You can see it here: https://radar.braintapper.com - it's hosted on the cheapest possible VPS, so it's obviously not scalable (was public for friends and family, but I guess we're all friends here, haha)
The original (buggy) prototype, which was static and stored data in the browser (eventually I added syncing via PouchDb/CouchDb) is here: https://bt-apps.github.io/braintapper_radar/