An app that allows children to make magical toys by 3D sculpting and designing a creature. They can take parts from different animals, reshape them, pick colors and such. The app would allow the parent to order the finished creature to be 3D printed or made into a stuffed animal (the app would preview how a stuffed animal version of the creature would look, as not all shapes are possible). The 3D printed creature can be ordered painted or unpainted with a painting kit, so you can have fun painting it with your kids. First Steps: pitch this to parents, see what they think.
Game where you only move if you move in the real world, for kids to be more active. Basically like Pokemon Go, but something that promotes even more activity. For instance, and app that requires you to run around with your phone / tablet in order to collect points and grow your creature, etc. Ok, this isn't a fully formed idea, I am still thinking about this one, but I think it's very important for kids to be more active nowadays. First Steps: think of a compelling gameplay that could involve movement.
Spine alignment app. An app that can look at pictures of your back and your posture, and give you feedback about some of the problems you may have. The app would have a tutorial about how to take pictures and then use heuristics and AI to see who your spine and posture looks. First Steps: see if something like this is already on the market. Does it work? How can it be better.
Oven with smoke detector inside. Ever opened the oven only to let a plume of smoke out? This one would be for you. Option one would be an add on smoke detector that can be placed inside the oven, with a remote beeper. Option two would be a built in model. In both case you know there is a problem before it becomes a real problem. Ability to turn the sensitivity up or down would be a must. First Steps: research ways to detect smoke in a hot environment like an oven (not as simple as it sounds).
Wifi connected oven with complex cooking profiles. Since we are talking about ovens, how about an oven that has a WiFi connection, and can be programmed and operated from a smartphone. The oven can have a bunch of complex cooking profiles, and would even be able to be used for things like reflowing PCB boards, for the inner geek in all of us :) First Steps: see what currently on the market and if there is any demand for such a thing. Start with market research.
Toilet seat that reminds you to get up after 3 minutes. This is a serious problem, especially in today's day and age of smartphones. Sitting too long on the toilet is how you get hemorrhoids, seriously! Any doctor will tell you this. A simple, small, puck like device that double sticky tapes to the bottom of the toilet seat. It would have a spring loaded switch which would activate when someone sits down. After 3 minutes it would start to beep or play music. Time setting can be adjusted by pressing the activation button 5 times in a row quickly and the puck runs on coin batteries that can be replaced. First Steps: check patentability, build a prototype.
Live delay app for looking with your phone around your head or into places you can't see directly. The idea is simple, just an app that continuously takes video and plays it back with a given (user selectable) delay. As soon as you start the app it starts shooting video, and playing that video back with a 10 second delay. First Steps: see if this exists, if not, it should be easy to code up something like this quickly. Monetize with ads or in app purchase.
Used computer charity that takes computers from large corporations as donations. The computers have to be in good working shape, most are. The charity would clean the donated computers, reinstall the OS on them, and preload them with open source learning software, free games, and an offline copy of Wikipedia. The computers would be donated to underprivileged children in US and in other countries. Most of the computers written off by large institutions are in great working shape. First Steps: see if charities like this already exist, if not, look to partner up with existing charities on this project.
Dog supplements company that uses information about your dog's breed and behavior to sell you supplement treats. I have seen companies like this, but none that offer a monthly service. Not sure how beneficial it will be for the dogs, but it would be very profitable for the humans running the company :) First Steps: see what competition is out there. Design marketing plan. Look for a veterinary partner.
A book about a guy (or girl) in the near future, who freezes himself on an automated satellite circling the earth, and unfreezes himself for one year every 50 years. Each chapter in the book describes a one year period of how the world has changed in that time. Could be a fascinating reimagining of a one way time machine. First Steps: Write a character treatments, and possible future worlds.