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Battery-Powered 2-Layer LM358 Analog Replicator PCB with Dual-Gain Edge Potentiometer and Solid 12 V Ground Plane

Using the Raspberry Pi Pico microcontroller, I was able to design a hearing aid with volume control. The components and a description of why they were used: MCP3008 - CONVERTS ANALOG AUDIO SIGNALS INTO DIGITAL DATA CONVERTED BY THE MICROCONTROLLER MCP4725 - CONVERTS DIGITAL AUDIO SIGNALS TO ANALOG SO THE AUDIO CAN BE OUTPUTTED THROUGH A SPEAKER LM358 - USED TO AMPLIFY WEAK SIGNALS IN THE HEARING AID, REMOVES UNWANTED FREQUENCIES SPU0410LR5HQB - THIS COMPONENT IS A MICROPHONE, SPECIFICALLY CHOSEN BECAUSE IT IS OMNIDIRECTIONAL AND CAN CAPTURE AMBIENT SOUNDS, IT IS A SMALL COMPONENT PERFECTLY USED FOR NOISE REDUCTION, ASSISTING IN CAPTURING CLEAR AUDIO PAM8302AASCR - EFFICIENTLY AMPLIFIES AUDIO, AUDIO SIGNAL FROM DAC (VOUT) IS FED INTO THE INPUT OF THE AUDIO AMPLIFIER, WHICH OUTPUTS IDEAL FREQUENCY AUDIO CEM-1203(42) - SPEAKER WHICH OUTPUTS THE AUDIO AMPLIFIER MODIFIED FEATURE: POTENTIOMETER - WITH THE CCW CONNECTED TO GND, CW CONNECTED TO VDD, WIPER CONNECTED TO PIN 27 OF THE MICROCONTROLLER, THIS FEATURE IS A VOLUME ADJUSTER, WE ARE ABLE TO FULLY TURN OFF AND ON THE VOLUME BY ADJUSTING THE HEARING AID FOR THE IDEAL AUDIO OUTPUT

DIP794W45P254L959H508Q8 https://snapeda.com/shop?store=Arrow+Asia&id=106817 PDIP-8 Texas 2-Channel, 1MHz, industry standard, 32V op amp 8-PDIP 0 to 70 LM358N/NOPB Texas Instruments https://snapeda.com/shop?store=DigiKey&id=106817 https://snapeda.com/shop?store=Mouser&id=106817 None Good Aliases: undefined

- ESP32 DevKitC V4 (microcontroller) - 2x BME280 sensors (temperature, humidity, pressure) - 8ch relay board with 12VDC relays (NO/NC SPDT) - 12VDC power supply - USB connectivity - Various components (resistors, caps, opto couplers, op-amps, motor drivers, multiplexers) - 2x SPDT relay boards (for fan fail-safe) - 4x 2ch bidirectional level controllers (3.3V to 5V) - ESP32 GPIO 21 (SCL) to BME280's SCL - ESP32 GPIO 22 (SDA) to BME280's SDA - ESP32 GPIO 5 (digital output) to 8ch relay board input - ESP32 GPIO 25 (PWM output) -> Fan PWM (0-255 value) - ESP32 GPIO 26 (PWM output) -> Light PWM (0-255 value) - ESP32 GPIO 34 (analog input) -> Tachometer input (0-4095 value, 12-bit ADC) - Add a 5V voltage regulator (e.g., 78L05) to power the ESP32 and other 5V components - Add a 3.3V voltage regulator (e.g., 78L03) to power the BME280 sensors and other 3.3V components - Include decoupling capacitors (e.g., 10uF and 100nF) to filter the power supply lines - Ensure proper grounding and shielding to minimize noise and interference -- Power supply: - VCC=12VD Available, to be used for LM358P - 5V voltage regulator (78L05) - VCC=5V, GND=0V - 3.3V voltage regulator (78L03) - VCC=3.3V, GND=0V - 3.3V voltage regulator (78L03) - VCC=3.3V, GND=0V - Fan PWM boost: - Input (3.3V PWM): 0-3.3V, frequency=20kHz - Output (5V PWM): 0-5V, frequency=20kHz - LM358P op-amp (unity gain buffer) - VCC=5V, GND=0V - R1=1kΩ, R2=1kΩ, R3=1kΩ, R4=1kΩ - C1=10uF (50V), D1=1N4007 - 0-10V signal conditioning: - Input (3.3V PWM): 0-3.3V, frequency=13kHz - Output (0-10V): 0-10V, frequency=13kHz - LM358P op-amp (non-inverting amplifier) - VCC=5V, GND=0V - R5=2kΩ, R6=1kΩ, R7=2kΩ, R8=1kΩ, R9=1kΩ, R10=2kΩ - C2=10uF (50V), R11=10kΩ (1%) ------------------------------------ Fan PWM Boost (3.3V to 5V): 1. ESP32 GPIO 25 (PWM output) -> R1 (1kΩ) -> VCC (3.3V) 2. ESP32 GPIO 25 (PWM output) -> R2 (1kΩ) -> Vin (LM358P) 3. LM358P (Voltage Follower): - VCC (5