# RAKSHAK Railway Crossing Safety System ## Description STM32F401 Blackpill-style railway crossing safety controller with dual 12V input selection, LM2596 5V buck, AMS1117-3.3 MCU rail, horn relay driver, and edge-mounted off-board sensor, servo, and UART connectors for modular prototyping. ## Project Details - **Owner:** ompatil13 - **Created:** 4/7/2026 - **Last Updated:** 4/7/2026 - **Visibility:** Public ## Key Components ### D1 — [SS14FP](https://www.flux.ai/lcsc/ss14fp.md) - Role Details: Series Schottky diode protecting the selected 12V input rail - Package or Case Code: POWERDI-123_L2.8-W1.8-LS3.7-RD-1 - Manufacturer Part Number: SS14FP - JLCPCB Part Class: Extended Part - Package: POWERDI-123 - Role: Reverse polarity diode - LCSC Part Number: C894423 - Manufacturer Name: onsemi(安森美) **Pins:** - A [pin 2] - K [pin 1] ### D2 — [1N4007](https://www.flux.ai/adrian95/1n4007.md) - Manufacturer Part Number: 1N4007 - Package: DO-41 - Role: Relay flyback diode - Manufacturer Name: Yangjie Technology - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://diotec.com/tl_files/diotec/files/pdf/datasheets/1n4001.pdf - Role Details: Flyback clamp across horn relay coil - Part Type: Diode **Pins:** - anode [pin 2] - cathode [pin 1] ### J1 — [Barrel_Jack_Switch_SMT_FC681465S](https://www.flux.ai/jecstronic/barreljackswitchsmtfc681465s.md) - Manufacturer Name: CLIFF Electronic Components Ltd - Role: Primary DC input - Manufacturer Part Number: FC681465S - Role Details: 2.1mm barrel jack for external 12V adapter input - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Datasheet URL: https://www.cliffuk.co.uk/products/dcconnectors/DualDCSockets.pdf - Package: Barrel jack **Pins:** - 1 [pin 4] - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J10 — [FTSH-103-01-L-D](https://www.flux.ai/adrian95/ftsh-103-01-l-d.md) - Part Type: Connector - Package: 2x3 1.27mm TH - Role Details: 2x3 ARM SWD header for programming and debug access - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: FTSH-103-01-L-D - Manufacturer Name: Samtec - Implementation Details: Pin 1=VTref 3.3V, Pin 3=NRST, Pins 4 and 5=GND, Pin 6=SWO; SWDIO and SWCLK require confirmation against the Blackpill module symbol - Datasheet URL: https://suddendocs.samtec.com/catalog_english/ftsh_th.pdf - Role: SWD debug connector **Pins:** - 01 [pin 01] - 02 [pin 02] - 03 [pin 03] - 04 [pin 04] - 05 [pin 05] - 06 [pin 06] ### J2 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 61300311021 - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=Ultrasonic sensor signal - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P - Manufacturer Name: Wurth Elektronik - Role Details: HC-SR04 sensor header 1 with GND, 5V, signal pair support - Part Type: Connector - Role: Ultrasonic sensor connector - Package: 1x3 2.54mm TH **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J3 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf - Manufacturer Part Number: 61300311021 - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=Ultrasonic sensor signal - Package: 1x3 2.54mm TH - Role: Ultrasonic sensor connector - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: HC-SR04 sensor header 2 with GND, 5V, signal pair support - Part Type: Connector - Manufacturer Name: Wurth Elektronik - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J4 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Microwave sensor connector - Manufacturer Part Number: 61300311021 - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf - Role Details: HB100 radar sensor header 1 with GND, 5V, signal - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P - Manufacturer Name: Wurth Elektronik - Package: 1x3 2.54mm TH - Part Type: Connector - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=Microwave sensor output **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J5 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf - Role Details: HB100 radar sensor header 2 with GND, 5V, signal - Manufacturer Part Number: 61300311021 - Package: 1x3 2.54mm TH - License: https://creativecommons.org/licenses/by/4.0/ - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=Microwave sensor output - Role: Microwave sensor connector - Part Type: Connector - Manufacturer Name: Wurth Elektronik - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J6 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=IR sensor output - Manufacturer Name: Wurth Elektronik - Part Type: Connector - Package: 1x3 2.54mm TH - Role Details: IR sensor header 1 with GND, 5V, signal - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 61300311021 - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf - Role: IR sensor connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J7 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - Role Details: IR sensor header 2 with GND, 5V, signal - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P - Manufacturer Name: Wurth Elektronik - Part Type: Connector - Role: IR sensor connector - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=IR sensor output - License: https://creativecommons.org/licenses/by/4.0/ - Package: 1x3 2.54mm TH - Manufacturer Part Number: 61300311021 - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J8 — [61300311021](https://www.flux.ai/adrian95/61300311021.md) - Manufacturer Part Number: 61300311021 - Role Details: Servo header with GND, 5V, PWM control - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300311021.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Role: Servo connector - Part Type: Connector - Package: 1x3 2.54mm TH - Package or Case Code: HDRRA3W79P0X254_1X3_762X254X269P - Manufacturer Name: Wurth Elektronik - Implementation Details: Pin 1=GND, Pin 2=5V, Pin 3=Servo PWM control **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### J9 — [PCC03SAAN](https://www.flux.ai/adrian95/pcc03saan.md) - Manufacturer Name: Sullins - Role Details: Pin order GND, TX out from board, RX into board - Package or Case Code: HDRV3W64P0X254_1X3_762X254X838P - Datasheet URL: https://s3.amazonaws.com/catalogspreads-pdf/PAGE112-113%20.100%20MALE%20HDR.pdf - Role: UART debug connector - Manufacturer Part Number: PCC03SAAN - Implementation Details: Pin 1=GND, Pin 2=Board TX, Pin 3=Board RX - Part Type: HDRV3W64P0X254_1X3_762X254X838P - Package: 1x3 2.54mm TH **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### K1 — [SRD-05VDC-SL-C](https://www.flux.ai/jecstronic/srd-05vdc-sl-c.md) - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://datasheet.lcsc.com/lcsc/1811021933_Ningbo-Songle-Relay-SRD-05VDC-SL-C_C35449.pdf - Manufacturer Part Number: SRD-05VDC-SL-C - Part Type: Relay - Role Details: 5V coil SPDT relay switching horn supply - Manufacturer Name: Ningbo Songle Relay - Role: Horn relay - Package: Relay THT **Pins:** - A1 [pin A1] - A2 [pin A2] - COM [pin COM] - NC [pin NC] - NO [pin NO] ### PS1 — [LM2596 DC-DC buck converter](https://www.flux.ai/vasy_skral/lm2596-dc-dc-buck-converter.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: 5V regulator - Package: Buck module - Part Type: Integrated Circuit - Role Details: LM2596 buck module generating 5V from protected 12V input **Pins:** - IN - [pin 2] - IN + [pin 1] - OUT - [pin 3] - OUT + [pin 4] ### Q1 — [2N2222A](https://www.flux.ai/lcsc/2n2222a.md) - Frequency: 250MHz - Compliance: RoHS - Manufacturer Part Number: 2N2222A - Role: Relay driver transistor - LCSC Part Number: C118536 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1809200018_ST-Semtech-2N2222A_C118536.pdf - Manufacturer Name: ST(先科) - Product Info Url: https://lcsc.com/product-detail/Transistors-NPN-PNP_2N2222_C118536.html - JLCPCB Part Class: Extended Part - Package: TO-92-3 - Package or Case Code: TO-92-3_L4.9-W3.7-P1.27-L - Part Type: Transistors/Thyristors/Bipolar (BJT) - Role Details: NPN transistor driving 5V relay coil from STM32 GPIO - Transistor Type: NPN **Pins:** - B [pin 2] - C [pin 3] - E [pin 1] ### SW1 — [SS-12D07-VG 4 NS GA PA](https://www.flux.ai/adrian95/ss-12d07-vg-4-ns-ga-pa.md) - Role Details: SPDT manual switch selecting one of two 12V sources - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Switch - Package: SPDT slide switch - Datasheet URL: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/580/SS-12D07-VG_GA_PA.pdf - Manufacturer Part Number: SS12D07VG4NSGAPA - Role: Input source select - Manufacturer Name: C&K **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### U1 — [STM32F401CCU6](https://www.flux.ai/karolrojas/stm32f401ccu6.md) - Role Details: STM32F401 Blackpill-style carrier footprint operating from 3.3V with fixed header pin mapping - Datasheet URL: https://www.st.com/en/microcontrollers-microprocessors/stm32f411ce.html - Manufacturer Part Number: STM32 Black Pill - Manufacturer Name: ST-Microelectronics - Part Type: Breakout board - Package: Blackpill module - Role: Main MCU module **Pins:** - 3V3 - 3V3 - 5V - 5V - GND - GND - NRST - P37 - PA0 - PA1 - PA10 - PA11 - PA12 - PA15 - PA3 - PA4 - PA5 - PA6 - PA7 - PA8 - PA9 - PB0 - PB1 - PB10 - PB12 [pin 1] - PB13 - PB14 - PB15 - PB2 - PB3 - PB4 - PB5 - PB6 - PB7 - PB8 - PB9 - PC13 - PC14 - PC15 - VBAT ### U2 — [AMS1117-3.3](https://www.flux.ai/vasy_skral/ams1117-33.md) - Role Details: AMS1117 fixed 3.3V LDO from 5V rail for STM32 module - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: http://www.advanced-monolithic.com/pdf/ds1117.pdf - Role: 3.3V regulator - Manufacturer Part Number: AMS1117-3.3 - Manufacturer Name: AMS - Symbol Style: Parametric - Package: SOT-223 - Part Type: Integrated Circuit **Pins:** - GND [pin 1] - TAB(VOUT) [pin 4] - VIN [pin 3] - VOUT [pin 2] ### U3 — [KF128-5.08-2P-AA](https://www.flux.ai/lcsc/kf128-5p08-2p-aa.md) - Part Type: Screw terminal - Operating Temperature: -40℃~+105℃ - Package or Case Code: CONN-TH_P5.08_KF128-5.08-2P - Role: 12V input terminal - Role Details: Alternate 12V screw terminal input - Connector Type: Screw terminal - Product Info Url: https://lcsc.com/product-detail/New-Quadratic-Unclassified-Data_Cixi-Kefa-Elec-KF128-5-08-2P_C474952.html - Connector Gender: Female - Connector Positions: 2 - Manufacturer Part Number: KF128-5.08-2P-AA - Manufacturer Name: KEFA(科发) - Connector Rows: 1 - Current Rating: 24A - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2408211511_Cixi-Kefa-Elec-KF128-5-08-2P-AA_C474952.pdf - Connector Pitch: 5.08mm - LCSC Part Number: C474952 - JLCPCB Part Class: Extended Part - Package: 5.08mm terminal block **Pins:** - 1 [pin 1] - 2 [pin 2] ### U4 — [KF128-5.08-2P-AA](https://www.flux.ai/lcsc/kf128-5p08-2p-aa.md) - Operating Temperature: -40℃~+105℃ - Role Details: 2-pin screw terminal for horn load connection - Part Type: Screw terminal - Package or Case Code: CONN-TH_P5.08_KF128-5.08-2P - Role: Horn connector - Package: 5.08mm terminal block - Connector Type: Screw terminal - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2408211511_Cixi-Kefa-Elec-KF128-5-08-2P-AA_C474952.pdf - Current Rating: 24A - Connector Rows: 1 - Manufacturer Part Number: KF128-5.08-2P-AA - Manufacturer Name: KEFA(科发) - Connector Positions: 2 - Product Info Url: https://lcsc.com/product-detail/New-Quadratic-Unclassified-Data_Cixi-Kefa-Elec-KF128-5-08-2P_C474952.html - Connector Gender: Female - Connector Pitch: 5.08mm - LCSC Part Number: C474952 - JLCPCB Part Class: Extended Part **Pins:** - 1 [pin 1] - 2 [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/ompatil13/rakshak-railway-crossing-safety-system](https://www.flux.ai/ompatil13/rakshak-railway-crossing-safety-system).* --- *Generated from [https://www.flux.ai/ompatil13/rakshak-railway-crossing-safety-system](https://www.flux.ai/ompatil13/rakshak-railway-crossing-safety-system)*