# 868 MHz Horn Pulse Receiver ## Description Disposable battery-powered EU 868 MHz long-range receiver providing a nominal 12 V, 1 A, 10 ms pulse to a horn at approximately 1 km line of sight. ## Project Details - **Owner:** unkalumpa - **Created:** 7/22/2026 - **Last Updated:** 7/22/2026 - **Visibility:** Public ## Key Components ### D1 — [SS56](https://www.flux.ai/lcsc/ss56~hea6.md) - Role: Flyback / Freewheeling - Datasheet URL: https://www.lcsc.com/datasheet/C65009.pdf?spm=wm.sxq.inf.ggs___wm.ssy.bg.0.xh&lcsc_vid=T1kIXgFeT1NaU1RXQFBbUlUHT1cKU1NXFVBeX1VSTlAxVlNRTlhaXlxfQlZWUjsOAxUeFF5JWBYZEEoKFBINSQcJGk4dAgUUFAk%3D - Manufacturer Name: MDD(Microdiode Semiconductor) - Voltage Rating: 60V - Forward Voltage: 0.55V - Manufacturer Part Number: SS56 - Part Type: Schottky Barrier Diodes (SBD) - Reverse Voltage: 60V - License: https://creativecommons.org/licenses/by/4.0/ - LCSC Part Number: C65009 - Role Details: 60 V 5 A Schottky clamps horn inductive current from HORN_SW back to CAP12. - Package or Case Code: SMC_L6.9-W5.9-LS7.9-R-RD - Diode Type: Schottky Diode - Current Rating: 5A - JLCPCB Part Class: Extended Part **Pins:** - A [pin 1] - K [pin 2] ### J1 — [B2B-PH-K-S(LF)(SN)](https://www.flux.ai/lcsc/b2b-ph-k-slfsn~yvsw.md) - Role Details: 2-pin 2 A connector; pin 1 is A23 positive BAT12 and pin 2 is GND; polarity must be observed. - Role: Power Conversion - LCSC Part Number: C131337 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_JST-B2B-PH-K-S-LF-SN_C131337.pdf - Manufacturer Part Number: B2B-PH-K-S(LF)(SN) - Part Type: Wire To Board / Wire To Wire Connector - Connector Positions: 2 - Product Info Url: https://lcsc.com/product-detail/PH-Connectors_JST_B2B-PH-K-S-LF-SN_B2B-PH-K-S-LF-SN_C131337.html - Connector Pitch: 2mm - Connector Rows: 1 - Package or Case Code: CONN-TH_B2B-PH-K-S - JLCPCB Part Class: Extended Part - Connector Type: Wire To Board Connector - Manufacturer Name: JST - Connector Gender: Male **Pins:** - 1 [pin 1] - 2 [pin 2] ### J2 — [B2B-PH-K-S(LF)(SN)](https://www.flux.ai/lcsc/b2b-ph-k-slfsn~yvsw.md) - Connector Gender: Male - Manufacturer Name: JST - Role: Switching - Connector Type: Wire To Board Connector - JLCPCB Part Class: Extended Part - Package or Case Code: CONN-TH_B2B-PH-K-S - Connector Rows: 1 - Role Details: 2-pin 2 A horn interface; pin 1 CAP12 and pin 2 HORN_SW. - Connector Pitch: 2mm - Product Info Url: https://lcsc.com/product-detail/PH-Connectors_JST_B2B-PH-K-S-LF-SN_B2B-PH-K-S-LF-SN_C131337.html - Connector Positions: 2 - Part Type: Wire To Board / Wire To Wire Connector - Manufacturer Part Number: B2B-PH-K-S(LF)(SN) - LCSC Part Number: C131337 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_JST-B2B-PH-K-S-LF-SN_C131337.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] ### J3 — [Pin Header 01x03 2.54mm Horizontal](https://www.flux.ai/adrian95/pin-header-01x03-254mm-horizontal~tgh.md) - Role: Signal Generation - Part Type: Connector - Role Details: Minimal 3-pin UPDI programming interface carrying UPDI, +3V3, and GND. - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J4 — [WIRE_3P](https://www.flux.ai/cherepanyadima/wire3p~rk.md) - Part Type: Connectors - Mount: Solder - Role Details: Use pad 1 for an approximately 86 mm wire antenna; pads 2 and 3 intentionally unused. - Symbol Style: Parametric - Role: RF Tuning / Matching - Manufacturer Part Number: WIRE_3P **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] ### Q1 — [SQ4435EY-T1_GE3](https://www.flux.ai/adrian95/sq4435ey-t1ge3.md) - Symbol Style: parametric-v1 - Part Type: Transistors - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/user-uploaded/05113df3183a01482a42eec4612192362c966fd5cebebb128490c8ca1b758f63.pdf - Role: Switching - Role Details: 30 V P-channel high-side switch disconnects the 4700 uF storage capacitor during standby. - Manufacturer Name: Vishay Siliconix - Current Rating: 15A - Manufacturer Part Number: SQ4435EY-T1_GE3 - Voltage Rating: 30V **Pins:** - D_1 [pin 5] - D_2 [pin 6] - D_3 [pin 7] - D_4 [pin 8] - G [pin 4] - S_1 [pin 1] - S_2 [pin 2] - S_3 [pin 3] ### Q2 — [AO3400A](https://www.flux.ai/adrian95/ao3400a~ug9.md) - Voltage Rating: 30V - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: 30 V NMOS translates 3.3 V CAP_CHARGE_EN to a 12 V-side P-MOS gate pull-down. - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/Alpha%20&%20Omega/AO3400A_ds.pdf - Manufacturer Part Number: AO3400A - Role: Logic-level Shifting - Manufacturer Name: Alpha & Omega Semiconductor Inc. - Part Type: Transistor **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### Q3 — [AO3400A](https://www.flux.ai/adrian95/ao3400a~ug9.md) - Manufacturer Name: Alpha & Omega Semiconductor Inc. - Voltage Rating: 30V - Part Type: Transistor - Role Details: 30 V logic-level NMOS, about 48 mΩ at 2.5 V gate drive, switches the 1 A horn for 10 ms. - Role: Switching - Manufacturer Part Number: AO3400A - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/Alpha%20&%20Omega/AO3400A_ds.pdf - Current Rating: 5.7A - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### U1 — [TPS70933DBVR](https://www.flux.ai/adrian95/tps70933dbvr~uql.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps709.pdf - Manufacturer Part Number: TPS70933DBVR - Manufacturer Name: Texas Instruments - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ - Role: Power Conversion - Role Details: 30 V input, 3.3 V 150 mA nano-power LDO sized for MCU plus SX1262 receive load. **Pins:** - EN [pin 3] - GND [pin 2] - IN [pin 1] - NC [pin 4] - OUT [pin 5] ### U2 — [ATTINY1614-SSFR](https://www.flux.ai/lcsc/attiny1614-ssfr~urw0.md) - Manufacturer Name: MICROCHIP(美国微芯) - JLCPCB Part Class: Extended Part - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Microchip-Tech-ATTINY1614-SSFR_C141724.pdf - Package or Case Code: SOIC-14_L8.7-W3.9-P1.27-LS6.0-BL - Part Type: ATMEL & AVR - Role: Signal Generation - Product Info Url: https://lcsc.com/product-detail/ATMEL-AVR_Microchip-Tech_ATTINY1614-SSFR_Microchip-Tech-ATTINY1614-SSFR_C141724.html - Role Details: Low-power MCU uses internal clock, SPI radio control, UPDI programming, charge enable, and 10 ms horn timing. - LCSC Part Number: C141724 - Manufacturer Part Number: ATTINY1614-SSFR **Pins:** - GND [pin 14] - PA0/~{RESET}/UPDI [pin 10] - PA1 [pin 11] - PA2 [pin 12] - PA3/EXTCLK [pin 13] - PA4 [pin 2] - PA5 [pin 3] - PA6 [pin 4] - PA7 [pin 5] - PB0 [pin 9] - PB1 [pin 8] - TOSC1/PB3 [pin 6] - TOSC2/PB2 [pin 7] - VDD [pin 1] ### U3 — [E22-900M22S](https://www.flux.ai/lcsc/e22-900m22s~cetv.md) - Product Info Url: https://lcsc.com/product-detail/Wireless-Modules_Chengdu-Ebyte-Elec-Tech-E22-900M22S_C411293.html - Manufacturer Part Number: E22-900M22S - JLCPCB Part Class: Extended Part - Manufacturer Name: EBYTE(亿佰特) - Part Type: LoRa Modules - Role Details: SX1262 850-930 MHz SMD module with integrated RF matching for 868 MHz long-range reception. - Package or Case Code: WIRELM-SMD_E22-900M22S - LCSC Part Number: C411293 - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2409251704_Chengdu-Ebyte-Elec-Tech-E22-900M22S_C411293.pdf - Role: Modulation / Demodulation - Symbol Style: parametric-v1 **Pins:** - ANT [pin 21] - BUSY [pin 14] - DIO1 [pin 13] - DIO2 [pin 8] - GND [pin 20] - GND [pin 3] - GND [pin 4] - GND [pin 5] - GND [pin 10] - GND [pin 12] - GND [pin 1] - GND [pin 11] - GND [pin 2] - GND [pin 22] - MISO [pin 16] - MOSI [pin 17] - NRST [pin 15] - NSS [pin 19] - RXEN [pin 6] - SCK [pin 18] - TXEN [pin 7] - VCC [pin 9] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/unkalumpa/868-mhz-horn-pulse-receiver~bg](https://www.flux.ai/unkalumpa/868-mhz-horn-pulse-receiver~bg).* --- *Generated from [https://www.flux.ai/unkalumpa/868-mhz-horn-pulse-receiver~bg](https://www.flux.ai/unkalumpa/868-mhz-horn-pulse-receiver~bg)*