Summer’s all but over, but it’s no less important to stay hydrated. According to the CDC 43 percent of Americans drink fewer than four glasses of water a day, and while the actual amount you should drink varies from person to person, four glasses probably doesn’t cut it. That’s where Caktus, a neat Finnish hardware startup that presented at TechLaunch’s second New Jersey demo day, comes into play. Their mission? To fix that dearth of drinking with an app and a curious sensor that straps onto your water bottle.