Why not just use one of the many sensors that research groups and companies have already developed?
There are certainly many wireless accelerometers already out there. However, to our knowledge, none meet the goals of this project for sensors that are sufficiently small to wear 24/7, allow data to get into common mobile phones without special/awkward connections, allow multiple data streams to be streamed to the phone in real time, work robustly and don’t require any manual operation for pairing/rebooting, and can be obtained at the lowest possible cost. The other options tend to be too big or have very limited battery life. They also tend to be quite expensive or difficult to obtain in small and large quantities. Many of the smallest devices do not stream high sampling rate data in real time to the phone. Others use wireless protocols that only work with one or two phone models or that require special add-ons to the phones themselves. There is an important niche for both hobbyists and researchers that no currently available hardware seems to meet.
