So yes, an app for Pranayama. It's not ideal, it would be nice to have more control and be able to set your own ratios and/or time for each section. I want a 1:4:2:1 ratio of 5/20/10/5 seconds but it's a little awkward working out how to do that. I pretty much managed it, eventually, with the Advanced setting set at level 3.
I like using it because I kept losing count and forgetting where I was, especially with Viloma Ujaii. Best of all though is sticking it on at work while repairing, great when your doing something you don't have to think about to much like striping down an old sax.
A 20 second retention gives me enough time to silently chant the Pranayama mantra.
Here's a little demo of how I'm using it. This is the first app. demo I've done so excuse the thumb in all the wrong places. I think it's going for 2.99 GBP
Here's a link to the developers site and more professional demo's
I've settled into a routine now of finishing my practice with Kapalabhati (bellows like breathing) I do 108 of those, split into three, 36 in Padmasana (lotus) then 36 in Utpluthi (Lift up) and another 36 with my arms raised up bent back, hands crossed on my shoulders. I then do ten minutes of Nadi Sodana. I follow that with meditation, ten to twenty minutes depending on how I am for time. In the evening I do the same amount of pranayama, some more chanting and a longer sit.
Nadi Sodana Pranayama
Inhale : 5 seconds. Left nostril
retain : 20 seconds. Chant Pranayama mantra in my head
exhale : 10 seconds. Right nostril
retain : 5 seconds. Engage Locks
This is the Pranayama mantra I use.
And here's a link to Srivatsa Ramaswami teaching the Pranayama Mantra
As well as teaching some other Chants, including the Yoga Sutra's here http://vinyasakrama.com/Chants