Based on your description, you might want to look into a Blutooth reader. You can get them off of e-bay cheap. Be somewhat cautios though... don't buy the chepaest deal you find...
Anyhow... Android and Iphone both have apps that interface with these BT readers. There are several to choose from and you'll need to look through the ratings and descriptions and figure out which app has the features that you like the best.
The one I ended up getting has a TON of instant data that I can look at while driving but even more important to me, was the app that gave me the ability to data log. I have a 64G data card in my phone. I'll tell ya... that's a LOT of FN data logging. LOL
Check it out and see if something like that will suit your needs. If not, there are certainly other possibilities out there for readers.