Simple phone app / speed sensor?

joebristol Posts: 327
I've looked though the other topics and can't quite see what I'm after.

Innately mountain bike for fun / social, with some occasional road biking g with a group of lads as well. I've had a shoulder operator to stabilise it (5 weeks ago) and so have acquired a basic turbo to try and keep my legs going a bit until I get the go ahead from the physio to ride a bike outside.

Turbo is a cyclops one - it ust has a resistance adjuster and no sensors - got it from a mate for a bargain price.

I've got round to thinking I need some more motivation to train better on it than I have been. It's setup in my gym (part covered garage) and just been watching films on it.

Is there a free / cheap iPhone app that can be used for intervals - that maybe shows a route on the screen and tells you when you go harder and when to back off for intervals?

Also, if it would make things materially better, is there some sort of speed sensor I could attach to the bike that would send info to the app via Bluetooth?

Thanks in advance - hopefully I'm not duplicating the same questions that someone has already asked etc.