A directional smartphone mic that is easy to carry and setup. This comprehensive video tests just how good this mic is under a variety of conditions. On the test bench, outdoors- with and without the windscreen and whether it is value for money.
RODE VideoMic Me: http://www.rode.com/microphones/videomicme
If your mobile phone camera is close to the microphone input you would be better considering the items below:
RODE VideoMicro: http://www.amazon.com/gp/product/B015R0IQGW/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B015R0IQGW&linkCode=as2&tag=simaudtip06a-20&linkId=ZPGZ3Y4QSUB3IAUM
Smartphone Holder: http://www.amazon.com/gp/product/B00CR74FKA/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00CR74FKA&linkCode=as2&tag=simaudtip06a-20&linkId=NR63T3R2AJ7KF6I2
RODE SC7 adapter cable: http://www.amazon.com/gp/product/B00L6C8T22/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00L6C8T22&linkCode=as2&tag=simaudtip06a-20&linkId=EV6GAW5JHUYFNDSD
Thread adapter to connect the smartphone holder to the VideoMicro: http://www.amazon.com/gp/product/B006N5B9BK/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B006N5B9BK&linkCode=as2&tag=simaudtip06a-20&linkId=4OATNC5ZUPTEMWTB