Industrial ESP32-S3 IoT Pulse Controller – PCB Design (V1 Pilot)

Project Overview
We are developing a production-oriented V1 Industrial ESP32-S3 based IoT Pulse Controller for self-service car wash and vacuum stations.
The device:
• Receives secure commands from backend firmware (already under development)
• Generates deterministic coin-pulse outputs
• Operates in noisy industrial environments (motors, pumps, inductive loads)
• Must function reliably in outdoor conditions (temperature variations, humidity)
This is V1 Pilot, not mass production yet — but hardware must be stable, clean, and field-ready.
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Mechanical & Environmental Requirements
• The PCB must fit inside an IP65-rated enclosure
• Target environment:
o Outdoor installation
o Moisture exposure
o Temperature range approx. −20°C to +50°C
• Mounting holes required
• Target PCB size must be proposed before layout (compact design preferred)
• Connector orientation must be practical for industrial wiring
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Scope of Work
The selected engineer will deliver:
• Complete industrial-grade schematic
• 2-layer PCB layout (mandatory for V1 unless strong technical justification)
• Industrial component selection (extended temperature range preferred)
• EMI-conscious layout
• Manufacturing-ready files
• One minor revision after first prototype testing (if needed)
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Mandatory Hardware Requirements
Power & Protection
• 24V DC input
• TVS diode on power input
• Reverse polarity protection
• Fuse or resettable PTC
• Bulk + ceramic decoupling strategy
• EMI mitigation strategy (must be justified in design document)
• Industrial DC/DC converter (24V → 5V)
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Core System
• ESP32-S3 module (final MPN confirmed before layout freeze)
• Proper RF layout with U.FL or PCB antenna
• Dedicated programming header (UART or pogo-pad production flashing)
• Clean separation between power and logic domains
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Outputs
• PhotoMOS SSR output
• Mechanical relay (SPDT)
• Opto-isolated open-collector output
• Protection against inductive spikes
• Clean signal routing for precise pulse output timing (no unintended delays or coupling)
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Reliability
• Brownout-safe reset routing
• Internal watchdog supported
• External watchdog optional (engineer must justify if required)
• Adequate creepage and clearance for 24V DC systems
• Thermal consideration for DC/DC and relay area
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RF & Layout Requirements
• Solid ground plane
• Proper antenna keep-out zone
• Minimized high-current loop areas
• EMI-aware routing and decoupling placement
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Deliverables
• Schematic (PDF + native CAD files)
• PCB layout source files
• Gerber files
• Drill files
• BOM with exact manufacturer part numbers
• Pick & Place file
• Assembly drawing
• Production notes for turnkey assembly
• Short design justification document (EMI + power strategy)
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Definition of Done – Hardware V1
• Schematic approved
• PCB passes ERC/DRC clean
• All components verified as purchasable
• Ready for turnkey PCB manufacturing
• Suitable for enclosure inside IP65 housing
• Production flashing method confirmed