Circuit Documentation

Summary

The circuit in question appears to be a multifunctional embedded system based on the ESP32 microcontroller. The ESP32 serves as the central processing unit, interfacing with various peripherals including a voice recognition module, an electret microphone amplifier, a load cell interface (HX711), an I2C LCD screen, a membrane matrix keypad, a buzzer, a microSD card socket, and two servo motors. The system is powered by a 5V battery. The ESP32's GPIO pins are used to communicate with these components, either through direct digital I/O or communication protocols such as I2C.

Component List

ESP32 (30 pin)

• A 30-pin microcontroller with Wi-Fi and Bluetooth capabilities. It is the main processing unit of the circuit.

Voice Recognition Module

• A module capable of recognizing voice commands and interfacing with the ESP32 via serial communication.

Adafruit MAX9814 Electret Microphone Amplifier

• An automatic gain control microphone amplifier used to amplify the signal from a microphone for the ESP32 to process.

HX711 - Bridge Sensor Interface

• A precision 24-bit analog-to-digital converter (ADC) designed for weigh scales and industrial control applications to interface directly with a bridge sensor.

I2C LCD 16x2 Screen

• A 16x2 character LCD display that uses the I2C communication protocol for displaying information.

4X4 Membrane Matrix Keypad

• A 16-button keypad that provides user input to the microcontroller.

Buzzer

• An electronic buzzer for audio feedback, driven by a digital signal from the ESP32.

MicroSD Card Socket

• A socket for a microSD card that allows the ESP32 to read from and write to the card.

5V Battery

• The power source for the circuit, providing 5V to the components.

Servo (x2)

• Two servo motors that can be precisely controlled by the ESP32 to move to specific angles.

Wiring Details

ESP32 (30 pin)

• D34 connected to Adafruit MAX9814 Electret Microphone Amplifier OUTPUT
• D35 connected to MicroSD Card Socket DO
• D32 connected to HX711 DATA (OUT)
• D33 connected to HX711 SCK - CLOCK (IN)
• D25, D26, D23, D19, D18, D5, D4, D2 connected to corresponding pins C3, C4, C2, C1, R4, R3, R2, R1 of the 4X4 Membrane Matrix Keypad
• D27 connected to MicroSD Card Socket CS
• D14, D12 connected to pulse pins of the two Servo motors
• D13 connected to MicroSD Card Socket DI
• D22 connected to I2C LCD 16x2 Screen SCL
• TX0 connected to Voice Recognition Module RDX
• RX0 connected to Voice Recognition Module RTX
• D21 connected to I2C LCD 16x2 Screen SDA
• D15 connected to MicroSD Card Socket CLK
• GND connected to common ground net
• 3V3 connected to Adafruit MAX9814 Electret Microphone Amplifier VDD

Voice Recognition Module

• GND connected to common ground net
• VCC connected to common power net
• RDX connected to ESP32 TX0
• RTX connected to ESP32 RX0

Adafruit MAX9814 Electret Microphone Amplifier

• GND connected to common ground net
• VDD connected to ESP32 3V3
• OUTPUT connected to ESP32 D34

HX711 - Bridge Sensor Interface

• DATA (OUT) connected to ESP32 D32
• SCK - CLOCK (IN) connected to ESP32 D33
• GND - GROUND connected to common ground net
• 3.3/3.5V Supply connected to common power net

I2C LCD 16x2 Screen

• SCL connected to ESP32 D22
• SDA connected to ESP32 D21
• GND connected to common ground net
• VCC (5V) connected to common power net

4X4 Membrane Matrix Keypad

• R1, R2, R3, R4, C1, C2, C3, C4 connected to corresponding ESP32 pins D2, D4, D5, D18, D19, D23, D25, D26

Buzzer

• PIN connected to common power net
• GND connected to common ground net

MicroSD Card Socket

• DO, CS, DI, CLK connected to corresponding ESP32 pins D35, D27, D13, D15
• GND connected to common ground net
• 3V connected to common power net (if 3.3V is required)
• 5V connected to common power net (if 5V is required)

5V Battery

• + connected to common power net
• - connected to common ground net

Servo (x2)

• gnd connected to common ground net
• vcc connected to common power net
• pulse connected to corresponding ESP32 pins D14, D12

Documented Code

No code was provided for the microcontrollers in the circuit. The documentation of the code would typically include descriptions of the functions, the logic behind the main loop, and any interrupt service routines or handlers. It would also detail how the code interacts with each of the components, including initialization of peripherals, reading from sensors, writing to displays, and handling user input.