Piezoelectric transducer frequency
You can use the BMN31K512 with a piezoelectric transducer operating at either 1.7MHz or 2.4MHz frequency. Adjust the on-board frequency switch to match the frequency of the piezoelectric transducer you are using (refer to the orange arrow icon of the below picture). For instance, if you are using a piezoelectric transducer with a frequency of 1.7MHz, ensure that the switch is set to 1.7MHz before powering on.
Water shortage detection
The BMN31K512 also provides a water shortage detection function which can be disabled (refer to the yellow arrow icon of the below picture) and a function interface.
This function is used to detect water shortages in the atomizer and can prevent the product from abnormal operation or damage.
As the capacitance values for empty and full water levels differ, a capacitive touch key is used to detect changes in capacitance values and determine whether there is a water shortage.
Generally, a spring touch sensor with a base is used as the sensor, and it needs to be placed on the bottom of the sink. Please be aware that it is important to prevent the base from contacting with water when designing the sink mechanism. Otherwise the detection may be inaccurate.
The product offers the calibration function for water level detection. It is easy to set up this function. Users only need to design the sink mechanism, refer to the datasheet for wiring details, and then detect water level by using a key or software command. The product stop atomizing when detecting a water shortage.
Two operation modes
The product provides two operation modes, stand-alone mode and networking mode.
- Stand-alone mode: connect a 10kΩ variable resistor to the VR pin and then enter this mode. Adjust the resistance value to control the atomizing power and atomizing level (5W~10W).
- Networking mode: connect the product to a development board, such as BM53A367A, via BMCOM. Adjust atomizing power, atomizing level and atomization period.
When switching from networking mode to stand-alone mode, it is recommended to power off the module for at least 50 seconds so that the internal capacitor can be fully discharged to avoid being unable to enter stand-alone mode.
- Please connect the piezoelectric transducer before powering on to prevent the product from any damage.
- During the frequency tracking and RGB LED driving processes, the product requires a large current. Therefore, it is recommended to supply 24V power before operation to prevent any malfunction.
