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Picture of DIY Infrared transmitter for iPhone, iPod
Create a Infrared transmitter for any portable mp3 device, ie phones, music players etc.
This tutorial is for creating the Infrared transmitter only.

Can be used with iPhone App DSLR.BOT. http://dslrbot.com 
Used for controlling Canon EOS, Nikon, Penta and Sony Cameras.

The way this transmitter works is it sends infrared on and off signals from the audio playback coming from your headphone jack. Having saved an audio file with the correct on and off timings, you can play back this audio track through your portable music player and trigger infrared devices.

This transmitter works better with a WAV audio playback, however this has been successfully tested as an MP3 audio track.  The WAV track generally produces  a clearer signal as they can playback a 38 KHz modulation (Infrared frequency rate), by dividing the frequency between the two stereo channels. 19 KHz for the left channel and an inverse 19KHz signal for the right.

To better illustrate this the left channel will play an on and off signal ..
0101010101
The right channel will produce the in-between signals for the off time ..
1010101010
Therefor each channel will take turns producing a infrared signal creating a higher frequency rate, equal to that of an infrared remote control.

The Items needed for this DIY project are ..
1) Infrared LEDs 940 nm 2x
2) 3.5 mm stereo headphone minijack

 
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Step 1: Prepare the headphone jack

Picture of Prepare the headphone jack
The first thing to do is strip the wire ends then twist the ground wires together. The ground wire is usually the wire unprotected by a coloured casing.

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Mouro_811 month ago

Hi
Could someone please explain why 2 LEDs are needed?
Wouldn't it work with just 1 LED? All my TV remotes only have 1...
thanks

e5frog Mouro_8111 days ago

I read somewhere that you'll double the frequency range by using both channels and reverse one. You'll basically double the amount of peaks from your transmitter.

e5frog e5frog11 days ago

There are some good images in the patent pdf:

http://www.freepatentsonline.com/6931231.pdf

e5frog11 days ago

I found the patent for this build:

http://www.freepatentsonline.com/6931231.html

Blitzblank1 year ago
Trying this on iPhone 4s, iPod 4, iPad mini without success :(

Have 925nm and 870nm LEDs with 1,35V and 100mA each, both do not work. Tried this with green LEDs (visible light): not working either.

What am i missing?

940nm seems common for IR receivers, you need to match it what what you want to control. I'd try some 20mA or 50mA LEDs. Have you hooked it up correctly using right and left channel and not ground? What sound file are you playing back?

e5frog11 days ago

You should be able to make the exact same device buth with two IR
receiver diodes plugged into the microphone jack of your computer,
right?
Or is one enough and only for one channel using channel and ground
instead? I was curious if you could record a signal and use it straight
away.
As can be seen in this picture where one LED receiver was used you can easily pick up more interference with a long cable, I'm guessing that's the reason for the long wave pattern and the reason for not having signals on straight line.

https://i0.wp.com/www.planetmobile.it/jumpjack/rem...

e5frog11 days ago

It would be interesting to know more than "infrared LEDs 940nm 2x", is 940nm the interesting peak for most IR receiving equipment? What voltage can I expect to get from the sound out put, what current can I expect with no resistor added?
There are several things to choose from when buying the IR LED.
1. Peak wavelength, 880 and 940 seems common when buying IR LEDs, if it's a LED with broad range it may not matter as much.
2. Angle - perhaps less important, if you aim well and want as much light as possible in the direction you're pointing a low angle should be preferred.
3. Current? There's 20-180mA in the selection I'm looking at, I assume it should be low rather than high?
4. Radiation effect mW/sr, usually goes hand in hand with angle and current.
5. Forward Voltage, there's 1.2 to 4V I assume if it's too high the LED won't turn on at all. What's the expected maximum from an ordinary phone headphone output? Where's the limit where we can't expect it to work - in general.

