Hey HN!<p>I’m an NHS doctor and the founder of Pia (<a href="https://www.piahealth.co" rel="nofollow">https://www.piahealth.co</a>) which developed Lungy (<a href="https://www.lungy.app" rel="nofollow">https://www.lungy.app</a>). Lungy is an iOS app that responds to breathing in real-time and was designed to make breathing exercises more engaging and beneficial to do. It’s been just over a year since Lungy launched (here’s the original ShowHN: <a href="https://news.ycombinator.com/item?id=34534615">https://news.ycombinator.com/item?id=34534615</a>) and it's had a huge update and complete redesign. We rebuilt the whole app, and added a real-time 3D soft body solver which gives some really cool interactions like blobs / objects that inflate as you breathe. We also made a version for Vision Pro, called 'Lungy Spaces'.<p>My background is as a junior surgical trainee and I started building Lungy in 2020 during the first COVID lockdown in London. During COVID, there were huge numbers of patients coming off ventilators and patients are often given breathing exercises on a worksheet and disposable plastic devices called incentive spirometers to encourage deep breathing. This is intended to prevent chest infections and strengthen breathing muscles that have weakened. I noticed often the incentive spirometer would sit by the bedside, whilst the patient would be on their phone – this was the spark that lead to Lungy!<p>Since making the first version we’ve made exercises fully customisable (you can dial in exact timings for each breath phase), added new breathing indicators, learning modules, e.g. self-care for anxiety symptoms, and lots of new visuals. The free version gives you access to a new breathing exercise each day, whilst premium ($14.99 per year, $39.99 unlimited) unlocks the full library of exercises, exercise data and visuals..<p>The visuals are mostly built using Metal (a couple use SpriteKit) and there are lots to choose from - boids, cloth sims, fluid sims, a hacky DLA implementation, rigid body + soft body sims - each one reacts to breath and touch. The audio uses AudioKit with a polyphonic synth and a sequencer plays generated notes from a chosen scale (you can mess around with the sequencer and synth in Settings/Create Music). The nice thing about the visuals + audio being generative is that the download size is relatively small with no other downloads. We’re still working on improving the breath detection, using ML - currently, it uses microphone input, with optional camera input to guide positioning.<p>We’re also close to finishing the medical device version - <a href="http://lungy.health" rel="nofollow">http://lungy.health</a> - designed as a pulmonary rehab platform for patients with asthma and COPD, it should hopefully be released in the UK early 2025.<p>Thanks for reading - would love to hear any feedback!<p>Lungy Version 2 here: <a href="https://apps.apple.com/app/apple-store/id1545223887" rel="nofollow">https://apps.apple.com/app/apple-store/id1545223887</a>