I have a poor record with paying for apps, as they often seem to be poor value . If this will do the job it says it seems expensive but I might give it a go . No reviews on the App Store and no lite version for free , well the so called free version doesn’t seem to do anything but generate ads for a stupid looking game . Think I might be better off cutting up the 7 pounds and making a collage of a mountain scene ? That said is there anything on the App Store that allows one to build a simple interface with a few readings from sensors and a few toggle switches ? (Surely there must be? )
You might want to check out netio.davideickhoff.de . I don’t know anything about it (just found it a few minutes ago), but it looks promising.
I’ve created an iPhone “app” using HTML. This was via a imp-based garage door opener project I found on Instructables (www.instructables.com/id/Electric-Imp-Garage-Door-Opener/). I don’t know if it would satisfy your needs, but it may be an option. It does work well for checking and operating our garage doors.