# ESP32-S3 Smart Locker Controller ## Description Welcome to your new project. Imagine what you can build here. ## Project Details - **Owner:** mojahi - **Created:** 3/29/2026 - **Last Updated:** 4/2/2026 - **Visibility:** Public - **System Architecture:** ```mermaid flowchart TD subgraph Power [Power Block] JBARREL[12V Barrel Jack] BUCK[MP2315 12V to 3.3V Buck] CBU[Input and Output Decoupling] end subgraph Controller [Controller Block] USBC[USB-C Connector] ESD[USB Protection and CC] MCU[ESP32-S3-WROOM-1] AUTO[Auto Program Transistors] BTN[Boot and Reset Buttons] end subgraph Periph [Peripheral Block] HX[HX711 Load Cell ADC] JLOAD[LOAD_CELL JST-XH] MOS[MOSFET Lock Driver] JLOCK[12V_LOCK JST-XH] DFLY[Flyback Diode] JKEY[4x4_KEYPAD JST-XH] end JBARREL --> BUCK BUCK --> MCU BUCK --> HX BUCK --> JKEY USBC --> ESD ESD --> MCU AUTO --> MCU BTN --> MCU HX --> JLOAD MCU --> HX MCU --> MOS MOS --> JLOCK DFLY --> JLOCK MCU --> JKEY ``` ## Key Components ### D1 — [SS14](https://www.flux.ai/cherepanyadima/ss14~5b.md) - Role Details: Clamp inductive kick from 12V solenoid lock - Part Type: Diode - Manufacturer Part Number: SS14 - Datasheet URL: https://datasheet.lcsc.com/lcsc/1912111437_Slkor-SLKORMICRO-Elec--SS14_C444721.pdf - Manufacturer Name: Slkor(SLKORMICRO Elec.) - Package: SMA - Role: Flyback Protection - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Anode [pin A] - Cathode [pin C] ### D2 — [SMBJ15A-13-F](https://www.flux.ai/lcsc/smbj15a-13-f~8gof.md) - Role: TVS Protection - Package: SMB - JLCPCB Part Class: Extended Part - Role Details: Unidirectional TVS clamp for 12V input transients after input fuse - Manufacturer Part Number: SMBJ15A-13-F - Manufacturer Name: DIODES(美台) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Diodes-Incorporated-SMBJ15A-13-F_C135046.pdf - Product Info Url: https://lcsc.com/product-detail/TVS_DIODES_SMBJ15A-13-F_SMBJ15A-13-F_C135046.html - Part Type: TVS - Package or Case Code: SMB_L4.6-W3.6-LS5.3-RD - LCSC Part Number: C135046 **Pins:** - A [pin 2] - K [pin 1] ### D3 — [PESD5V0S1BA](https://www.flux.ai/lcsc/pesd5v0s1ba~qi2k.md) - Part Type: ESD Protection Devices - Manufacturer Part Number: PESD5V0S1BA - Package or Case Code: SOD-323_L1.7-W1.3-LS2.5-BI - LCSC Part Number: C2827694 - Manufacturer Name: TECH PUBLIC(台舟) - Role: TVS Protection - Role Details: USB VBUS TVS clamp for 5V sink input protection - Max Reverse Voltage: 5V - Forward Voltage: 0.8V - JLCPCB Part Class: Extended Part - Package: SOD-323 - Diode Type: TVS Diode **Pins:** - 1 [pin 1] - 2 [pin 2] ### F1 — [1812L200/12DR](https://www.flux.ai/jecstronic/1812l20012dr~98l.md) - Datasheet URL: https://www.littelfuse.com/~/media/electronics/datasheets/resettable_ptcs/littelfuse_ptc_1812l_datasheet.pdf.pdf - Current Rating: 2A - Manufacturer Part Number: 1812L150/12DR - Package: 1812 - Part Type: Fuse - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Littelfuse Inc. - Role: Fuse - Role Details: Resettable input fuse on 12V barrel input before TVS and downstream power path **Pins:** - P1 [pin 1] - P2 [pin 2] ### IC1 — [ESP32-S3-WROOM-1-N16R8](https://www.flux.ai/adrian95/esp32-s3-wroom-1-n16r8~fs1.md) - Part Type: Module - Role: MCU - Manufacturer Name: Espressif Systems - Manufacturer Part Number: ESP32-S3-WROOM-1-N16R8 - Package: Module - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.mouser.com/datasheet/2/891/esp32_s3_wroom_1_wroom_1u_datasheet_en-2930317.pdf - Role Details: Main controller with native USB, keypad scan, HX711 interface, and lock control **Pins:** - 3V3 [pin 