I don't see any of that data here and no article number or place where you bought yours. I read somewhere else that a 2V peak-to-peak is expected from a headphone output - that's with a normal impedance load though without that load we will get more. With the diodes hooked between Right and Left output you'll have the entire voltage range available for each diode (when right is max and left is min or vice versa).
If I'm just taking IR leds from old remotes or other IR transmitter (headphones f.e.) then it may not matter, if I'm buying new parts then these things would be nice to know, at least the specifications of what was used and working.
Did you mention that you can check with a digital camera to check that you have output? It will show as bright purple flashes on most camera screens.
Going to make a small one for the phone...
Thanks!

nenisea1 year ago
any idea of how to change that so that it works with red/green or blue LED?
e5frog nenisea11 days ago

If you just want to flash the LED you can do the same, not that it will work as IR remote.

jumpjack2 nenisea9 months ago

The receivers on devices can only see IR beams, so you're out of luck.

But maybe the light from a very bright white led has some IR components which can trigger the receiver...

Jeetu66001 month ago
2 LED MUST ...
kotor712 months ago

Hi , Anybody try with ir droid ??
Thanks

davidbarcomb4 months ago

This is great. Thanks mate

can this be used to trigger an ON/OFF switch?

Yes, as long as you know/record the IR signal needed to turnoff the device.

You can use THIS device itself to record the signal from an existing remote:

http://jumpjack.wordpress.com/2008/05/20/worlds-cheapest-remote-control-replicator-just-1/

Also would these be ok?

http://www.ebay.co.uk/itm/5mm-IR-LED-Pair-Infrared...

And would you need to use the receiver ones to record, then swap them back to send. I don't need to do both at the same time, I'll record everything first.

@jumpjack2

Could this record any IR signal? I want to control a couple of those colour changing bulbs... then disco time xD

If it can't update them that rapidly, don't worry. Just is it possible?

Other stuff I'm thinking of:

- Turning on when I'm near to my computer through bluetooth and my phone

- Changing colour depending on what part of the room I'm in, with some motion sensor... idk

- Gradually waking me up in the morning

vedranius8 months ago

Hi!

Can you tell me will this work with the normal shutter cable converted (attached photo) to 3.5mm connector connected to iPhone/iPad?

As I have a cable from battery grip which is on one side a Nikon's connector and on the other a 2.5mm plug. What if I get a adapter from 2.5mm to 3.5mm?

Like this one:

http://i1144.photobucket.com/albums/o498/huananpho...

Thanks! ;)

nikond3200_batteryGripCable.JPG
vedranius8 months ago

And this is how I did it :D

http://vedranpapes.from.hr/essays/2014/07/dslrbot-...

Using an old Philips IR transmitter :D

DSC_8076.jpg
I was wondering as well about the possibility of using mp3 files as a source as well. I've got a working IR receiver input into the sound card on my computer. I get good signal on an oscilloscope, and can see that same waveform in an audio processing app (I use soundforge). I'm trying to build the transmitter now.

Can I just play back the mp3 and get the desired result? If so,
What should the audio file sample rate and bit depth settings be?
Do there need to be any resistors, capacitors, external power added to the LEDs?

I've testing the transmitting LEDs and I can see the signal on a camera but when aimed right at the tv, nothing happens. Any thoughts? Many thanks.

MP3 files can't do the job as they use lossless compression, which means they completely change a high frequency signal (38 kHz) like this.

Resistors are not needed.

External power could be useful to amplify the signal... but we'd need an amplifier schematic...

humxa2 years ago
I've built this and works great but can any buddy tell me any other app that uses this to trigger Television sets, blue ray players and such?
jumpjack2 humxa9 months ago

You need to record signals from your remote:

http://jumpjack.wordpress.com/2008/05/22/remote-control-2/

tkkg4 years ago
Hi alberto_canvas, how's that other tutorial (capturing and sampling IR code) coming along?

