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 ..
The right channel will produce the in-between signals for the off time ..
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

Step 1: 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.

<p>Hi <br>Could someone please explain why 2 LEDs are needed? <br>Wouldn't it work with just 1 LED? All my TV remotes only have 1... <br>thanks</p>
<p>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.</p>
<p>I would also be curious as to the logic behind using two LEDs.</p><p>Couldn't you just as easily use two regular diodes between the left and right signal with the positive of the LED connected in between them? Then the LED negative would go to ground, and we only used 1 LED. this circuit also doesn't leave any floating grounds. The only concern I would have about this would be the LED possibly discharging the circuit too soon?. The main benefit of the diodes which I could see in this version would be that the LED will not flash until a voltage threshold is reached. Also there will be no possibility for current to drop negative on the LED cathode (+) due to differentials between the channels. Instead it will only drop negative when there is no &quot;ON&quot; (also it will drop negative just after the &quot;ON&quot; signal and it will stay there until the next &quot;ON&quot;).</p><p>Even without the diodes, if you combine the left and right signals you will still end up with effectively twice the sample rate (compared with a mono signal) because each channel can carry on or off signals. So if the signals are combined then either channel can carry the &quot;ON&quot; signal and the net effect would be the LED flashing. In this case the negative voltage drop on both channels would be because of the one way current flow nature of diodes (even ones which emit light), there would be no protection from differential signals in this circuit. I don't see why this wouldn't work, too, so long as the software is designed around a mono signal.</p><p>If it's really about setting up some sort of frequency cascade, or something else, I would like to see some evidence or something. Somebody set me straight with a link! :-) If it is about some sort of cascade, then couldn't one of the LEDs be replaced with a regular diode? This would still allow the signal to move forward at all times until the frequency is enough to discharge the LED. </p><p>cheers!</p>
<p>I read the patent and I'm pretty sure I follow the logic. I still don't understand why this is necessary. </p><p>Is it because the pulses of an IR remote are so fast that a single on-off signal cannot be generated fast enough via an audio signal? They don't look so fast (the blink patterns). It seems like you should be able to accomplish this with 1 audio channel (or dual mono, L &amp; R, combined back into 1 channel). Provided that when the audio tone pulses the voltage rises high enough(and fast enough) for the LED to emit. Also the voltage must drop quickly enough that the light is out long enough to actually pulse. I think it would be much easier to just use a pwm output (although that is probably defeating the whole purpose :-)</p>
<p>There are some good images in the patent pdf:</p><p><a href="http://www.freepatentsonline.com/6931231.pdf" rel="nofollow">http://www.freepatentsonline.com/6931231.pdf</a></p>
<p>why can't you use one ir led instead of 2?</p>
Trying this on iPhone 4s, iPod 4, iPad mini without success :(<br><br>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.<br><br>What am i missing?
<p>they are not any normal LEDs</p><p>They are called infrared LEDs and have a different job.</p>
<p>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?</p>
<p>I think this is patented. https://www.google.com/patents/US6931231</p>
A patent for this would never hold.
<p>Hi all,</p><p>I need a little help. I've built the transmitter using two diodes (specs attached image) and have a Pentax K-R camera. I've soldered all of the connections, no shorts, good solders, and I've double checked the reversal of the diodes. I've tried multiple apps on multiple devices, including IrdslrRemote and Cam Control on my iPhone 6, and DSLR Remote from 2 different droid tablets. I have the volume at maximum. I also have a regular remote for my Pentax that works fine, so I know the camera's IR receiver works.</p><p>I'm not having any success, unfortunately. I need some advice on how to troubleshoot my transmitter. Does someone have the ohm meter values I should expect at different test points? Or some other clever way to find the fault in my transmitter?</p><p>Thanks,</p><p>Luke</p>
<p>OK, partial succes. </p><p>First, electrically, all is well. Connections all test 0 ohms and resistance measured across the diode is matched at the headphone jack connector, so the wire is good.</p><p>Using Cam Control on my iPhone 6, I can trigger the shutter on my K-R, but not reliably. It seems that the angle is important and very sensitive. Should this be expected? How far away should the diodes be from the receiver on the camera? The specs for the diodes say the viewing angle is 45 degrees. In what direction? I'm expecting I should point the tip of the led dome at the sensor on the camera, but my results with that are inconsistent.</p><p>Tips?</p><p>Thanks.</p>
<p>Found the PhotoBooth tip to verify my transmitter works well. Purchased the app. Still had the same issue with intermittently triggering the camera. Turns out this camera has a strange viewing range for the remote. Does not work well at all when the remote is pointed at the sensor from in front of it. Put the transmitter to the side, above, or below the sensor, at a fairly harsh angle, and it works very well.</p><p>This is fine as I want to strap to the camera when using it so I'll just strap it to the side or top, right across the shutter button.</p>
<p>BTW, I'll buy the dslr.bot app as soon as I'm sure I've built this thing correctly. :) Just didn't want to spend the money until I knew I'd be able to use it.</p>
<p>I found the patent for this build:</p><p><a href="http://www.freepatentsonline.com/6931231.html" rel="nofollow">http://www.freepatentsonline.com/6931231.html</a></p>
<p>You should be able to make the exact same device buth with two IR <br>receiver diodes plugged into the microphone jack of your computer, <br>right? <br> Or is one enough and only for one channel using channel and ground <br>instead? I was curious if you could record a signal and use it straight <br>away.<br>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. </p><p><a href="https://i0.wp.com/www.planetmobile.it/jumpjack/remote-dvd-lg-rh255-PLAY-wav-76000Hz.JPG" rel="nofollow">https://i0.wp.com/www.planetmobile.it/jumpjack/rem...</a></p>
<p>It would be interesting to know more than &quot;infrared LEDs 940nm 2x&quot;, 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? <br>There are several things to choose from when buying the IR LED.<br>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.<br>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. <br>3. Current? There's 20-180mA in the selection I'm looking at, I assume it should be low rather than high? <br>4. Radiation effect mW/sr, usually goes hand in hand with angle and current. <br>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. <br><br>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). <br>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. <br>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.<br>Going to make a small one for the phone... <br>Thanks!</p>
any idea of how to change that so that it works with red/green or blue LED?