2] - EN [pin 3] - GND_1 [pin 1] - GND_10 [pin 48] - GND_11 [pin 49] - GND_2 [pin 40] - GND_3 [pin 41] - GND_4 [pin 42] - GND_5 [pin 43] - GND_6 [pin 44] - GND_7 [pin 45] - GND_8 [pin 46] - GND_9 [pin 47] - IO0 [pin 27] - IO1 [pin 39] - IO10 [pin 18] - IO11 [pin 19] - IO12 [pin 20] - IO13 [pin 21] - IO14 [pin 22] - IO15 [pin 8] - IO16 [pin 9] - IO17 [pin 10] - IO18 [pin 11] - IO19 [pin 13] - IO2 [pin 38] - IO20 [pin 14] - IO21 [pin 23] - IO3 [pin 15] - IO35 [pin 28] - IO36 [pin 29] - IO37 [pin 30] - IO38 [pin 31] - IO39 [pin 32] - IO4 [pin 4] - IO40 [pin 33] - IO41 [pin 34] - IO42 [pin 35] - IO45 [pin 26] - IO46 [pin 16] - IO47 [pin 24] - IO48 [pin 25] - IO5 [pin 5] - IO6 [pin 6] - IO7 [pin 7] - IO8 [pin 12] - IO9 [pin 17] - RXD0 [pin 36] - TXD0 [pin 37] ### J1 — [USB-C 2.0 Receptacle](https://www.flux.ai/corynrobinson/usb-c-20-receptacle~cf.md) - Role: USB Connector - Purchase Url: https://www.digikey.com/en/products/detail/gct/USB4105-GF-A/11198441 - Package: USB-C Receptacle - Role Details: Native USB programming/debug connector for ESP32-S3 - Manufacturer Part Number: USB4105-GF-A - Datasheet URL: https://gct.co/files/drawings/usb4105.pdf - Part Type: USB C - Manufacturer Name: GTC **Pins:** - CC1 [pin 6] - CC2 [pin 12] - D- [pin 9] - D- [pin 7] - D+ [pin 10] - D+ [pin 8] - GND [pin 15] - GND [pin 1] - GND [pin 16] - GND [pin 2] - SBU1 [pin 11] - SBU2 [pin 5] - VBUS [pin 14] - VBUS [pin 13] - VBUS [pin 4] - VBUS [pin 3] ### J2 — [B2B-XH-A(LF)(SN)](https://www.flux.ai/adrian95/b2b-xh-alfsn~5xx.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Connector - Manufacturer Part Number: B2B-XH-A(LF)(SN) - Role Details: 12V solenoid lock connector, pin 1 = +12V, pin 2 = low-side switched return - Part Type: Connector - Manufacturer Name: JST Sales America Inc. - Package: THT 2.50mm - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/eXH.pdf **Pins:** - P1 [pin 1] - P2 [pin 2] ### J3 — [B4B-XH-A(LF)(SN)](https://www.flux.ai/adrian95/b4b-xh-alfsn~8ne.md) - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/eXH.pdf - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: JST Sales America Inc. - Manufacturer Part Number: B4B-XH-A(LF)(SN) - Role Details: Load-cell connector, pin 1 = A+, pin 2 = A-, pin 3 = E+, pin 4 = E- - Part Type: Connector - Package: THT 2.50mm **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### J4 — [B8B-XH-A(LF)(SN)](https://www.flux.ai/adrian95/b8b-xh-alfsn~8f6.md) - Part Type: Connector - Package: THT 2.50mm - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/eXH.pdf - Manufacturer Name: JST Sales America Inc. - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Keypad connector, pins 1-4 = rows, pins 5-8 = columns - Manufacturer Part Number: B8B-XH-A(LF)(SN) **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] - 8 [pin 8] ### Q1 — [AO3400A](https://www.flux.ai/adrian95/ao3400a~ug9.md) - Role Details: Low-side MOSFET switch for 12V solenoid lock - Part Type: Transistor - Manufacturer Part Number: AO3400A - Manufacturer Name: Alpha & Omega Semiconductor Inc. - Role: Lock Driver - Package: SOT-23 - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/Alpha%20&%20Omega/AO3400A_ds.pdf **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q2 — [BC817-16W-7](https://www.flux.ai/jecstronic/bc817-16w-7~ind.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: SOT-23-3 - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds30575.pdf - Part Type: Transistor - Role: Auto Program - Manufacturer Part Number: BC817-16W-7 - Role Details: NPN transistor used in ESP32 auto-program/reset circuit - Manufacturer Name: Diodes Incorporated **Pins:** - B [pin 1] - C [pin 3] - E [pin 2] ### Q3 — [BC817-16W-7](https://www.flux.ai/jecstronic/bc817-16w-7~ind.