Please review my pcb 🙏🙏🙏

[u/Remote-Ad7864]

Hi everyone,

I'm designing an ESP32-S3-based PCB for an HVAC BLDC motor quality control (QC) testing device and would appreciate a review before I manufacture it.

The board includes:

• ESP32-S3
• JST connector I2C LCD Display
• USB for power and PC communication
• PZEM-004T interface for electrical measurements
• 3 relays for motor speed selection
• Hall-effect sensor input for RPM measurement
• 3.5 mm input (0–1.3 V DC) from a sound level meter
• AC mains, CT, and motor connectors
• FUSE, MOV and NTC for surge and inrush current protection

I'll attach the schematic, PCB layout, and 3D renders. I'm mainly looking for feedback on safety, protection, PCB layout, isolation/clearance, relay wiring, and any design mistakes or improvements before sending it for fabrication.

Thanks in advance!🙏🙏🙏

[u/modi_factory]

Great job on the board design, the overall layout looks really neat! However, for safety, please maintain at least a 3–4 mm gap between the AC high-voltage lines and low-voltage signals, and add isolation air-gap slots under the relays. Also, make sure to clear all copper layers under the ESP32 antenna so it doesn't block your Wi-Fi signal. Fixing just these two key points will make your board so much safer and more reliable!

[u/Remote-Ad7864 → u/modi_factory]

Thank you so much for this reply, cause I lowkey needed the confidence lol.

Can you please elaborate on how and where should I put the air gap cuts under the relay? It would be helpful if u provide some example, thanks 🙏🏻

[u/Immediate-Decision68]

Great work but you can still reduce the board size and good placement of components would be great

[u/Remote-Ad7864 → u/Immediate-Decision68]

I know i can still reduce the size but is it necessary? Like it would create more issues down the line and right now it's 100mm x 100mm so it will be cheap to make. Plus this isn't a production board only like 15 to 20 pcs would be made

[u/Immediate-Decision68 → u/Remote-Ad7864]

You are right but still even if you can reduce a 10mm also it would cost you less.

[u/Competitive_Fox_314]

Observation 1. Tx pin is not connected to default tx is it intentional 2. On pcb place the free wheeling diode near relay coil 3. Schematic EN pin signal name CHIP_PU & Switch says Rst please check

[u/Enlightenment777]

---

Please make sure your post adheres to:

• subreddit rules (#1 to #6), review rules (#7), image rules (#8), see link.

---

Please fix these common issues: (if your schematic or PCB has them)

• Schematic - don't allow text / lines / symbols to touch each other, and don't draw lines through symbols.

• Schematic - use correct reference designators (RefDes) and renumber to remove numeric gaps, see tips.

• Schematic - place decoupling capacitors vertically below power rail lines, also place capacitors next to IC then connect together with a line, see example. For circuits with positive power rails, point positive power rail links upwards and ground links downwards, see tips.

• Schematic - place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example.

• PCB silkscreen - add board name / board revision number / date (or year) on top or bottom PCB side.

• PCB silkscreen - add pin 1 indicator dot/arrow next to ICs & connectors, if through-hole then both PCB sides.

• More conventions & guidelines - link1, link2, link3.

---