Yalla!

helpfull and quiet, battery-saving and works silently in the background, Yalla app helps you let your friends know you're on your way.
Just open Yalla before you start your ride, choose the contact you want to notify, and you're good to go! the app will notify them via SMS as soon as you'll get near enough.
If you want, you can customify some stuff, like the SMS to be sent or the time to send it.

We chose to name our application after the word "Yalla" which means, in Hebrew, "prepare faster, I'm ready already!" so we thought it will be funny. Don't be mad at us, it was 3am in the morning and we were in the middle of a hackathon ;)