- Sound painting
Maybe the frequencies of sound along with some other parameters could be combined with physical motion to act like a brush and make a painting
- Clock Facebook timeline
Use a physical clock to navigate through the Facebook timeline
- Tie sound with pictures / cameras
Audio triggers can be used to control the focus and shutter of cameras. It would be cool to have some kind of audio signal to remotely control a camera. This could be further extended to automate picture taking, where sound signals could act as "program" or "code". From an archiving viewpoint, sound could be tied together with pictures, and patterns of picture-taking could be discovered and maybe prove to be useful. From the artistic viewpoint, sound could be visualized to make a 3D object.
- Touch to smell
Think of this as Augmented reality for smells. A simple example would be , touch a nametag of some food item to smell it. This could help make buying decisions. Such an approach could also help make for a more complete experience by means of smells of existing objects,conditions and smells at the time.
Use your mobile phone as a mouse. Hook it up with your computer using Bluetooth (preferable) or Internet (depends on the connection then) (Mobile Mouse Pro on Google Play Store does this, I guess)
- Chat troller
Write an automated script that will bug people automatically when they come online on Facebook, Gtalk etc. Schedule a ping every once in a while,and randomly choose from a predefined set of messages you want to troll with
- Hardware hacking : Add flashlight support to phone camera
Add an external flash to phone cameras which do not have flash. Needs messing with phone hardware (optional) AND mobile app development or firmware hacking
Create a corpus of common SMS lingo and their English equivalents. Now, since you cannot change the language people use, change it for yourself. This script could reside on your machine and auto-replace the chat lingo with valid English words and save you rage.
- Book copier
Photocopying books is a big hassle when you have to turn the book upside down and flip the pages, especially for heavy books. A topside scanner would solve that.
- Virtual DJ
Synchronized earphone party, controlled by a central server over WiFi which streams music, or via a small local FM transmitter. As a step ahead, build an interface that allows for feedback about the mood, and requests.
- Remote Wipe over SMS
Send an SMS, and the phone remotely wipes itself, based on what keyword you send it. Use it to wipe contacts, bookmarks,Internet history,SMS on your smartphone. This feature already exists in a few antivirus apps. Should be possible only for Smartphones
- Charger switch
Phones stop charging themselves by software controls when battery is full. This wastes a little power and also messes with the phone battery if you leave the phone for charging at night. Have a small physical plugin that switches off power supply,maybe by means of a relay, to physically disconnect the phone.
- Sound limiter
Control how loud the sound on speakers or headphones can get, in decibels, not in percentage. Useful for restricting loud sounds.
- SOS App
An app that automatically messages, emails,calls and uses any other means of communication you want to integrate, to shout out to your trusted ones in case you need help in an emergency, at the press of a button.
Auto-away indications on chat are normally based on timeouts on the device. They do not account for activity on other devices. Have a small system that figures out if you are inactive on all devices or just some, and then put an Away notification accordingly
- Meeting management on SMS
Create and manage meetups over SMS, independent of what OS your phone is running. Know who's coming, RSVP to meetings,create meetings. Attend all meetups you want to,and none that you don't want to. Involves using SMS APIs and a web application
- Pen Drive plug-n-copy
Have a small attachment with a USB controller chip that will let you copy files off devices onto pen drives plugged in at the other end, without needing a computing device in between.
- Grab that screen
Get access to a device by just pointing your phone at that screen. Eg : Point your phone camera at your laptop screen, and then start using the laptop screen and the laptop from your phone
- Facebook for programmers
Modify / integrate the Facebook UI so that it merges with your programming environment. Distractions are no longer a distraction, but embedded into your programming environment.
Have a small physical mechanical + electrical assembly that can let you transfer a device running on AC power from one outlet to AC power on another outlet, without losing power in between and without needing a DC source
- Guess who
Train a Machine Learning bot with chat logs of multiple people, and then given a test sentence, predict who is most likely to have made that statement
- Secret Exchange Service
Have a service that will let people exchange secrets simultaneously. The entire point of the exercise is to ensure that the secrets will be revealed only if both parties have put in valid (?) secrets
- What nonsense bot
Make a robot on twitter that listens to a particular variety of tweets and tweets "What nonsense" in response
- Shared listening
Give control of your music library to others so they can choose music for you live. You will never have to decide again.