Embedded Files
Overview
Overview
A ESP32 powered Bluetooth record player with a LED screen. Handles the input voltage from a stylus (~3mV) and amplifies it to play on a speaker. Also can control the speed of the record player turntable brushless DC motor.
A ESP32 powered Bluetooth record player with a LED screen. Handles the input voltage from a stylus (~3mV) and amplifies it to play on a speaker. Also can control the speed of the record player turntable brushless DC motor.
Features
Features
Power
Power
19V Barrel Jack input
16V LDO regulator
5V, 3V Buck regulators
5V USB-C input
Diode Or'ing w/the 5V buck regulator
Compute
Compute
ESP32-S3-WROOM-1-N4 microcontroller
SSD1306 LCD screen that graphs out the input of the ADC phono pre-amp signal as a sine wave.
I2C communication
Sense
Sense
PCM1808PWR analog to digital converter to convert the record player stylus pre-amp analog input to a digital signal (for both the Bluetooth output for a Bluetooth speaker and the LCD screen)
I2C communication
Actuation
Actuation
3x AOZ9510QI to implement a Brushless DC Motor controller to drive a BLDC motor @ 16V.
PWM input controlled
Full Bridge
5 pin connector for a BLDC w/an inbuilt motor speed controller
Schematic
Schematic
Root Schematic (Key Features: ESP32 S3 + Boot/Reset Buttons, USB-C Receptacle, LCD Screen Connector, MCU Breakout Pins)
Voltage Regulators
Audio Amplifiers
ADC
Motor Drivers
Bill of Materials
Bill of Materials
$50 a board
Layout
Layout
Front Copper Layer
Back Copper Layer
Bringup
Bringup
Two fully populated boards
Firmware
Firmware
PXL_20241210_012433192.TS.mp4Working LCD Screen
Final Thoughts
Final Thoughts
Progress:
Progress:
Completed Portions
All components soldered and not shorted
All three voltage regulators work (16.5V, 5V, 3.3V)
USB-C connected to ESP32 and can write firmware
Screen can display
Working Progress
Debugging Phono Preamp gain
Power amplifier gain (not high enough)
Debug the motor controllers with firmware to be developed
Firmware for controlling the screen and bluetooth
Next Steps:
Next Steps:
Debugging
Debug the preamp and power amplifier and increase the gain by adjusting feedback resistor
Debug the motor drivers (maybe need to have external motor drivers and connect them to headers?
Connecting External Components to the Board:
Connect components such as LED screen and speaker to pin headers on the board
Purchase a turntable stylus and brushless DC motor to connect to board
Mechanical Design:
Design a box to hold the record player and to place the turntable on
Make it out of wood and some 3D printed components
Mount the PCB to box with M3 screws
Integrate it with existing components connected to our PCB, such as the LED screen and speaker
Volume/Speed control with buttons and extra MCU pins?
Learnings
Learnings
Be careful choosing certain IC packages (and footprints)
QFN package with tiny bottom mounted terminal pads are extremely hard to hand-solder, especially with Supernode soldering irons
Do more calculations and circuit simulations on SPICE for the amplifiers
Consider noise and other factors
Place USB-C to write data to the ESP32-S3 closer so there is less error with D+ and D- connections
Take into consideration mechanical design while designing PCB for better component placement
Add status LEDs to indicate when the ESP32-S3 is on
Add test hooks for the power rails for external power supply testing
Put solder jumper pads in-between different sections to have isolate different sections (such as the motor drivers)
Thank you for reading through our project! :D
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