There may be more to the HomePod mini than Apple first let on. The smart speaker features a component that the company has yet to disclose, according to Bloomberg. That component is a sensor made by Texas Instruments for measuring temperature and humidity.
iFixit found the 1.5mm by 1.5mm chip hidden away from the mini's other components, suggesting it's not there to measure the device's internal temperature. Apple has reportedly discussed allowing the sensor to share the data it collects with other HomeKit-enabled devices such as fans and thermostats. That's something devices like Amazon's latest Echo smart speakers already do with their built-in temperature sensors. You can use the 2020 Echo to trigger other devices with the help of Alexa routines. Bloomberg suggests Apple could program the HomePod mini to do something similar with HomeKit devices. It could also share the data it collects with thermostats, so you wouldn't have to buy separate sensors for different rooms to heat and cool your home more efficiently.
It's not clear if or when Apple will turn the sensor on. However, the company has done something like that in the past. As Bloomberg points out, the 2008 iPod touch featured a Bluetooth chip that Apple enabled about a year after its release. In more recent memory, Apple updated the HomePod mini to take advantage of its ultra-wideband (UWB) chip for more seamless audio handoffs to and from the iPhone. However, that was a feature that Apple detailed when it announced the device last year.