🏍️ As a biker, the quality of the road goes a long way to the enjoyment of the trip. Using the accelerometer + GPS position could allow to record the vibration occurring in any road and register its quality.

SmartRoadSense is already doing it, but for some reason, is limited to some country.

1. First step would be to gather data.
2. Then build a fast and reliable back-end to serve those data
   2.1. An online map to show data point is cool, but not necessary
3. Integrate it in a pathfinding algorithm (lower limit, average quality ...)
4. Integrate it to the current fashionnable map service

Bonus:

• Adding hard no-go (gravel road, pothole, construction sites ...)

🏙️ Often, while in a city, I want to report something to the authorities (potholes, fallen signs, broken park bench ...) and don't know who to address my demand.

Having and application sending your message to the right person based on your position and demand's type could be great.

Cities could sign-up to the service and define a recipient. People would then be able to take a picture, define a category, add a simple message to it and it would be send alongside GPS coordinate to that recipient.

Leaving every demand public would prevent to much trolling and adding an upvote/downvote system could self administrate the demands. Plus, people would be able to follow the issue resolution.

Bonus:

• Should validate people identity (like AirBnb)
• Promoting well behave user to greater rank (can post comment, more demand per days ...)

⚠️ An esLint plugin could help Pencil.js users to write better code and discover hidden feature of the library.

Possible rules:

• Use shorthand position definition - new Square([10, 20])
• Don't import Math or Image without renaming (will override existing globals) -
  import { Math as PMath } from "pencil.js";
• Don't use string literal to listen to events - comp.on(constant, func)
• Don't assign without .clone for position, vector and color -
  const pos = previous.clone().add(10)
• Use third param isTargeted when listening to draw event - comp.on("draw", func, true)
• Don't call .add function multiple time - comp.add(child1, child2, child3)

Webstorm plugin to manipulate npm with a UI.

🍲 I've never found a great app to keep count of daily calories intake. As humans eat about 3 times a day, the quality of the search for such app should be perfect.
According to the success of programs like Weight Watchers, there's a market for this kind of app.
What could be done to improve the searching of a product in such a large database:

• Bar-code scan (or product scan with writing detection)
• Simplify the DB to reduce it (foods with really close data should be merge)
• Tag food as favorite (we tend to eat the same things)
• Powerful dynamic search (a tree like the classification of the livings)

Then, each product should be filled with every possible information (calories, lipids [saturated], glucides [sugar], fibre, protein ...)
Gamification could push the concept forwards by rewarding user that eat a balanced diet.

Link YouTube video to a street artist with the possibility to send tip. Having the ability to set a geoposition could be great way to allow people to find their artists. And with that being able to do a reverse search and find artist near you.
Add a lot of view to the video of the person filming and a new source of revenue to the artist, win - win?
Not too much problem to scale because not hosting the video.

🔊 I know, it's not a novel project, but I always wanted to do a sequencer.

The interface should reproduce the setup of a sound-designer. Multiple block could be chosen (sequencer, emitter, effect gate ...) and linked together in a visual way to mix sound.
User could choose among a wide variety of existing sound and sample and be able to export the result.

Bonus:

• User could upload custom file (midi, mp3, json ...) to each module

🗃️ The Leitner box is a box of card that will allow you to remember anything forever(ish). By making a daily habit of recalling something, you increase you chance of engrave it in your long-term memory.

Every day, you start by adding a few card to your box (5 to 10). All new cards start at level 1.
Then you pick all card from level which validate !((day + lvl) % (2 ** lvl)) in decreasing order. If you got it right, the card move up one level. Otherwise, it fallback to level 1.
Once a cards reach level 8, it's supposed to be remembered and can retire.

Bonus:

• It's easier to remember a card if it contextual (allow user to add random bit of information to it: text, photo, doodle ...)
• It's easier to go through all cards if everything is smooth and pleasing. Nice colors and animations can help a lot.

🎮 Making a game that you can really play with your friend on the same computer. One is holding the mouse while the other has the keyboard. This will allow two types of interaction with the game and should mean collaboration between the two players.
One idea was a driving/dodging game. Both player need to control a vehicle to the end.
The mouse could be a motocycle (fast and precise) and the keyboard could drive a truck. While the bikes could fire bullets and dodge better, the truck could break through barrier and protect the bike.
This can match old-school driving game with puzzle and cooperation.