# USB-C Environmental Biosensor Node ## Description Low-power USB-C 5V environmental sensor node with robust input protection, ESP32 Wi-Fi/BLE connectivity, digital temperature/humidity sensing, Bluetooth peripheral syncing, and EEG/PPG sensor interfaces for prototype biosignal acquisition. ## Project Details - **Owner:** okhellothere - **Created:** 4/3/2026 - **Last Updated:** 4/3/2026 - **Visibility:** Public ## Key Components ### D1 — [SP0503BAHT](https://www.flux.ai/kicad-part-library/sp0503baht.md) - Package or Case Code: SOT-143 - Role Details: Protects USB VBUS and data lines from ESD and surge events - Role: ESD Protection - Package: SOT-143 - Datasheet URL: http://www.littelfuse.com//media/files/littelfuse/technical%20resources/documents/data%20sheets/sp05xxba.pdf - Manufacturer Part Number: SP0503BAHT - Manufacturer Name: Texas Instruments Inc. **Pins:** - A [pin 1] - K [pin 3] - K [pin 4] - K [pin 2] ### IC1 — [MAX30102EFD+](https://www.flux.ai/adrian95/max30102efdplus.md) - Package: Optical Sensor - Manufacturer Part Number: MAX30102EFD+ - Manufacturer Name: Analog Devices Inc./Maxim Integrated - Role: PPG Sensor - Part Type: Sensor - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Integrated PPG optical heart-rate sensor interface - Datasheet URL: https://cdn.sparkfun.com/assets/8/3/c/3/2/MAX30102_Datasheet.pdf **Pins:** - ~INT [pin 13] - GND [pin 12] - IR_DRV [pin 6] - N.C._1 [pin 1] - N.C._2 [pin 7] - N.C._3 [pin 8] - N.C._4 [pin 14] - PGND [pin 4] - R_DRV [pin 5] - SCL [pin 2] - SDA [pin 3] - VDD [pin 11] - VLED+_1 [pin 9] - VLED+_2 [pin 10] ### J1 — [Type-C-2.0-6Pin](https://www.flux.ai/jharwinbarrozo/type-c-20-6pin.md) - Role Details: USB-C sink-only 5V input for the sensor node - Package: USB-C - Datasheet URL: https://datasheet.lcsc.com/lcsc/2204071830_CIKI-Type-C-2-0-6Pin_C2987385.pdf - Role: Power Input Connector - Part Type: Connector - Manufacturer Name: CIKI - Manufacturer Part Number: Type-C-2.0-6Pin **Pins:** - CC1 - CC2 - GND - GND__1 - SHIELD - SHIELD__1 - SHIELD__2 - SHIELD__3 - V-BUS - V-BUS__1 ### J2 — [BG300-06-A-L-A](https://www.flux.ai/tyler-s/bg300-06-a-l-a.md) - Role Details: External EEG electrode and reference interface connector - Purchase Url: https://www.digikey.com/en/products/detail/gct/BG300-06-A-L-A/9859597 - Role: EEG Connector - Manufacturer Part Number: BG300-06-A-L-A - Package: Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] ### J3 — [5055680471](https://www.flux.ai/adrian95/5055680471.md) - Package: Connector - Role: PPG Connector - Part Type: Connector - Datasheet URL: https://www.molex.com/pdm_docs/sd/5055680231_sd.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Molex - Manufacturer Part Number: 5055680471 - Role Details: Compact connector for external PPG or optical sensor expansion **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### U1 — [ESP32-C3-MINI-1-N4](https://www.flux.ai/adrian95/esp32-c3-mini-1-n4.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Espressif - Part Type: Module - Role: Wireless MCU - Manufacturer Part Number: ESP32-C3-MINI-1-N4 - Role Details: Ultra-low-power Wi-Fi 802.11 b/g/n and BLE 5.x controller for environmental and biosensor node - Integrated Circuit Type: RF Device - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-c3-mini-1_datasheet_en.pdf - Package: Module **Pins:** - 3V3 [pin 3] - EN [pin 8] - GND [pin 14] - GND [pin 49_5] - GND [pin 48] - GND [pin 52] - GND [pin 45] - GND [pin 2] - GND [pin 49_8] - GND [pin 1] - GND [pin 49_9] - GND [pin 49_2] - GND [pin 53] - GND [pin 49_6] - GND [pin 43] - GND [pin 42] - GND [pin 44] - GND [pin 49_7] - GND [pin 51] - GND [pin 46] - GND [pin 39] - GND [pin 41] - GND [pin 50] - GND [pin 49_3] - GND [pin 11] - GND [pin 38] - GND [pin 40] - GND [pin 37] - GND [pin 49_1] - GND [pin 49_4] - GND [pin 47] - GND [pin 36] - IO0 [pin 12] - IO1 [pin 13] - IO10 [pin 16] - IO18 [pin 26] - IO19 [pin 27] - IO2 [pin 5] - IO3 [pin 6] - IO4 [pin 18] - IO5 [pin 19] - IO6 [pin 20] - IO7 [pin 21] - IO8 [pin 22] - IO9 [pin 23] - NC [pin 32] - NC [pin 15] - NC [pin 34] - NC [pin 4] - NC [pin 29] - NC [pin 33] - NC [pin 17] - NC [pin 25] - NC [pin 10] - NC [pin 9] - NC [pin 24] - NC [pin 28] - NC [pin 7] - NC [pin 35] - RXD0 [pin 30] - TXD0 [pin 31] ### U2 — [SHT31-DIS-B2.5KS](https://www.flux.ai/vasy_skral/sht31-dis-b25ks.md) - Package: DFN - Manufacturer Name: Sensirion AG - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/Sensirion%20PDFs/HT_DS_SHT3x_DIS.pdf - Part Type: Integrated Circuit - Role Details: I2C temperature and humidity sensor - Manufacturer Part Number: SHT31-DIS-B2.5KS - Role: Environmental Sensor **Pins:** - ~RESET [pin 6] - ADDR [pin 2] - ALERT [pin 3] - R [pin 7] - SCL [pin 4] - SDA [pin 1] - VDD [pin 5] - VSS [pin 9] - VSS [pin 8] ### U3 — [ADS1299-4PAGR](https://www.flux.ai/lcsc/ads1299-4pagr.md) - Package: TQFP-64 - JLCPCB Part Class: Extended Part - Role Details: Low-noise EEG analog front end for external electrode interface - Package or Case Code: TQFP-64_L10.0-W10.0-P0.50-LS12.0-BL - Manufacturer Name: TI(德州仪器) - Role: EEG AFE - Manufacturer Part Number: ADS1299-4PAGR - LCSC Part Number: C2651574 **Pins:** - ~{CS} [pin 39] - ~{DRDY} [pin 47] - ~{PWDN} [pin 35] - ~{RESET} [pin 36] - AVDD [pin 56] - AVDD [pin 59] - AVDD [pin 21] - AVDD [pin 19] - AVDD [pin 22] - AVDD1 [pin 54] - AVSS [pin 20] - AVSS [pin 32] - AVSS [pin 58] - AVSS [pin 23] - AVSS [pin 57] - AVSS1 [pin 53] - BIASIN [pin 62] - BIASINV [pin 61] - BIASOUT [pin 63] - BIASREF [pin 60] - CLK [pin 37] - CLKSEL [pin 52] - DAISY_IN [pin 41] - DGND [pin 33] - DGND [pin 51] - DGND [pin 49] - DIN [pin 34] - DOUT [pin 43] - DVDD [pin 50] - DVDD [pin 48] - GPIO1 [pin 42] - GPIO2 [pin 44] - GPIO3 [pin 45] - GPIO4 [pin 46] - IN1N [pin 15] - IN1P [pin 16] - IN2N [pin 13] - IN2P [pin 14] - IN3N [pin 11] - IN3P [pin 12] - IN4N [pin 9] - IN4P [pin 10] - IN5N [pin 7] - IN5P [pin 8] - IN6N [pin 5] - IN6P [pin 6] - IN7N [pin 3] - IN7P [pin 4] - IN8N [pin 1] - IN8P [pin 2] - NC [pin 29] - NC [pin 27] - RESERVED [pin 64] - RESV1 [pin 31] - SCLK [pin 40] - SRB1 [pin 17] - SRB2 [pin 18] - START [pin 38] - VCAP1 [pin 28] - VCAP2 [pin 30] - VCAP3 [pin 55] - VCAP4 [pin 26] - VREFN [pin 25] - VREFP [pin 24] ### U4 — [MIC5219-3.3YM5-TR](https://www.flux.ai/adrian95/mic5219-33ym5-tr.md) - Manufacturer Name: Microchip - Package: SOT-23-5 - Part Type: Integrated Circuit - Role: LDO Regulator - Manufacturer Part Number: MIC5219-3.3YM5-TR - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Low-noise 3.3V regulator for ESP32, environmental sensor, and biosignal interfaces - Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/MIC5219-500mA-Peak-Output-LDO-Regulator-DS20006021A.pdf **Pins:** - BP [pin 4] - EN [pin 3] - GND [pin 2] - IN [pin 1] - OUT [pin 5] ### U5 — [TPS2592xx - 367482](https://www.flux.ai/kicad-part-library/tps2592xx-367482.md) - Datasheet URL: http://www.ti.com/lit/ds/symlink/tps25925.pdf - Package: VSON-10 - Role Details: Provides USB input OVP, UVLO, OCP and reverse current blocking on 5V input - Package or Case Code: VSON-10-1EP_3x3mm_P0.5mm_EP1.65x2.4mm_ThermalVias - Manufacturer Name: Texas Instruments Inc. - Manufacturer Part Number: TPS2592xx - Role: eFuse Protection **Pins:** - dV/dT [pin 1] - EN/UVLO [pin 2] - GND [pin 11] - ILIM [pin 10] - NC [pin 9] - OUT [pin 8] - OUT [pin 6] - OUT [pin 7] - VIN [pin 3] - VIN [pin 5] - VIN [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/okhellothere/usb-c-environmental-biosensor-node](https://www.flux.ai/okhellothere/usb-c-environmental-biosensor-node).* --- *Generated from [https://www.flux.ai/okhellothere/usb-c-environmental-biosensor-node](https://www.flux.ai/okhellothere/usb-c-environmental-biosensor-node)*