Semafor bottom
About the Semafor bottom PCB
Semafor bottom is an open source ESP32 PCB design by renata7zemanova, published on GitHub. It is a 2-layer board measuring 99.9 × 100 mm, with 76 components from 38 distinct parts.
Its main chip is the ESP32-C3, from the ESP32 family. Other key parts include the CN3058E, LT1930, E22-900T22D, AT42QT1070-S and PCA9536D. By type, the board carries 27 resistors, 14 capacitors, 11 diodes, 8 connectors, 6 ICs and 5 transistors.
Main components on the Semafor bottom
Semafor bottom bill of materials (BOM)
76 components, 38 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | ESP32-C3 | ESP32-C3 | U1 |
| 1 | CN3058E | SOP-8_3.76x4.96mm_P1.27mm | U2 |
| 1 | LT1930 | SOT-23-5 | U3 |
| 1 | E22-900T22D | E22-900T22D | U4 |
| 1 | AT42QT1070-S | SOIC-14_3.9x8.7mm_P1.27mm | U5 |
| 1 | PCA9536D | SOIC-8_3.9x4.9mm_P1.27mm | U6 |
| 1 | Motor_DC | PinHeader_1x02_P2.54mm_Vertical | M1 |
| 2 | Q_PMOS_GSD | SOT-23 | Q2, Q7 |
| 3 | Q_NMOS_GSD | SOT-23 | Q3, Q4, Q6 |
| 1 | USB_C_Receptacle_USB2.0 | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
| 1 | Conn_01x02_Female | PinSocket_1x02_P1.27mm_Vertical | J2 |
| 3 | Conn_01x03_Male | PinSocket_1x03_P2.54mm_Vertical | J3, J4, J13 |
| 1 | Conn_01x06_Female | PinSocket_1x06_P2.54mm_Vertical | J8 |
| 2 | Conn_01x04_Female | PinHeader_1x04_P2.54mm_Vertical | J9, J11 |
| 1 | Battery_Cell | battery_dock | BT1 |
| 1 | Buzzer | PIEZO | BZ1 |
| 1 | SW_SPDT | BTN_1101M2S2AV2QE2 | SW1 |
| 3 | Green | LED_0603_1608Metric | D13, D15, D16 |
| 1 | Red | LED_0603_1608Metric | D14 |
| 1 | MBR0520 | D_SOD-123 | D17 |
Show 18 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | SD05_SOD323 | D_SOD-323 | D18, D19, D20 |
| 3 | D_Schottky | D_SOD-123 | D21, D22, D24 |
| 1 | 4u7 | L_CDRH3D18 | L1 |
| 3 | 4u7 | C_0805_2012Metric | C1, C10, C13 |
| 1 | 1u | C_0805_2012Metric | C2 |
| 1 | 100u | C_0805_2012Metric | C3 |
| 5 | 100n | C_0603_1608Metric | C4, C6, C9, C25, C26 |
| 4 | 10u | C_0805_2012Metric | C5, C7, C8, C14 |
| 1 | 47k | R_0603_1608Metric | R1 |
| 2 | 5k1 | R_0402_1005Metric | R2, R3 |
| 12 | 10k | R_0603_1608Metric | R5, R7, R11, R16, R17, R18, R19, R20 +4 |
| 3 | 1k | R_0603_1608Metric | R6, R12, R29 |
| 1 | 1k2 | R_0603_1608Metric | R8 |
| 1 | 39k | R_0603_1608Metric | R9 |
| 1 | 13k | R_0603_1608Metric | R10 |
| 1 | 150k | R_0603_1608Metric | R13 |
| 4 | 100k | R_0603_1608Metric | R14, R15, R24, R25 |
| 1 | 180R | R_0603_1608Metric | R28 |
Semafor bottom design files
The KiCad project lives in the renata7zemanova/Semafor repository on GitHub; these links point at the commit this page was built from.
Semafor bottom: common questions
What microcontroller does the Semafor bottom use?
The Semafor bottom is built around the ESP32-C3, from the ESP32 family.
How big is the Semafor bottom PCB?
The Semafor bottom measures 99.9 × 100 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Semafor bottom?
76 components, from 38 distinct parts. The full bill of materials is listed on this page.
Where can I download the Semafor bottom design files?
From the renata7zemanova/Semafor repository on GitHub, which has the KiCad layout; the links under Design files point to each one.
Can I use the Semafor bottom design in my own project?
The repository has no license, so all rights stay with renata7zemanova. Use it as a reference, and ask the author before reusing the design.
Can I test firmware for the Semafor bottom 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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