well over a year after its initial release. The hidden temperature and humidity sensor in the HomePod mini was uncovered in March 2021, but uses for the hardware weren't immediately clear. However, some early speculation suggested the sensors could be used to detect ambient temperature for use with smart home automations — like controlling thermostat units or adjusting smart blinds.
When Apple debuted the second-generation HomePod with temperature and humidity sensing, the HomePod mini's product page was updated to add the same functionality as well. Though current HomePod mini owners can't take advantage of temperature and humidity-based features just yet, they will be released in the HomePod OS 16.3 update. Both devices have the temperature and humidity sensor which, when activated, will be able to detect the metrics in real-time. Aside from simply notifying the of temperature and humidity levels, HomeKit automations can be used to activate certain functions when the right conditions are met.
How Temperature Sensing Works (& When It Won't)
Temperature and humidity sensing is designed for home use in "indoor, domestic settings." It's optimized for conditions when ambient temperatures are between 15 degrees Celsius (59 degrees Fahrenheit) to 30 degrees Celsius (86 degrees Fahrenheit) and relative humidity is between 30 percent to 70 percent, according to Apple. After the second-generation HomePod is first started up, the device will need some time to calibrate the inbuilt sensors before starting to provide temperature and humidity data. The same principle applies to the HomePod mini, but s will have to wait for a HomePod OS update to activate the sensors. Once the smart speaker has been updated, it too will require a brief calibration period before displaying data.
Since most HomePod devices are kept in the same place and are connected to power constantly, the calibration requirement shouldn't be an issue. Both devices should continue to show temperature and humidity data following the initial setup or update process without the need for routine calibration, provided they remain powered on. If the device is restarted or reset, s can expect the HomePod to recalibrate each time.
Apple warns that accuracy may decrease when music has been playing for extended periods of time, presumably because the HomePod will release its own heat while playing music. Regardless, temperature and humidity sensing is a HomePod feature that can spur creative and intuitive HomeKit automations with other smart home products.
Source: Apple