MotionSense IMU is a custom 2-layer PCB built around the ST LSM6DSM 6-axis accelerometer and gyroscope.
The board takes 5 V from USB-C, regulates it to 3.3 V, and breaks out the IMU's I2C interface and interrupt signal through a 5-pin header.
- LSM6DSM 6-axis accelerometer + gyroscope
- AP2112K-3.3 LDO regulator
- USB-C 5 V input
- 4.7 kΩ pull-up resistors on SDA and SCL
- Decoupling capacitors for the regulator and IMU
- 5-pin interface header
- 2-layer PCB
- Board size: approximately 35 mm × 27 mm
| Pin | Signal |
|---|---|
| 1 | 3V3 |
| 2 | GND |
| 3 | SDA |
| 4 | SCL |
| 5 | INT1 |
The schematic and PCB were designed in KiCad.
During routing, I experimented with Quilter and Freerouting before bringing the design back into KiCad for final cleanup and verification.
The final design passes KiCad DRC with:
- 0 violations
- 0 unconnected items
Gerber and drill files were generated and inspected before manufacturing.
The schematic includes the USB-C power input, AP2112K 3.3 V regulator, LSM6DSM IMU, I2C pull-up resistors, decoupling capacitors, and J2 breakout header.
The editable KiCad schematic is available in MotionSense_IMU.kicad_sch.
The board is a 2-layer design with USB-C power input on one side and the I2C breakout header on the opposite side.
Rev 1 was submitted to JLCPCB for fabrication and assembly in August 2026.
Five PCBs were ordered, with two boards receiving component assembly.
The 1×5 J2 header is intentionally left unpopulated and will be soldered manually during bring-up.
MotionSense_IMU.kicad_pcb— KiCad PCB layoutMotionSense_IMU.kicad_pro— KiCad projectMotionSense_IMU.kicad_sch— KiCad schematicBOM.csv— bill of materialsMotionSense_IMU_Rev1_Gerbers.zip— Gerber and drill filespcb_3D.png— 3D board renderpcb_layout.png— PCB layout imageschematic.png— schematic image
The Rev 1 Gerber and drill files used for manufacturing are included in the repository.
Rev 1 has been ordered for fabrication and assembly.
The PCB design and manufacturing files are complete. The next stage is hardware bring-up and firmware validation once the assembled boards arrive.
- Inspect the assembled board for soldering or placement issues.
- Solder the J2 header.
- Check for shorts between 3.3 V and GND.
- Power the board through USB-C.
- Verify the 5 V input and 3.3 V regulator output with a multimeter.
- Connect an ESP32 to SDA, SCL, and GND.
- Detect the LSM6DSM over I2C.
- Read the
WHO_AM_Iregister to confirm communication. - Read live accelerometer and gyroscope data.
- Test the INT1 interrupt output.
- Prepare ESP32 bring-up firmware
- Complete electrical testing
- Validate accelerometer and gyroscope measurements
- Test interrupt functionality
- Document test results
- Record any changes needed for Rev 2
The goal of this project is to work through the complete PCB development process, from schematic capture and component selection through layout, manufacturing, assembly, and hardware validation.