Completed Schematic with USB-C PD, 3.2gen2 support, and 2s-4s LiPo battery charging
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Overview:
This project uses an array of ultrasonic transducers emit a directional sonic beam which will cause the sound to appear to originate from the target.
Description:
This project allows an array of 91 Ultrasonic Transducers (TCT40-16T) arranged in a hexagonal pattern to transmit a 40khz directional sonic beam, modulated using software-based FM, which will demodulate upon hitting a target, resulting in the sound appearing to originate from the target.
Features:
ESP32 WROOM 32E and ESP32S2 microcontroller compatibility
Youtube Link to MP3 File Streaming
12-Bit DAC Channel control using software-based frequency modulation
Software MP3 File Decoding + Decomposition
Audio file buffering for MP3 file conversion using DAC Channel
Selectable Carrier Frequencies and Waveforms
Dual power inputs USB-C or LiPo Batteries with smart power switching
USB-C Power Delivery controlled by microcontroller (5-100W)
Rechargable battery charging circuit (LiPo, Li-ion, NiMH, NiCd, LiFePO4) (2s-4s)
MQTT Protocol for IoT audio integration
PCB Status LED Control
Decoupling capacitors and ESD diodes for high voltage, overcurrent, and reverse polarity protection
Expansion slots for future PCBs (sound reactive lighting, collumating lasers, external DAC up to 32-bits)
Impedance matched traces for maximizing power efficiency
Threaded rod inserts for 3D Printed handle and acoustic lens attachments
Use of modal frequency analyses and generative design to select PCB thickness and create mechanical structure design to reduce vibrations
Overview:
This project uses an array of ultrasonic transducers emit a directional sonic beam which will cause the sound to appear to originate from the target.
Description:
This project allows an array of 91 Ultrasonic Transducers (TCT40-16T) arranged in a hexagonal pattern to transmit a 40khz directional sonic beam, modulated using software-based FM, which will demodulate upon hitting a target, resulting in the sound appearing to originate from the target.
Features:
ESP32 WROOM 32E and ESP32S2 microcontroller compatibility
Youtube Link to MP3 File Streaming
12-Bit DAC Channel control using software-based frequency modulation
Software MP3 File Decoding + Decomposition
Audio file buffering for MP3 file conversion using DAC Channel
Selectable Carrier Frequencies and Waveforms
Dual power inputs USB-C or LiPo Batteries with smart power switching
USB-C Power Delivery controlled by microcontroller (5-100W)
Rechargable battery charging circuit (LiPo, Li-ion, NiMH, NiCd, LiFePO4) (2s-4s)
MQTT Protocol for IoT audio integration
PCB Status LED Control
Decoupling capacitors and ESD diodes for high voltage, overcurrent, and reverse polarity protection
Expansion slots for future PCBs (sound reactive lighting, collumating lasers, external DAC up to 32-bits)
Impedance matched traces for maximizing power efficiency
Threaded rod inserts for 3D Printed handle and acoustic lens attachments
Use of modal frequency analyses and generative design to select PCB thickness and create mechanical structure design to reduce vibrations
Completed Layout (Back)
Completed Layout (Front)
Simulations for vibrational frequencies of each PCB using modal frequency analysis and finite element analysis
Left: Standard 1.6mm thickness Right:Thinner 1mm thickness
Note that the left simulation is far more uneven than the right, leading to possible damage due to high vibrations. This is why I opted for 1mm PCBs.
3D Model of PCB prior to production
Progress:
PCBs arrived from JLCPCB
Accompanying Stencil for smaller UQFN and USB-C components
After using the stencil to apply solder paste, I peeled off the stencil and added every component.
Here you can see the pcb being placed into the oven for reflowing.
Board just after coming out of oven, some parts were not properly soldered and through hole components not added
Board after touch-up and adding THT components. The board is almost fully functional, with the exception of code and ultrasonic transducers.
Probing PCB to measure modulated wave successfully
We can see the modulated waves in more detail here. The green signal is a 4khz sine wave, while the yellow signal is the output 40khz square wave modulated with a 1khz sine wave.
Finished PCB!
The fully assembled PCB rear view
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