audio.html

<p class="lead">
    Transmitting IR signals via the 3.5mm audio jack (irplus WAVE)
</p>
<p>
        <a href="https://play.google.com/store/apps/details?id=net.binarymode.android.irpluswave" target="_blank" class="btn btn-primary">Install</a>
    </p>

<p>It is possible to IR signals via the audio port. It does this by modulating the data onto a sine which is half the carrier
    frequency (38 kHz is the default if the remote doesn't have a frequency specified). After rectification the sine becomes
    a full frequency carrier. The wave is inverted on the right channel, so the left and right channels can be used to double
    the voltage.</p>

<p>
    Source:
    <a href="http://www.lirc.org/html/audio.html" target="_blank">http://www.lirc.org/html/audio.html</a>
</p>

<p class="lead">
    Build the IR blaster
</p>

<p>Depending on the voltage power of your phone you might need to build an active (with battery) or passive IR blaster. I recommend
    to get IR-LEDs with the lowest Uf voltage possible and test with an 1.2V power source (e.g. 1.2V rechargable battery)
    if they are bright enough.
</p>
<p>Warning: Please try to check the wiring multiple times before attaching this to a smartphone. Shorting and/or overloading
    may damage the phone's audio jack. Also I'm not responsible for any damaged caused by using this method. Try at your
    own risk. I have tested with a passive blaster with a very simple circuit. 2 IR-LEDs connected with each other. The diagram
    is an adapted version of the lirc.org diagram with the resistance removed. </p>

<img src="images/audio_transmitter.png" class="img-fluid" alt="Responsive image">

<p>This is a photo of my solution using a 'B-Speech Rx2' Bluetooth Stereo receiver. I can position this device with the self-made
    blaster connected near the devices i want to control and be able to send IR commands even without direct line of sight
    from the phone. Actually this is even better than using the integrated IR-blaster! </p>
<p>Note: This can work with almost any Stereo A2DP Bluetooth Stereo receiver, but it needs to have a high voltage / peak out.
</p>

<img src="images/audio_a2dp.png" class="img-fluid" alt="Responsive image">

<p class="lead">
    How to use irplus WAVE
</p>

<p>
    I have ported this method to Android so you can use the Audio-Port or a Bluetooth A2DP Stereo receiver (Mono will probably
    not work due to low voltage) to send IR-codes on any phone. To use this feature make sure to download irplusWAVE from
    the PlayStore as this is a separate app specifically for this use and make sure the Volume rocker for Media is at 100%.
    If you want to use Bluetooth/A2DP make sure you are connected to the stereo receiver via android (pairing already done)
</p>

<p class="lead">
        YouTube Tutorial to build IR blaster
    </p>
    
<p>
        Made by <a href="https://www.youtube.com/channel/UCNSfV3L4jv7Kx22lxo0Sv-g" target="_blank">Cameron Gray</a>. Thanks!
    </p>
    
    <div class="embed-responsive embed-responsive-16by9">
            <iframe class="embed-responsive-item" src="https://www.youtube.com/embed/cD2c2DhlvuQ?autoplay=0" allowfullscreen></iframe>
        </div>