Haptic rain sensor
A system for detecting precipitation is disclosed. In an embodiment, the system includes a capacitive sensor configured to detect a presence of precipitation, a piezo sensor configured to be powered on in response to detection of the presence of the precipitation by the capacitive sensor, and a processor configured to detect a characteristic of the precipitation based at least in part on an output of the piezo sensor. In an embodiment, a method includes receiving a signal from a piezo sensor, sampling the signal at a sampling rate, determining a frequency domain representation of the sampled signal, determining that a magnitude of a resonant frequency associated with the sampled signal meets a threshold, and determining a valid precipitation event based at least in part on the determination that the magnitude of the resonant frequency meets the threshold.
1. A system for detecting precipitation, the system comprising:
a capacitive sensor configured to detect a presence of precipitation;
a piezo sensor configured to be powered on in response to detection of the presence of the precipitation by the capacitive sensor; and
a processor configured to:
detect a characteristic of the precipitation based at least in part on an output of the piezo sensor, and
power down the piezo sensor in response to absence of detected precipitation during a predefined sampling period.
2. The system of claim 1 , further comprising a peak detector, wherein the peak detector wakes the processor in response to pressure detected by the piezo sensor exceeding a threshold.
3. The system of claim 2 , wherein the processor is further configured to:
determine a magnitude of a voltage corresponding to the pressure detected by the piezo sensor; and
determine a size of the precipitation based on the magnitude of the voltage.
4. The system of claim 1 , further comprising a peak detector, wherein the peak detector wakes an analog-to-digital converter in response to pressure detected by the piezo sensor exceeding a threshold.
5. The system of claim 1 , wherein the processor is configured to detect the characteristic of the precipitation based at least in part on an output of the capacitive sensor.
6. The system of claim 1 , wherein the processor is further configured to determine a drop size of the precipitation based at least in part on the output of the piezo sensor.
7. The system of claim 1 , wherein the processor is further configured to determine a precipitation rate based at least in part on the output of the piezo sensor.
8. The system of claim 1 , wherein the processor is further configured to determine a distribution of precipitation sizes based at least in part on the output of the piezo sensor.
9. The system of claim 1 , further comprising an amplifier configured to process an output of the piezo sensor prior to processing by the processor.
10. The system of claim 1 further comprising an analog-to-digital converter configured to convert an output of the capacitive sensor to a digital signal.
11. The system of claim 1 , wherein the processor is further configured to identify a false positive based on a comparison between the output of the piezo sensor and an output of the capacitive sensor.
12. The system of claim 1 , wherein the piezo sensor is provided between the capacitive sensor and the processor.