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Auto Program - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds30575.pdf - Role Details: NPN transistor used in ESP32 auto-program/reset circuit - Package: SOT-23-3 - Part Type: Transistor - Manufacturer Name: Diodes Incorporated - Manufacturer Part Number: BC817-16W-7 **Pins:** - B [pin 1] - C [pin 3] - E [pin 2] ### SW1 — [SW_Push](https://www.flux.ai/adrian95/swpush~f5x.md) - Part Type: Switch - Manufacturer Name: Schurter Inc. - Manufacturer Part Number: 1301.9314 - Role Details: BOOT button, pulls ESP32 GPIO0 low for download mode - Package: SMD Tactile - Datasheet URL: https://us.schurter.com/en/datasheet/typ_6x6_mm_tact_switches.pdf - Role: Button **Pins:** - 1 - 2 ### SW2 — [SW_Push](https://www.flux.ai/adrian95/swpush~f5x.md) - Part Type: Switch - Role: Button - Manufacturer Part Number: 1301.9314 - Manufacturer Name: Schurter Inc. - Datasheet URL: https://us.schurter.com/en/datasheet/typ_6x6_mm_tact_switches.pdf - Role Details: RESET button, pulls ESP32 EN low for reset - Package: SMD Tactile **Pins:** - 1 - 2 ### U1 — [MP2315SGJ-Z](https://www.flux.ai/support/mp2315sgj-z~y8.md) - Product Info Url: https://www.monolithicpower.com/en/catalog/product/view/id/1078?utm_source=ultralibrarian&utm_medium=component_search&utm_campaign=listing - Manufacturer Name: Monolithic Power Systems - Datasheet URL: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP2315S - Role Details: Main 12V to 3.3V regulator for controller and peripherals - Package: TSOT23-8 - Manufacturer Part Number: MP2315SGJ-Z - Package or Case Code: TSOT23-8_MP2315S_MNP - Role: Buck Regulator - Product Image Url: https://www.monolithicpower.com/pub/media/catalog/product/M/P/MP2315S_1078_1.jpg **Pins:** - AAM [pin 1] - BST [pin 5] - EN [pin 6] - FB [pin 8] - GND [pin 4] - IN [pin 2] - SW [pin 3] - VCC [pin 7] ### U2 — [HX711](https://www.flux.ai/kicad-part-library/hx711~na6.md) - Package: SOP-16 - Datasheet URL: https://web.archive.org/web/20220615044707/https://akizukidenshi.com/download/ds/avia/hx711.pdf - Role Details: Bridge sensor ADC for load-cell measurement - Role: Load Cell ADC - Package or Case Code: SOP-16_3.9x9.9mm_P1.27mm - Manufacturer Part Number: HX711 **Pins:** - AGND [pin 5] - AVDD [pin 3] - BASE [pin 2] - DOUT [pin 12] - DVDD [pin 16] - INA- [pin 7] - INA+ [pin 8] - INB- [pin 9] - INB+ [pin 10] - PD_SCK [pin 11] - RATE [pin 15] - VBG [pin 6] - VFB [pin 4] - VSUP [pin 1] - XI [pin 14] - XO [pin 13] ### U3 — [IP4234CZ6](https://www.flux.ai/kicad-part-library/ip4234cz6~2q.md) - Manufacturer Part Number: IP4234CZ6 - Package: SC-74-6 - Package or Case Code: SC-74-6_1.55x2.9mm_P0.95mm - Role Details: Low-capacitance USB data-line ESD protection for ESP32-S3 native USB; one spare channel intentionally left unused - Role: ESD Protection - Datasheet URL: https://assets.nexperia.com/documents/data-sheet/IP4234CZ6.pdf - Manufacturer Name: Texas Instruments Inc. **Pins:** - 4 [pin 4] - 6 [pin 6] - 3 [pin 3] - 1 [pin 1] - VN [pin 2] - VP [pin 5] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/mojahi/esp32-s3-smart-locker-controller~cr](https://www.flux.ai/mojahi/esp32-s3-smart-locker-controller~cr).* --- *Generated from [https://www.flux.ai/mojahi/esp32-s3-smart-locker-controller~cr](https://www.flux.ai/mojahi/esp32-s3-smart-locker-controller~cr)*