We made a number of important design decisions, and a couple of changes.
- Sensors: Originally we intended to have devices have both sensing and actuation capabilities. What this effectively means is that we would need to both read from and write to devices. Either we would need a shim to control a premade device, or we would need to build it from scratch. The first is very difficult, and the second is unnecessarily time consuming. As such we decided to split the funcionality. Devices will now be <i>either<i> sensing or actuation. That way we can make a simple shim for actuation devices, and it just turns it on or off, and then we buy off the shelf sensors that are intended to be read from. This makes the whole system design much simpler without giving up functionality.
- Protocol: When considering different protocols, we were considering bluetooth (BLE) and wifi. While using BLE would allow the system to function without the router, it would introduce further difficulties. The main difficulty is that BLE is not very good over large distances. Given our use case, it’s very possible that devices are separated by as much as 50 feet (across a house). This would impede the functionality. As such we decided on wifi
- PCB design: We decided against designing our own PCB and custom mamking devices. As discussed above in the “sensors” section, we can achieve the same results by using a simple device shim. As such, we cut PCB design out.
We don’t believe that these changes will incur any costs. This is because all the changes are geared towards simplifying the design while maintaining fucntionality. As such, it should be easier to actually implement.
One other thing we’d like to note is that over the past couple weeks, we’ve made a lot of progress as a group on how to properly go through the design process. Previously, we had a backwards approach. We went in with a set of technologies we wanted to use, and tried to shape our use case around it. Over the past couple weeks, however, we’ve started to tackle it from the opposite direction. We sat down as a group and defined in great detail a couple use cases for our end product. Working from there, we rehashed the requirements, comparing them against those from our proposal. The, using those requirements, we sat down and actually researched different technologies.
