How do I send my own IR signal the with IR blaster? How do I send my own IR signal with the IR blaster?

I have a projector that came with an IR remote that doesn't have an app already. I want to program my galaxyS4 to control it. I have IR receivers that I can see the signal on via an arduino but I'm lost as to how to get to my phones own IR blaster.
This remote is widely accepted as being incredibly up to date, and compatible with hundreds of devices. It is not free, but there is a free version.
Something like this app lets you add codes for various devices.
In terms of programming, this would be off topic here, but since there might be alternatives you can use I've answered this. You could use the Android SDK and write an IR app yourself using the Andrid 4.4 APIs.

Infrared transmitters
When running on a device that includes an infrared (IR) transmitter, you can now transmit IR signals using the ConsumerIrManager APIs. To get an instance of ConsumerIrManager, call getSystemService() with CONSUMER_IR_SERVICE as the argument. You can then query the device's supported IR frequencies with getCarrierFrequencies() and transmit signals by passing your desired frequency and signal pattern with transmit().
You should always first check whether a device includes an IR transmitter by calling hasIrEmitter(), but if your app is compatible only with devices that do have one, you should include a &lt;uses-feature&gt; element in your manifest for &quot;android.hardware.consumerir&quot; (FEATURE_CONSUMER_IR).

(Note: I have zero involvement with any of the apps listed)