Board Overview
The Omi uses three interconnected PCBs:| Board | Function | Latest Version |
|---|---|---|
| Mainboard | nRF5340 SoC, nRF7002 Wi-Fi, microphones, IMU, flash, battery management | v1.2 |
| Charger Board | Magnetic dock with pogo pins, USB-C power, ESD protection | v1.0 |
| FPC | Flexible cable connecting mainboard to charging contacts | v1.0 |
- Mainboard
- Charger Board
- FPC
The main PCB carries all active electronics.Key ICs:
Files:
| IC | Function |
|---|---|
| nRF5340-CLAA | Dual-core Bluetooth LE SoC (application + network cores) |
| nRF7002-CEAA-R7 | Wi-Fi 6 companion IC |
| CSNP4GCR01-DPW | 8GB NAND Flash |
| LSM6DS3TR-C | 6-axis IMU |
| BQ25101YFPR | Li-Ion/Li-Poly battery charger |
| TPS628438YKAR | DC-DC buck converter |
| 2x MMICT5838-00-012 | TDK T5838 PDM microphones |
| File | Description |
|---|---|
schematic.pdf | Full schematic |
gerbers/ | Gerber + drill files for PCB fabrication |
altium/ | Altium Designer source project |
How to Order PCBs
Upload the Gerber ZIP to any PCB manufacturer. Use the exact specs below per board:| Parameter | Mainboard | Charger Board | FPC |
|---|---|---|---|
| Layers | 4 (F.Cu, In1.Cu, In2.Cu, B.Cu) | 2 | 2 |
| Material | FR4 | FR4 | Polyimide (flex) |
| Thickness | 0.6mm | 1.0mm | 0.3mm |
| Board Size | 21.0 x 21.0 mm | 13.0 x 20.0 mm | 29.3 x 12.5 mm |
| Surface Finish | ENIG (immersion gold) | ENIG | ENIG |
| Min Trace/Space | 0.076mm / 0.076mm (3 mil) | 0.2mm / 0.127mm | 0.254mm / 0.1mm |
| Solder Mask | Both sides | Both sides | Both sides |
| Copper Weight | 1 oz outer, 1/3 oz inner | 1 oz | 1 oz |
View Full BOM
See the complete Bill of Materials with all 88 components
First Power-On Checklist
Visual Inspection
Check for solder bridges on QFN pads with a microscope or loupe. Verify all passives are placed correctly (check orientation of polarized capacitors).
Power Rails
Connect bench supply (set to 3.7V, current limit 100mA). Measure VBAT (3.7V at battery input), VDD_nRF (1.0V for nRF5340 core), and VDDH (3.3V for nRF5340 I/O).
Flash Firmware
Connect SWD debugger (J-Link or nRF DK). Flash using nRF Connect SDK. See firmware guide.
Troubleshooting
Board doesn't power on
Board doesn't power on
Check BQ25101 output (3.7-4.2V). Verify TPS628438 buck converter has correct input. Look for solder bridges on QFN pads with microscope. Measure resistance between VCC and GND — should be more than 1k ohm before power.
No BLE advertising
No BLE advertising
Verify 32MHz crystal is soldered (not just tacked). Check 32.768kHz crystal for RTC. Measure nRF5340 VDDH (should be 3.3V) and VDD (1.0V). Check antenna trace and matching network.
No Wi-Fi scan results
No Wi-Fi scan results
nRF7002 requires its own 40MHz crystal. Check BUCKA/BUCKB rails. Verify SPI connection between nRF5340 and nRF7002. Wi-Fi requires firmware support enabled.
Poor or no audio
Poor or no audio
T5838 microphones are top-port — verify sound inlet faces the enclosure acoustic holes. Check PDM clock (1-3.25MHz) and data lines. Both mics must be in the correct PDM channel (L/R).
Charging doesn't work
Charging doesn't work
Check pogo pin contact resistance (less than 0.5 ohm). Verify FPC connection. Measure charger board USB-C VBUS (5V). Check TPS25200 eFuse output. Verify magnet polarity alignment.