# GPS Dual Relay Switch ## Description 12–24 VDC GPS-fix-controlled dual relay board. Relays switch immediately based on valid GPS fix status and provide SPDT contacts for 12/24 V loads up to 3 A with external GPS antenna support. ## Project Details - **Owner:** alexb123 - **Created:** 7/8/2026 - **Last Updated:** 7/28/2026 - **Visibility:** Public - **Stars:** 1 ## Key Components ### 12/24v to 5vdc — [DC-DC Multi-output Buck Converter (3.3V/5V/9V/12V)](https://www.flux.ai/adrian95/dc-dc-multi-output-buck-converter-3p3v5v9v12v~jee.md) - Manufacturer Part Number: DFR1015 - Manufacturer Name: DFRobot - Role Details: 7.5–30V input buck module set to 5V output for Pico, GPS header, and relay coils - Role: Voltage Regulator - Part Type: Buck Converter - License: https://creativecommons.org/licenses/by/4.0/ - Purchase Url: https://www.dfrobot.com/product-2599.html **Pins:** - - IN - - IN - - OUT - - OUT - + IN - + IN - + OUT - + OUT ### Battery — [BAT-HLD-001](https://www.flux.ai/vasy_skral/bat-hld-001~h0.md) - Datasheet URL: https://linxtechnologies.com/wp/wp-content/uploads/battery_holder_overview_guide.pdf - Part Type: Connector - Manufacturer Name: Linx Technologies Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: BAT-HLD-001 **Pins:** - NEG [pin N1] - POS [pin P2] - POS [pin P1] ### D1 — [SMBJ24A-TR](https://www.flux.ai/lcsc/smbj24a-tr~hqz2.md) - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/TVS_STMicroelectronics_SMBJ24A-TR_SMBJ24A-TR_C133668.html - LCSC Part Number: C133668 - Part Type: TVS - Manufacturer Name: ST(意法半导体) - Manufacturer Part Number: SMBJ24A-TR - Package or Case Code: SMB_L4.6-W3.6-LS5.3-RD - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_STMicroelectronics-SMBJ24A-TR_C133668.pdf **Pins:** - A [pin 2] - K [pin 1] ### D2 — [1N5819HW-7-F](https://www.flux.ai/jecstronic/1n5819hw-7-f~x5v.md) - Part Type: Diode - Manufacturer Name: Diodes Incorporated - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds30217.pdf - Role Details: Schottky clamp across K1 coil, cathode to 5V - Manufacturer Part Number: 1N5819HW-7-F - Role: Flyback Diode - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - A [pin 2] - K [pin 1] ### D3 — [1N5819HW-7-F](https://www.flux.ai/jecstronic/1n5819hw-7-f~x5v.md) - Role: Flyback Diode - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds30217.pdf - Manufacturer Name: Diodes Incorporated - Part Type: Diode - Role Details: Schottky clamp across K2 coil, cathode to 5V - Manufacturer Part Number: 1N5819HW-7-F - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - A [pin 2] - K [pin 1] ### F1 Fuse — [MF-R050](https://www.flux.ai/lcsc/mf-r050~foz9.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409291503_BOURNS-MF-R050_C208476.pdf - JLCPCB Part Class: Extended Part - Role: Protection - Manufacturer Part Number: MF-R050 - Part Type: Resettable Fuses - LCSC Part Number: C208476 - Role Details: 500mA hold PTC on VIN input; logic/relay peak estimated under 0.45A at 5V - Manufacturer Name: BOURNS - Product Info Url: https://lcsc.com/product-detail/PTC-Fuse_BOURNS_MF-R050_BOURNS-MF-R050_C208476.html - Package or Case Code: FUSE-TH_L9.0-W3.0-P5.10-D0.6-S1.10 **Pins:** - 1 [pin 1] - 2 [pin 2] ### GPS Receiver — [NEO-F10N-00B](https://www.flux.ai/adrian95/neo-f10n-00b~hhz.md) - Package or Case Code: NEOF10N00B - Datasheet URL: https://content.u-blox.com/sites/default/files/documents/NEO-F10N_DataSheet_UBX-23002117.pdf - Manufacturer Part Number: NEO-F10N-00B - Part Type: Integrated Circuit - Integrated Circuit Type: RF Device - Manufacturer Name: u-blox - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - EXTINT [pin 4] - GND_1 [pin 10] - GND_2 [pin 12] - GND_3 [pin 13] - GND_4 [pin 24] - LNA_EN [pin 14] - RESERVED_1 [pin 2] - RESERVED_2 [pin 5] - RESERVED_3 [pin 6] - RESERVED_4 [pin 7] - RESERVED_5 [pin 15] - RESERVED_6 [pin 16] - RESERVED_7 [pin 17] - RESERVED_8 [pin 18] - RESERVED_9 [pin 19] - RESET_N [pin 8] - RF_IN [pin 11] - RXD [pin 21] - SAFEBOOT_N [pin 1] - TIMEPULSE [pin 3] - TXD [pin 20] - V_BCKP [pin 22] - VCC [pin 23] - VCC_RF [pin 9] ### J1 — [XY301V-A-5.0-2P](https://www.flux.ai/jharwinbarrozo/xy301v-a-50-2p~u6.md) - Manufacturer Name: Ningbo Xinlaiya Elec. - Part Type: Connector - Manufacturer Part Number: XY301V-A-5.0-2P - Datasheet URL: https://www.lcsc.com/datasheet/C557651.pdf?spm=wm.sxq.inf.ggs&lcsc_vid=E1BYV1AHFgUMXgFVQ1AMU1JVQFReXgIATwJfA10DFVkxVlNRT1dXXlVTQ1hbUjsOAxUeFF5JWBYZEEoBGA4JCwFIFA4DSA%3D%3D - Role Details: 12–24 VDC input, rated 15A/300V terminal block - Role: Power Input **Pins:** - PIN1 [pin 1] - PIN2 [pin 2] ### J3 — [XY301V-A-5.0-3P](https://www.flux.ai/jharwinbarrozo/xy301v-a-50-3p~ox.md) - Manufacturer Part Number: XY301V-A-5.0-3P - Datasheet URL: https://www.lcsc.com/datasheet/lcsc_datasheet_2411121455_Ningbo-Xinlaiya-Elec--XY301V-A-5-0-3P_C557652.pdf - Role Details: Relay 1 isolated contact terminal for 12/24VDC 3A load - Manufacturer Name: Ningbo Xinlaiya Elec. - Role: Load Terminal **Pins:** - PIN1 [pin 1] - PIN2 [pin 2] - PIN3 [pin 3] ### J4 — [XY301V-A-5.0-3P](https://www.flux.ai/jharwinbarrozo/xy301v-a-50-3p~ox.md) - Manufacturer Part Number: XY301V-A-5.0-3P - Datasheet URL: https://www.lcsc.com/datasheet/lcsc_datasheet_2411121455_Ningbo-Xinlaiya-Elec--XY301V-A-5-0-3P_C557652.pdf - Manufacturer Name: Ningbo Xinlaiya Elec. - Role Details: Relay 2 isolated contact terminal for 12/24VDC 3A load - Role: Load Terminal **Pins:** - PIN1 [pin 1] - PIN2 [pin 2] - PIN3 [pin 3] ### Q1 — [BSS138](https://www.flux.ai/lcsc/bss138~j6kt.md) - LCSC Part Number: C112239 - Package or Case Code: SOT-23-3_L2.9-W1.6-P1.90-LS2.8-BR - Continuous Drain Current: 200mA - Product Info Url: https://lcsc.com/product-detail/MOSFET_BSS138_C112239.html - Part Type: MOSFETs - JLCPCB Part Class: Extended Part - Role: Relay Driver - Transistor Type: N-channel MOSFET - Manufacturer Part Number: BSS138 - Role Details: 3.3V GPIO low-side MOSFET driver for K2 coil - Drain to Source Voltage: 50V - Manufacturer Name: SHIKUES(时科) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1811101310_Shikues-BSS138_C112239.pdf **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q2 — [BSS138](https://www.flux.ai/lcsc/bss138~j6kt.md) - JLCPCB Part Class: Extended Part - Part Type: MOSFETs - Product Info Url: https://lcsc.com/product-detail/MOSFET_BSS138_C112239.html - Continuous Drain Current: 200mA - Package or Case Code: SOT-23-3_L2.9-W1.6-P1.90-LS2.8-BR - LCSC Part Number: C112239 - Role Details: 3.3V GPIO low-side MOSFET driver for K2 coil - Manufacturer Part Number: BSS138 - Transistor Type: N-channel MOSFET - Role: Relay Driver - Manufacturer Name: SHIKUES(时科) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1811101310_Shikues-BSS138_C112239.pdf - Drain to Source Voltage: 50V **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Rasbery pi pico — [Raspberry Pi