1. Carbon Monoxide Sensor
The possibility of such a tiny thing being able to be used to save many lives struck me. Of course, smoke detectors serve a similar purpose, but these can be used to alert even more people to come to others’ aids.
2. Heating pad
Besides heated clothing in the winter, we can use these from keeping food warm to making the toilet seat less painful to sit on during cold mornings.
The Wii Nunchuck takes in many different types of inputs from various kinds of physical interactions, and we can send them easily to Arduinos with this.