ESP32 Extension Board Design (4 Analog Inputs, 4 AC/DC SSR Outputs, 4 DC Inputs, I2C Terminals, 24V DC Power, RGB & Status LEDs)
Budget: $30 – $250 USD
ESP32 Extension Board Design (4 Analog Inputs, 4 AC/DC SSR Outputs, 4 DC Inputs, I2C Terminals, 24V DC Power, RGB & Status LEDs, Soft Power-On)
Description:
I am looking for an experienced electronics engineer to design a custom ESP32 extension board with the following specifications for industrial and IoT control applications.
? Features Required:
1. Power Supply
Primary input: 24V DC
Onboard regulator to step down 24V DC to 5V DC
5V output used to power:
Analog input reference
Relay control logic
ESP32 and other onboard components
Must support soft power-on functionality (see below)
2. Analog Inputs (ADC) – 4 Channels
Voltage range: 0–5V
Each channel must have a 3-pin terminal block:
+5V, GND, Analog Signal
Inputs must be scaled and protected for safe use with ESP32’s 0–3.3V ADC
Include buffering, clamping, and filtering as needed
3. AC/DC Solid State Relay Outputs – 4 Channels
Capable of switching both AC and DC loads
Use SSRs with proper isolation and ratings
Each output has its own terminal block
Each relay must include an onboard LED to indicate when it's active
4. Digital Inputs – 4 Channels
Accept 0V (LOW) and 5V–24V DC (HIGH)
Each input must have a 3-pin terminal block:
0V (GND), +5V, Input Signal
Include level-shifting and over-voltage protection for ESP32 compatibility
5. I2C Terminal Blocks
Two 2-pin terminal blocks:
3.3V, GND
SDA, SCL
For connecting external I2C devices
Include pull-up resistors (jumper-selectable preferred)
6. LED Indicators
Relay Status LEDs: One per relay output
RGB LED:
Common cathode preferred
Connected to 3 PWM-capable GPIOs
Used for system status or custom feedback
General Status LED: Connected to any free GPIO for heartbeat/debug
7. Soft Power-On Circuit
Momentary push-button to turn on the board
Uses a latching power circuit (MOSFET-based or equivalent) to supply power to ESP32 and peripherals
ESP32 should be able to turn itself off via GPIO (if needed)
Useful for low-power standby or user-friendly power control
? Target ESP32 Module
Design should be based on the ESP32-WROOM-32 DevKit (38-pin) module
This ensures:
Long-term hardware consistency
Good availability from major suppliers
Stable pinout and community support
ESP32 board can be socket-mounted (female headers) for easy replacement or upgrade
? Deliverables:
Circuit schematic (KiCad, Eagle, or equivalent)
PCB layout (ready for fabrication)
Bill of Materials (BOM)
Gerber files
Optional: 3D render or model of PCB
? Preferred Skills:
ESP32 hardware design
Power electronics (MOSFETs, latch circuits)
Analog signal conditioning
SSR relay control
I2C and GPIO safety
PCB design with terminal block layout
Please include past hardware examples. Suggestions for design improvements or optimizations are welcome.
Description:
I am looking for an experienced electronics engineer to design a custom ESP32 extension board with the following specifications for industrial and IoT control applications.
? Features Required:
1. Power Supply
Primary input: 24V DC
Onboard regulator to step down 24V DC to 5V DC
5V output used to power:
Analog input reference
Relay control logic
ESP32 and other onboard components
Must support soft power-on functionality (see below)
2. Analog Inputs (ADC) – 4 Channels
Voltage range: 0–5V
Each channel must have a 3-pin terminal block:
+5V, GND, Analog Signal
Inputs must be scaled and protected for safe use with ESP32’s 0–3.3V ADC
Include buffering, clamping, and filtering as needed
3. AC/DC Solid State Relay Outputs – 4 Channels
Capable of switching both AC and DC loads
Use SSRs with proper isolation and ratings
Each output has its own terminal block
Each relay must include an onboard LED to indicate when it's active
4. Digital Inputs – 4 Channels
Accept 0V (LOW) and 5V–24V DC (HIGH)
Each input must have a 3-pin terminal block:
0V (GND), +5V, Input Signal
Include level-shifting and over-voltage protection for ESP32 compatibility
5. I2C Terminal Blocks
Two 2-pin terminal blocks:
3.3V, GND
SDA, SCL
For connecting external I2C devices
Include pull-up resistors (jumper-selectable preferred)
6. LED Indicators
Relay Status LEDs: One per relay output
RGB LED:
Common cathode preferred
Connected to 3 PWM-capable GPIOs
Used for system status or custom feedback
General Status LED: Connected to any free GPIO for heartbeat/debug
7. Soft Power-On Circuit
Momentary push-button to turn on the board
Uses a latching power circuit (MOSFET-based or equivalent) to supply power to ESP32 and peripherals
ESP32 should be able to turn itself off via GPIO (if needed)
Useful for low-power standby or user-friendly power control
? Target ESP32 Module
Design should be based on the ESP32-WROOM-32 DevKit (38-pin) module
This ensures:
Long-term hardware consistency
Good availability from major suppliers
Stable pinout and community support
ESP32 board can be socket-mounted (female headers) for easy replacement or upgrade
? Deliverables:
Circuit schematic (KiCad, Eagle, or equivalent)
PCB layout (ready for fabrication)
Bill of Materials (BOM)
Gerber files
Optional: 3D render or model of PCB
? Preferred Skills:
ESP32 hardware design
Power electronics (MOSFETs, latch circuits)
Analog signal conditioning
SSR relay control
I2C and GPIO safety
PCB design with terminal block layout
Please include past hardware examples. Suggestions for design improvements or optimizations are welcome.