Si4
About the Si4 PCB
Si4 is an open source ESP32 PCB design by aliadnani, published on GitHub. It is a 4-layer board measuring 78 × 99 mm, with 57 components from 30 distinct parts.
Its main chip is the ESP32-S3-WROOM-1, from the ESP32 family. Other key parts include the IP5306_CK (BMS), TLV62569DBV (BMS Step Down), AS5600 (Encoder), MCP23017_SS and STSPIN233. By type, the board carries 17 capacitors, 13 resistors, 7 switches, 6 ICs, 6 diodes and 5 connectors.
Main components on the Si4
Si4 bill of materials (BOM)
57 components, 30 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | IP5306_CK (BMS) | SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm | U1 |
| 1 | TLV62569DBV (BMS Step Down) | SOT-23-5 | U2 |
| 1 | ESP32-S3-WROOM-1 | ESP32-S3-WROOM-1 | U3 |
| 1 | AS5600 (Encoder) | SOIC-8_3.9x4.9mm_P1.27mm | U4 |
| 1 | MCP23017_SS | SSOP-28_5.3x10.2mm_P0.65mm | U5 |
| 1 | STSPIN233 | VQFN-16-1EP_3x3mm_P0.5mm_EP1.8x1.8mm | U6 |
| 1 | SPI OLED Display | PinSocket_1x07_P2.54mm_Vertical | J1 |
| 1 | USB-C Connector | USB_C_Receptacle_XKB_U262-16XN-4BVC11 | J2 |
| 1 | Audio Hat I2S/I2C | PinSocket_1x10_P1.27mm_Vertical | J3 |
| 1 | Audio Hat Power | PinSocket_1x08_P1.27mm_Vertical | J4 |
| 1 | BLDC Gimbal Motor | SolderWire-0.75sqmm_1x03_P7mm_D1.25mm_OD3.5mm | J5 |
| 1 | 18650 | SolderWire-0.75sqmm_1x02_P7mm_D1.25mm_OD3.5mm | BT1 |
| 1 | SW_Push | SW_SPST_TS-1088-xR020 | SW1 |
| 5 | SW_Push | SW_Hotswap_Kailh_MX | SW2, SW3, SW4, SW5, SW7 |
| 1 | SW_SPDT_MSM | MTS-103 Switch | SW6 |
| 6 | LED | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1, D2, D3, D4, D5, D6 |
| 1 | 1 uH | L_Taiyo-Yuden_NR-40xx_HandSoldering | L1 |
| 1 | 2.2 uH | L_Taiyo-Yuden_NR-40xx_HandSoldering | L2 |
| 5 | 22 uF | C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C1, C2, C5, C7, C15 |
| 6 | 10 uF | C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C3, C4, C6, C10, C11, C12 |
Show 10 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | 1 uF | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C8, C9, C13 |
| 1 | 2.2 uF | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C14 |
| 2 | 10 nF | C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C16, C17 |
| 2 | 2R | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2 |
| 1 | 453K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R3 |
| 2 | 5.1 K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4, R6 |
| 3 | 10 K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R5, R8, R11 |
| 1 | 100K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R7 |
| 2 | 4.7 K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R9, R10 |
| 2 | 1k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R12, R13 |
Si4 design files
The KiCad project lives in the aliadnani/si4 repository on GitHub; these links point at the commit this page was built from.
- Layouthardware/si4/si4.kicad_pcb
- Schematichardware/si4/si4.kicad_sch
Si4: common questions
What microcontroller does the Si4 use?
The Si4 is built around the ESP32-S3-WROOM-1, from the ESP32 family.
How big is the Si4 PCB?
The Si4 measures 78 × 99 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the Si4?
57 components, from 30 distinct parts. The full bill of materials is listed on this page.
Where can I download the Si4 design files?
From the aliadnani/si4 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Si4 design in my own project?
The repository has no license, so all rights stay with aliadnani. Use it as a reference, and ask the author before reusing the design.
Can I test firmware for the Si4 without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.
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