Also, I've seen the same setup elsewhere on the web with a minor difference, there's a 10ohm resistor added. Is that necessary? Here's the source http://img212.imageshack.us/img212/8740/icouch2mg1.png
jumpjack2 tkkg9 months ago

Please look here for recording: http://jumpjack.wordpress.com/2008/05/22/remote-co...

The resistor could protect led from too high currents but it will also reduce range.

And I don't think the resistor is actully needed, as the led stays on just a few seconds and even not continuously.

cgapeart tkkg4 years ago
On the plus side, it's going to limit the amount of current drawn by the diodes, which is probably safer for your audio player. On the minus side, the IR output won't be as bright.

Take the resister out of that diagram, and you have exactly what this instructable is detailing.

A typical infrared diode has a drop of 1.3 volts across it. Based on what I can find, the iPhone should be able to run up to 3.5volts peak to peak -- depending on the audio signal, that means it could do up to 7 volts -- and the internal resistance of the wires and diode will have to take up the slack from the 1.3 volt drop. i.e. 7-1.3 = 5.7 volts to drop.

I don't know if 10 ohms is the right value, and I don't know what kind of current limiting capabilities are built into the iPhone audio output, but I would think that some kind of resistor would be a good idea to protect the audio output of the phone. Any thoughts?

220 ohms is nearer the mark for a current-limiting resistor in this application.
Assuming that iPhone output of 3.5 V peak to peak is correct (I think it is), you can still only get 3.5 V max between the LR channels, as opposed to 1.75 V between one of the channels and the GND.
Of course 3.5V is plenty for IR (or even white) LEDs.

nodoubtman1 year ago
what is the use of this?

thank you!
marC:)

Replacing broken remote controls.

Pranking people by turning on/off secretely their devices. :-)

osiris121 year ago
hello. I got the IR to work but what software do I use to generate audio IR codes. I have hex codes for my TV, but how do I encode them into audio???

Look at my page, I wrote a couple of programs for windows, or you can just create the needed wav files by hand.

http://jumpjack.wordpress.com/2008/05/20/worlds-cheapest-remote-control-replicator-just-1/

arpruss10 months ago

I don't really understand. You say that the two channels will respectively play:

0101010101
1010101010

Since the IR receiver can't tell which LED is sending the data, the receiver will simply see:

1111111111

I.e., in this example there will always be one LED on. What am I missing?

japuser arpruss10 months ago

Leds will be on only if there is "sound" playing, when it is quiet both leds will be off. Looks like 2 leds needed to produce "1" signal for a long time, otherwise there will be 16KHz blinking of one led.

zokizo1 year ago
one thing i dont understand, i have iphone 5 with ios 7 and i have dslr bot
do i need to play some music in backgrount for use shot and ir transmitter?

and yes, does this work for iphone5 becouse headphone jack its different he have 3 black marks, and this one on picture have only 2

thanks on help :)
with the 3 channel plugs you can solder the wires connected to the the innermost bands together to emulate a simpler 2 channel plug.

The third ring is usually used to carry extra input like microphones or headphone mounted volume buttons etc
snoop9111 year ago
I'd like to use my android to control my tv directly via IR. Would this hardware work for that? (Assuming I create my own 38k carrier frequency wave file in Audacity that has the right pattern).

If so, does this work in the same fashion as all those commercially available ir emitters? I've never opened one up, but they usually have a 3.5mm plug on one end that goes to a pc, with the other end having one or two ir blasters. The blasters are usually very small, so I wouldn't think there's 2 leds back-to-back.


ta2dwez1 year ago
i am trying this instructable at the moment but im not getting any output from the LED. I m using this to hack my TV using a .wav file to access a secret service menu, anyways...

i have tested the remote LED and also tried 2 audio cables. im testing if it is functioning by looking through a camera and checking if the LED lights up but no joy. Any ideas on what could be the problem?
pinzon1 year ago
Thank you. I was worried about how to use my Nikon D70 to practice time-lapse and solved! and free. It works fine.
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