You should look at the FitBit website - there are a lot of pictures of the FitBit from concept through manufacturing and test. It is much better than a teardown and shows a lot of information about the manufacturing process.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.