Buying an ultrasonic transducer involves matching technical specifications like frequency and power to your specific application, whether you are building a small hobbyist project or maintaining industrial equipment. These devices use piezoelectric crystals to convert electrical energy into high-frequency sound waves.
. These are low-cost, easy to interface with microcontrollers like Arduino, and typically include both a transmitter and receiver.
A high-power converter for plastic welding applications, found on eBay.