Now this really is a brilliant idea.
You attach them to things that you want to remember to do and using an app set a certain frequency – so you put it on a pill bottle and tell the app to remind every, say, 4 hours. You then tap the droplet to acknowledge that you have done it. Brilliant. Watch the video.
More about the Kickstarter, https://www.kickstarter.com/projects/653567732/droplet-the-smart-reminder