The UART will allow the sensor’s settings to be configured on the fly and provides more granular output, such as the estimated distance to target and separate statistics for motion & motionless targets.
Thing is, I don’t need any of that. Once the sensor has been configured, I’d rather just use the single output, as it simplifies things, reduces workload on the MCU and doesn’t use a hardware UART.
The behaviour of the single output isn’t ideal, though. I’ve found it only switches on if the motion target goes above threshold, not the motionless, then only switches off if both modes go below threshold. I’d rather it switched on if motionless is detected, since that ability is the main advantage these sensors have over a PIR. This may leave me with no option but to use the UART.
It would also be nice if the sensor had the ability to switch the radio on & off, but I haven’t seen any evidence of that feature.