failure mode handling could generally be more graceful

[DocSunset]

When one of the I2C sensors is having connection difficulties, the entire device becomes inoperable, without any indication of what's wrong. This makes it difficult to tell when something is amiss, since the behavior is almost the same as a dead battery.

Ideally, when one of the sensors in inaccessible, the firmware should detect this, report it in some fashion (e.g. set all the sensor values to NaN? Or perhaps there should be status signals that can be set appropriately if a problem is detected?), and move on to trying to do the rest of the work that the T-Stick usually does, like reading all the other sensors.