, and perhaps with an example part number that you are curious about. \$\endgroup\$ – mkeith Dec 9 '18 at 18:17
  • \$\begingroup\$ As Marcus said IR led is just as every other led but emitting light in wavelength which you can't see with bare eyes. IR led won't do anything fancy like control your television alone, for that it needs modulation of some sort.. \$\endgroup\$ – JuhoR Dec 9 '18 at 18:19
  • \$\begingroup\$ Those LED's should just turn on. You can try a 5V supply with a 1k resistor in series. Electrically, LED's are directional. Current can only flow through them in one direction. So if it doesn't work, try turning the LED around. Note that a lot of cameras have IR filters specifically to block IR light from getting to the sensor. \$\endgroup\$ – mkeith Dec 9 '18 at 18:29
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    \$\begingroup\$ The answer is in the Amazon comments... "Hooked them up, couldn't see the light so I flashed it on and off several times at my goldfish and they definitely reacted to it so I'd say they work quite well." You just need a calibrated goldfish if you want an accurate reading of the LED's efficiency. \$\endgroup\$ – Finbarr Dec 9 '18 at 19:17
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    \$\begingroup\$ Radio Shack used to sell a piece of paper (I have some here) that is coated with an anti-stokes phosphor that turns IR into visible light. No battery. No circuit. Just a piece of paper with phosphor on it. I'm sure someone sells such an item now, though I'm also sure it's not easy to find a source. Dirt cheap when Radio Shack was selling it. Look up IRI 1100, IRI 1400, and IRI 4400, for examples. The radio shack version looked like this, though of course it said "radio shack" on it. \$\endgroup\$ – jonk Dec 9 '18 at 21:17
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IR LED's themselves turn on the same way as other LED's. But there are also IR LED transmit and receive modules which contain additional circuitry to encode and decode data. Those LED's you linked to, however, appear to be simple LED's. They should just turn on. You can try a 5V supply with a 1k resistor in series. Electrically, LED's are directional. Current can only flow through them in one direction. The positive supply should be connected to the longer lead of the LED. But if in doubt, try it both ways just to be sure.

Note that a lot of cameras have IR filters specifically to block IR light from getting to the sensor, so the camera may not see it unless it is very bright. If 1k resistor does not show up, you can try a bit lower like 470 or even 330 Ohms. I probably would not go too much lower with a 5V supply for fear of damaging the LED. It may also be a good idea to try several different cameras if you can. Security cameras often do not have IR filters because they use IR light to provide something like night vision.

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  • \$\begingroup\$ If you have more than one IR LED, you may be able to use one as an emitter and one as a detector. Tape them together with black electrical tape (or other opaque tape) and then monitor the voltage on the detector while turning the emitter on and off. The goal is to prevent any ambient light from reaching the detector. Measuring current with an ammeter may work even better. Try both. \$\endgroup\$ – mkeith Dec 10 '18 at 16:32
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An IR LED is a "regular LED". It's a diode that emits light.

You hence use it like any other LED: You get a datasheet that says how much forward current they are typically used with (e.g. 10 mA), what the forward voltage is (e.g. 1.6 V), and then you put them in series with a series resistor to your voltage source. I'm not going to go into detail about series resistors here, because there's literally thousands of explanations and calculators for LED series resistors out there.

You might be confusing an IR LED with an actual IR transmitter integrated circuit, which contains an IR LED, but also other things like a digital packetizer, and a power supply.

But: if that's the case, we have no idea what IC you're talking about, so we couldn't answer that.

EDIT after you added a product page link:

This looks like LEDs. So, this is just a plain IR LED.

By the way, amazon's not the place to buy electronic components. You wouldn't buy car tires in a vegetable shop, either. Go for one of the large electronic distributors, like Arrow or Digikey. You'll notice that when you buy from professionals, components will come with datasheets that actually define what they do.

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Of course the IR led is turning on like a regular LED. Just test it with a camera or a phone to see the IR

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  • \$\begingroup\$ So do I wire it the same as i would with any other LED? I've edited my question to show which LED i'm reffering to. \$\endgroup\$ – Yousuf Dec 9 '18 at 18:21
  • \$\begingroup\$ You can turn on the IR LEDS like a normal LED. I don't understand why you bring IR sensor in this discussion. You use the IR sensor to read the data that you are sending with IR LED \$\endgroup\$ – pantarhei Dec 9 '18 at 18:25
  • \$\begingroup\$ Thanks for clarifying. Reason i mentioned sensor is because all my searches end up having the sensor as a requirement. I guess thats the most common test that people want to do. \$\endgroup\$ – Yousuf Dec 9 '18 at 18:27
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    \$\begingroup\$ You should explain your last sentence more fully. \$\endgroup\$ – Elliot Alderson Dec 9 '18 at 19:05

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