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

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.

Comments

[marshal56]

Hi alberto_canvas, I would like to control my TV with this big-eye-zaza(star war), I find the ir code from web, how can I make the ir code into audio? many thanks.

[Glenstr]

I'd like to build one of these, would these LED's work? http://www.ebay.ca/itm/5x-TSAL6400-Vishay-5mm-Infrared-LED-940nm-IR-Diode-Wii-/150659004375

thanks!

[tkkg]

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

[cgapeart]

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?

[AJMansfield]

220 ohms is nearer the mark for a current-limiting resistor in this application.

[ledartist]

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.

[AJMansfield]

The reason MP3 doesn't transmit as clearly is actually because MP3 is a LOSSY COMPRESSION, which filters out high-frequency, noise spikes, etc. Great for when you want to record audio. Horrible for recording a digital signal. Even using WAV is somewhat an abuse, since wave files generally have at least 16-bit depth, and therefore uses 16 times more space than should be needed to store the signal.

[humxa]

where to connect the ground wire?

[bisharam]

nowhere, just leave it free.

[alaskanbychoice]

The ground wires are tied together and insulated. The two power wires go to the LEDs and are hooked up opposite of each other. DSLRBOT explains it all.

[khurtwilliams]

Thanks a lot. I modified the design somewhat. I used a Radio Shack 3.5 mm mini stereo plug (Part # 274-0869) and soldered the LED directly to that to make the result more compact.

[g3lrod]

What LED did you use?

[pulcinella]

To me it does not work with iPhone 4S firmware version 6.0 where am I wrong? maybe I got the wrong LED?

[g3lrod]

The firmware version shouldn't make a difference, all it is doing is pulling current from the audio jack when music is playing. I would check to make sure you didn't make any silly mistakes (not twisting the ground wires, hooking up the LEDs correctly, etc.) first.

[iroamz]

Hi All,

Tried this with a Canon 400D DSLR and it worked, a bit weak but it worked close range...I used the purple colored LEDs (I think they are 950nm).

[humxa]

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?

[jamesmangold]

Can this be applied to make a photo-gate timer for physics lab activities?

[dcyane]

I love this app! But why not surport DVs? I need it to control the record status of SONY DV, please add DV functions to it, Thanks! [e-mail]

[khurtwilliams]

The app serves a specific purposes. Remotely triggered a DSLR camera from an iPhone/iPod Touch. The app is written with that specific use case.

[fbooms]

Hello,
i have done all the Things you shown but it dont work. I have a Canon 600D. What is wrong??? You say that sometimes problems in Europe. Why??? What ca i do?

[khurtwilliams]

List of camera supported here: http://www.dslrbot.com/specifications/

[andrew121007]

Is it possible to maybe add a battery to amplify the led power? I've got a pretty big amplifier on my computer that if put on maximum will show the led light up (through camera) but on phone it doesn't light up. I can't test my computer because I don't have any ir devices near it. But when I try with my phone it does not function. I've constructed it how it should.

[khurtwilliams]

Read the title of the post. This is designed specifically for triggering a Nikon DLSR from an iPhone.

[andrew121007]

Ok so if I put it close enough to the TV and move it around, it functions, so that means it definitely needs amplification.

[santakrooz]

Hi just built this, but the IR LEDs are emitting white light (and it's not working with my Nikon) - I ordered 940nm but I'm now suspecting that they sent 850nm instead. Can someone confirm that the 940nm IRs should not be emitting any light? thanks

[nodoubtman]

what is the use of this?

thanks!

[deandaman]

its used to remotely trigger function from your DSLR camera which is quite handy.

[dmclaughlin1]

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.

[nodoubtman]

what is this used for ?

thanks!

[abana]

Ok, so i've made the transmitter but it has a really poor range, like maybe 2ft max.

Is the length of the cord a matter?

Also, what is it that you guys said about a resistor? how many ohms?

[msouza]

BTW, thanks a LOT to Share this. I will test it today ! :)

[msouza]

What about the LEARN scheme ? Do you have it ? And do you have any clue to make an workflow to Record and reproduce the "commands". Just link buttons to Mp3 files and play them ? :)

[squarefrog]

Pretty good - but perhaps a more flexible option would be to simply solder a couple of IR LEDs to a 3.5mm jack, and then use a standard 3.5mm stereo extension cable for length.

[zmohiuddin]

Would a 950nm diode work? Those are the only ones they had at Radiocrap.

[Mdob]

That should work just fine.

[crtn2]

i dont think this will work. you should twist L and R wires together and connect ledt between them and ground wires

[cgapeart]

I would have to see what the signals look like to know for sure, but I think the point here is that you can create a larger voltage difference by driving one of the sides positive, and the other negative with respect to ground. Having two LED's going opposite to each other means you can generate voltage in both directions of that.

[crtn2]

you're right, but the right channel should be inverse of left channel or this wont work.

[piesforyou]

Hi alberto_canvas, I thought this was a great guide and it gave me an idea for using it as a DSLR intervalometer. You can find details of how I used it here:

http://www.pentaxforums.com/forums/pentax-dslr-discussion/131633-absurdly-simple-diy-k-x-remote-timer-using-mp3-player.html#post1368821

[alberto_canvas]

Hi piesforyou, ive actually developed an app for the iPhone quite a while back for the same purpose. Made for canon users, but have been developing it for use with other cameras.

http://www.dslrbot.com