Pico](https://www.flux.ai/baronunread/raspberry-pi-pico~j7.md) - Datasheet URL: https://datasheets.raspberrypi.com/pico/pico-datasheet.pdf - Role: Microcontroller - Manufacturer Name: Raspberry Pi - Manufacturer Part Number: SC0915 - Role Details: Firmware energizes relays only while GPS fix is valid; immediate dropout on invalid/timeout - Part Type: Evaluation Boards **Pins:** - ~RUN [pin 30] - 3V3_EN [pin 37] - 3V3_OUT [pin 36] - ADC_VREF [pin 35] - AGND [pin 33] - GND [pin 13] - GND [pin D2] - GND [pin 23] - GND [pin 28] - GND [pin 18] - GND [pin 3] - GND [pin 38] - GND [pin 8] - GP0 [pin 1] - GP1 [pin 2] - GP10 [pin 14] - GP11 [pin 15] - GP12 [pin 16] - GP13 [pin 17] - GP14 [pin 19] - GP15 [pin 20] - GP16 [pin 21] - GP17 [pin 22] - GP18 [pin 24] - GP19 [pin 25] - GP2 [pin 4] - GP20 [pin 26] - GP21 [pin 27] - GP22 [pin 29] - GP26 [pin 31] - GP27 [pin 32] - GP28 [pin 34] - GP3 [pin 5] - GP4 [pin 6] - GP5 [pin 7] - GP6 [pin 9] - GP7 [pin 10] - GP8 [pin 11] - GP9 [pin 12] - SWCLK [pin D1] - SWDIO [pin D3] - VBUS [pin 40] - VSYS [pin 39] ### Relay 1 — [SRD-05VDC-SL-C](https://www.flux.ai/vasy_skral/srd-05vdc-sl-c~go1.md) - Datasheet URL: https://www.circuitbasics.com/wp-content/uploads/2015/11/SRD-05VDC-SL-C-Datasheet.pdf - Role: Relay - Manufacturer Part Number: SRD-05VDC-SL-C - Part Type: Relay - Role Details: 5V coil SPDT relay, contacts used for 12/24VDC up to 3A load - Manufacturer Name: Ningbo Songle Relay **Pins:** - A1 [pin A1] - A2 [pin A2] - COM [pin COM] - NC [pin NC] - NO [pin NO] ### Relay 2 — [SRD-05VDC-SL-C](https://www.flux.ai/vasy_skral/srd-05vdc-sl-c~go1.md) - Datasheet URL: https://www.circuitbasics.com/wp-content/uploads/2015/11/SRD-05VDC-SL-C-Datasheet.pdf - Manufacturer Part Number: SRD-05VDC-SL-C - Part Type: Relay - Manufacturer Name: Ningbo Songle Relay - Role Details: 5V coil SPDT relay, contacts used for 12/24VDC up to 3A load - Role: Relay **Pins:** - A1 [pin A1] - A2 [pin A2] - COM [pin COM] - NC [pin NC] - NO [pin NO] ### RTC — [DS3231SN#](https://www.flux.ai/jecstronic/ds3231sn~qc3.md) - Manufacturer Part Number: DS3231SN# - Part Type: Integrated Circuit - Manufacturer Name: Analog Devices Inc./Maxim Integrated - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.analog.com/media/en/technical-documentation/data-sheets/DS3231.pdf **Pins:** - ~INT~/SQW [pin 3] - ~RST [pin 4] - 32KHZ [pin 1] - GND [pin 13] - N.C._1 [pin 5] - N.C._2 [pin 6] - N.C._3 [pin 7] - N.C._4 [pin 8] - N.C._5 [pin 9] - N.C._6 [pin 10] - N.C._7 [pin 11] - N.C._8 [pin 12] - SCL [pin 16] - SDA [pin 15] - VBAT [pin 14] - VCC [pin 2] ### SMT Conn — [U.FL-R-SMT-1(01)](https://www.flux.ai/lcsc/upfl-r-smt-101~qrdh.md) - Package or Case Code: RF-SMD_U.FL-R-SMT-1-80 - Product Info Url: https://lcsc.com/product-detail/presales_HRS-Hirose-HRS-U-FL-R-SMT-1-01_C598199.html - LCSC Part Number: C598199 - Manufacturer Name: HRS(广濑) - JLCPCB Part Class: Extended Part - Part Type: RF Connectors / Coaxial Connectors - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2410010203_HRS-Hirose-U-FL-R-SMT-1-01_C598199.pdf - Manufacturer Part Number: U.FL-R-SMT-1(01) **Pins:** - GND [pin 1] - GND [pin 3] - SIN [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/alexb123/gps-dual-relay-switch~sl](https://www.flux.ai/alexb123/gps-dual-relay-switch~sl).* --- *Generated from [https://www.flux.ai/alexb123/gps-dual-relay-switch~sl](https://www.flux.ai/alexb123/gps-dual-relay-switch~sl)*