Wireless digital intercom based on GDF350

This solution is based on the GD32F350 Cortex-M4 core MCU as the main control, and the MIC part uses the MAX-9814 module. It is a low-cost, high-performance microphone amplifier with automatic gain control (AGC) and low-noise microphone bias chip. The radio frequency part uses the 2.4G wireless transmission module of NRF24L01, which is a single-chip wireless transceiver chip working in the 2.4~2.5GHz world-wide ISM frequency band. It has extremely low current consumption: when working in transmit mode, the transmit power is 0dBm. The current consumption is 11.3mA, 12.3mA in receiving mode, and the current consumption is even lower in power-down mode and standby mode. The operating rate is up to 2Mbps, which is more than enough to cope with 64kbps G711 encoding and 16kbps ADPCM encoding. The display part uses a 0.96-inch OLED module as the display interface. It has the advantages of ultra-fast response speed and thinness, with a resolution of 128*64 and a variety of interface methods. The module provides a total of 5 interfaces including: 6800 , 8080 two parallel interface modes, 3-wire or 4-wire SPI interface, and IIC interface mode.

Schematic PCB

Ultrasonic standing wave axial suspension moving device

With the in-depth research of ultrasonic levitation technology by domestic and foreign scholars, ultrasonic levitation devices have developed from expensive horns and other equipment to structures composed of general-purpose commercial ultrasonic transducers. Combined with 3D model printing technology, any scientific researcher and Electronics enthusiasts can use these components to make ultrasonic levitation devices to facilitate related acoustic research. This technology was published in AIP Publishing by Asier Marzo et al. Based on its model, this design changes the main control MCU, uses the timer inside the MCU to generate accurate PWM waves, and improves the software so that the ultrasonic device can move the suspension stably during the axial suspension movement. Small objects in multiple nodes.

Schematic PCB