After coming up with our design proposal, our team met up to discuss the plan for the next ten weeks. We set some basic parameters for how we are going to build our device so that we could then figure out a schedule that will allow us plenty of time to build, program, and test our wearable fall detector prototype.
How will it be built?
Our initial thought was that we might put the accelerometer in something like a necklace, and have it connected to the microcontroller, battery, etc. in a pocket or on a belt clip. But as we discussed the problem, we decided that a guiding principle should be "the simpler, the better". After all, this device needs to be as user-friendly as possible, and having wires running all over one's body may not be comfortable or easy to use. So our design now has all the components incorporated into a monolithic device that will be worn like a small backpack. Of course, a production version of this technology could be much smaller!
What parts will we need?
Besides the components in the challenge kit, we will need two main items. First, a harness or backpack to make the device wearable. We purchased part of a modular backpack system from a military surplus store which we think will work with some modifications (some straps will need clips added to them, etc.) Second, because we want the device to be able to communicate with emergency services or a caretaker, it needs a GSM module to connect to a cell network. We ordered this part online and it should be arriving next week.
What comes next?
Barring any unforeseen complications, the physical construction of the device should be straightforward and we hope to be finished by week 4. Concurrently, we will begin writing the code that will allow it to detect a fall via accelerometer data, and the code for talking to the GSM module. Once construction is finished, we hope to have the coding done within another 2-3 weeks. After that, we will thoroughly test the device to minimize false positives as much as possible. This will involve getting real-world data by having people (ourselves or volunteers) fall in various ways - onto foam pads, of course! Obviously we don't want to risk injury.
Unboxing the project kit!