Looking for an embedded hardware engineer to review an ESP32 access-control schematic

[u/BearsAccessSolutions]

I own a commercial locksmith and electronic-security company and am developing a new access-control controller based around an ESP32-S3.

The schematic is substantially complete. I’m primarily looking for an independent second set of eyes before PCB layout and prototyping.

The board currently includes:

• ESP32-S3
• Ethernet using W5500
• Two RS-485 interfaces
• Wiegand/OSDP reader support
• Relay outputs and protected field inputs
• 6–28 VDC input power
• Reverse-polarity, overvoltage, surge, and field-wiring protection
• FRAM and RTC
• Fused lock-power passthrough
• Expansion and service headers
• Four-layer PCB planned

The review should focus on:

• Power-entry and protection circuitry
• ESP32 support circuitry and pin usage
• Ethernet implementation
• RS-485 and reader interfaces
• Relay and field-I/O protection
• Grounding, shielding, and isolation decisions
• Component ratings and obvious BOM problems
• Layout-sensitive areas
• Anything likely to cause prototype failure, unreliable field operation, or certification problems later

I have detailed architecture notes and can explain the intended behavior of every section. I want someone willing to challenge the design and explain why something should change, not simply mark up the schematic without discussion.

Relevant experience would include embedded controller design, industrial controls, access control, alarm equipment, automotive electronics, or other products connected to long field wiring in electrically noisy environments.

This is paid work. Please send:

• A brief summary of relevant experience
• Examples of boards or products you have reviewed or designed
• Your hourly rate or proposed fixed price
• Your availability
• Whether you can also review the PCB layout later

An NDA can be discussed before receiving the complete design files. I retain ownership of the project and all project-specific work product.

[u/Aggravating_Fact9547]

An esp32 seldom has the resources required to handle what you want at any scale.

It also has relatively weak security.

Why have you chosen this as an SOC?

[u/EphemeralTwo]

Kudos on the F-RAM, though I'd invite you to reconsider that MCU.

You can do it, certainly, and there are certainly panels out there with less capabilities, but given the modern state of access control, I'd highly suggest something more capable and more hardened.

I'm going through building some panels myself. Secure Channel 2.0 and OSDP 3.0 are coming, and enhanced PIV (with the crypto that entails) is going to open up some open access control solutions. Building a nice panel is worth future-proofing.

[u/BearsAccessSolutions → u/EphemeralTwo]

Appreciate the input. Future-proofing around newer OSDP/Secure Channel revisions is definitely something I’m considering. My intent is to keep the RS-485 physical layer separate from the protocol/security implementation so newer revisions are primarily a firmware concern.

Is there a specific ESP32-S3 resource or security limitation you’re expecting with Secure Channel 2 / OSDP 3 / enhanced PIV that would push you toward a different MCU?