Reccomended probe for depth, temp, speed

[Grizzly8]

What's the best probe for keeping my set up simple? 
 

I don't want to mount a fish hawk or another display, would rather use an app on my phone. Is it possible to run a probe on a downrigger sending the data straight to your phone? Is there a way to hook it up to a Garmin that I already use? 
 

I've seen smart troll, fish hawk, and Scotty seeker. What are people recommending? For frame of reference this is for a 17 foot personal use boat.