Indoor Industrial Measurement Device
Budget: ₹1,500 – ₹12,500 INR
I am looking for an experienced hardware design engineer to develop a production-grade industrial controller PCB based on the ESP32-S3.
This is not a hobby project. The expectation is a robust, industrially reliable design with proper isolation, analog accuracy, and manufacturability in mind.
A detailed Hardware Requirement Document (HRD) is already prepared and will be shared as the baseline reference. The scope is well thought through, but I expect the freelancer to actively review, challenge, and refine the design where necessary.
What This System Does
The system is an industrial measurement and control device with the following capabilities:
* Sensor acquisition (Pressure + Temperature + Humidity via I2C and SPI)
* Continuous 4–20 mA output (primary, always active)
* Continuous 0–10 V output (secondary)
* RS485 (Modbus-ready) communication
* Local UI (mutually exclusive options):
* SPI TFT display OR
* 7-segment display via driver
* SD card logging + EEPROM storage
* Digital IO via IO expander:
* 3 relays (24V, 3A)
* 5 buttons, 5 LEDs, buzzer
* USB for firmware update + debugging
Core Engineering Requirements
This project requires strong experience in industrial electronics, not just embedded boards.
Key expectations:
* Proper domain separation:
* Digital (MCU)
* Analog/sensor (low-noise)
* Isolated field I/O domain
* Galvanic isolation for:
* SPI (DAC side)
* RS485
* Power (isolated DC-DC)
* Design of precision analog output stage:
* 4–20 mA (≤ ±0.1% FS accuracy)
* 0–10 V output
* Use of SPI DAC (≥14-bit resolution) with proper reference design
* Noise-aware PCB layout (critical)
* Industrial protection:
* TVS, reverse polarity, filtering
* EMI-conscious routing and grounding
PCB + Design Expectations
* Minimum 2-layer (open to 4-layer if justified)
* Clear isolation boundary (≥4 mm clearance)
* Clean analog layout (reference, Kelvin sensing, shielding)
* Controlled SPI routing (DAC + display separation)
* Circular PCB (≤ 104 mm diameter)
Deliverables
* Complete schematic (well-structured, labeled)
* PCB layout (industrial-grade)
* BOM with alternates (cost-aware)
* Gerbers + fabrication-ready files
* Assembly notes
* Basic electrical testing
Important Notes
* 4–20 mA output is mandatory and always active
* Isolation is non-negotiable
* TFT and 7-segment displays are mutually exclusive
* Cost optimization matters, but not at the expense of accuracy or reliability
* Any major architectural deviation must be discussed before implementation
Who Should Apply
This project is suited for engineers who have worked on:
* Industrial controllers / PLC-like systems
* 4–20 mA / analog output systems
* Isolated mixed-signal designs
* ESP32 or similar MCU-based hardware
* EMI-sensitive designs
Before You Quote
Please quote only if:
* You are willing to deeply understand requirements before starting
* You are comfortable with iterative discussion and design reviews
* You will share progress regularly (schematic → partial layout → full layout)
* You have worked on similar industrial or analog + isolation projects
* You can explain your design decisions clearly (not just execute)
* You can do it on your own and not outsource or deligate to others
What Happens Next
Shortlisted freelancers will receive:
* Full HRD document
* Clarifications on architecture decisions (DAC choice, isolation ICs, etc.)
* Opportunity to suggest improvements before finalizing design
If you’ve built something close to this before, mention it. That matters more than generic experience.
If you haven’t worked on isolation + precision analog + industrial outputs together, this project will likely not be a good fit.
This is not a hobby project. The expectation is a robust, industrially reliable design with proper isolation, analog accuracy, and manufacturability in mind.
A detailed Hardware Requirement Document (HRD) is already prepared and will be shared as the baseline reference. The scope is well thought through, but I expect the freelancer to actively review, challenge, and refine the design where necessary.
What This System Does
The system is an industrial measurement and control device with the following capabilities:
* Sensor acquisition (Pressure + Temperature + Humidity via I2C and SPI)
* Continuous 4–20 mA output (primary, always active)
* Continuous 0–10 V output (secondary)
* RS485 (Modbus-ready) communication
* Local UI (mutually exclusive options):
* SPI TFT display OR
* 7-segment display via driver
* SD card logging + EEPROM storage
* Digital IO via IO expander:
* 3 relays (24V, 3A)
* 5 buttons, 5 LEDs, buzzer
* USB for firmware update + debugging
Core Engineering Requirements
This project requires strong experience in industrial electronics, not just embedded boards.
Key expectations:
* Proper domain separation:
* Digital (MCU)
* Analog/sensor (low-noise)
* Isolated field I/O domain
* Galvanic isolation for:
* SPI (DAC side)
* RS485
* Power (isolated DC-DC)
* Design of precision analog output stage:
* 4–20 mA (≤ ±0.1% FS accuracy)
* 0–10 V output
* Use of SPI DAC (≥14-bit resolution) with proper reference design
* Noise-aware PCB layout (critical)
* Industrial protection:
* TVS, reverse polarity, filtering
* EMI-conscious routing and grounding
PCB + Design Expectations
* Minimum 2-layer (open to 4-layer if justified)
* Clear isolation boundary (≥4 mm clearance)
* Clean analog layout (reference, Kelvin sensing, shielding)
* Controlled SPI routing (DAC + display separation)
* Circular PCB (≤ 104 mm diameter)
Deliverables
* Complete schematic (well-structured, labeled)
* PCB layout (industrial-grade)
* BOM with alternates (cost-aware)
* Gerbers + fabrication-ready files
* Assembly notes
* Basic electrical testing
Important Notes
* 4–20 mA output is mandatory and always active
* Isolation is non-negotiable
* TFT and 7-segment displays are mutually exclusive
* Cost optimization matters, but not at the expense of accuracy or reliability
* Any major architectural deviation must be discussed before implementation
Who Should Apply
This project is suited for engineers who have worked on:
* Industrial controllers / PLC-like systems
* 4–20 mA / analog output systems
* Isolated mixed-signal designs
* ESP32 or similar MCU-based hardware
* EMI-sensitive designs
Before You Quote
Please quote only if:
* You are willing to deeply understand requirements before starting
* You are comfortable with iterative discussion and design reviews
* You will share progress regularly (schematic → partial layout → full layout)
* You have worked on similar industrial or analog + isolation projects
* You can explain your design decisions clearly (not just execute)
* You can do it on your own and not outsource or deligate to others
What Happens Next
Shortlisted freelancers will receive:
* Full HRD document
* Clarifications on architecture decisions (DAC choice, isolation ICs, etc.)
* Opportunity to suggest improvements before finalizing design
If you’ve built something close to this before, mention it. That matters more than generic experience.
If you haven’t worked on isolation + precision analog + industrial outputs together, this project will likely not be a good fit.