<p>If you just want to flash the LED you can do the same, not that it will work as IR remote.</p>
<p>The receivers on devices can only see IR beams, so you're out of luck.</p><p>But maybe the light from a very bright white led has some IR components which can trigger the receiver...</p>
2 LED MUST ...
<p>Hi , Anybody try with ir droid ??<br>Thanks</p>
<p>This is great. Thanks mate</p>
can this be used to trigger an ON/OFF switch?
<p>Yes, as long as you know/record the IR signal needed to turnoff the device.</p><p>You can use THIS device itself to record the signal from an existing remote:</p><p>http://jumpjack.wordpress.com/2008/05/20/worlds-cheapest-remote-control-replicator-just-1/</p>
<p>Also would these be ok?</p><p><a href="http://www.ebay.co.uk/itm/5mm-IR-LED-Pair-Infrared-TX-RX-transmitter-receiver-Diode-x-2-Pair-/291110141103?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item43c7843caf" rel="nofollow">http://www.ebay.co.uk/itm/5mm-IR-LED-Pair-Infrared...</a></p><p>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.</p>
<p>@jumpjack2</p><p>Could this record any IR signal? I want to control a couple of those colour changing bulbs... then disco time xD</p><p>If it can't update them that rapidly, don't worry. Just is it possible?</p><p>Other stuff I'm thinking of:</p><p>- Turning on when I'm near to my computer through bluetooth and my phone</p><p>- Changing colour depending on what part of the room I'm in, with some motion sensor... idk</p><p>- Gradually waking me up in the morning</p>
<p>Hi!</p><p>Can you tell me will this work with the normal shutter cable converted (attached photo) to 3.5mm connector connected to iPhone/iPad?</p><p>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? </p><p>Like this one: </p><p><a href="http://i1144.photobucket.com/albums/o498/huananphoto/1yue19hao/CX744_5.jpg" rel="nofollow">http://i1144.photobucket.com/albums/o498/huananpho...</a></p><p>Thanks! ;)</p>
<p>And this is how I did it :D</p><p><a href="http://vedranpapes.from.hr/essays/2014/07/dslrbot-cam-control-with-ir-remote-from-ir-headphones-philips-sbc-hc202/#more" rel="nofollow">http://vedranpapes.from.hr/essays/2014/07/dslrbot-...</a></p><p>Using an old Philips IR transmitter :D</p>
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.<br><br>Can I just play back the mp3 and get the desired result? If so, <br>What should the audio file sample rate and bit depth settings be? <br>Do there need to be any resistors, capacitors, external power added to the LEDs?<br><br>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.
<p>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.</p><p>Resistors are not needed.</p><p>External power could be useful to amplify the signal... but we'd need an amplifier schematic...</p>
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?
<p>You need to record signals from your remote:</p><p>http://jumpjack.wordpress.com/2008/05/22/remote-control-2/</p>
Hi alberto_canvas, how's that other tutorial (capturing and sampling IR code) coming along? <br><br>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
<p>Please look here for recording: <a href="http://jumpjack.wordpress.com/2008/05/22/remote-control-2/" rel="nofollow">http://jumpjack.wordpress.com/2008/05/22/remote-co...</a></p><p>The resistor could protect led from too high currents but it will also reduce range.</p><p>And I don't think the resistor is actully needed, as the led stays on just a few seconds and even not continuously.</p>
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.<br><br>Take the resister out of that diagram, and you have exactly what this instructable is detailing.<br><br>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.<br><br>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?<br><br>
220 ohms is nearer the mark for a current-limiting resistor in this application.
Assuming that iPhone output of&nbsp;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.<br> Of course 3.5V is plenty for IR (or even white) LEDs.<br> <br>
what is the use of this? <br> <br>thank you! <br>marC:)
<p>Replacing broken remote controls.</p><p>Pranking people by turning on/off secretely their devices. :-)</p>
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???
<p>Look at my page, I wrote a couple of programs for windows, or you can just create the needed wav files by hand.</p><p>http://jumpjack.wordpress.com/2008/05/20/worlds-cheapest-remote-control-replicator-just-1/</p>
<p>I don't really understand. You say that the two channels will respectively play:</p><p>0101010101<br>1010101010</p><p>Since the IR receiver can't tell which LED is sending the data, the receiver will simply see:</p><p>1111111111</p><p>I.e., in this example there will always be one LED on. What am I missing?</p>
<p>Leds will be on only if there is &quot;sound&quot; playing, when it is quiet both leds will be off. Looks like 2 leds needed to produce &quot;1&quot; signal for a long time, otherwise there will be 16KHz blinking of one led.</p>
one thing i dont understand, i have iphone 5 with ios 7 and i have dslr bot <br>do i need to play some music in backgrount for use shot and ir transmitter? <br> <br>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 <br> <br>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. <br> <br>The third ring is usually used to carry extra input like microphones or headphone mounted volume buttons etc
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). <br> <br>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. <br> <br> <br>
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... <br> <br>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?
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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