It may not be very large in some cases. On the lg g3, for example, the ir blaster is about the size of the tip of a pen.
[header] How to use an android ir blaster [title] Check if your phone has an ir blaster. [step] Many phones do not come with an ir blaster. To know if your phone has one, check your device and look for a glossy black piece of plastic on the top somewhere.