# Hybrid EEG BCI for Pluto X v1.1 ## Description Hybrid EEG BCI for Pluto X v1.1 using ESP32-WROOM-32 and ADS1299-6PAG with LiPo charging, 5V boost, -5V analog rail, split 3.3V analog/digital regulators, six EEG channels, RC electrode protection, and 80x60mm mixed-signal PCB constraints. ## Project Details - **Owner:** prajwalk04 - **Created:** 4/6/2026 - **Last Updated:** 4/7/2026 - **Visibility:** Public - **System Architecture:** ```mermaid flowchart TD BATT[LiPo 3.7V Battery] --> CHG[TP4056 Charger] CHG --> VBAT[VBAT Rail] VBAT --> BOOST[MT3608 Boost 5V] BOOST --> V5[5V Rail] V5 --> INV[ICL7660 Inverter] INV --> VN5[-5V Rail] V5 --> LDOA[LM1117 3.3V Analog] V5 --> LDOD[LM1117 3.3V Digital] LDOA --> AVDD[3.3V Analog] LDOD --> DVDD[3.3V Digital] AVDD --> ADS[ADS1299 EEG AFE] VN5 --> ADS DVDD --> ESP[ESP32 WROOM 32] ADS -->|SPI and control| ESP ELEC[EEG Electrodes] --> RC[2.2k and 1nF Input Filters] RC --> ADS ADS --> BIAS[Bias and Reference Network] BIAS --> ELEC AGND[AGND] --> STAR[Star Ground] DGND[DGND] --> STAR STAR --> ADS ``` ## Key Components ### J1 — [S2B-PH-K-S(LF)(SN)](https://www.flux.ai/lcsc/s2b-ph-k-slfsn.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_JST-S2B-PH-K-S-LF-SN_C173752.pdf - Manufacturer Part Number: S2B-PH-K-S(LF)(SN) - Manufacturer Name: JST - Role: Battery Connector - Package: JST-PH-2 - JLCPCB Part Class: Extended Part - Role Details: Mating connector: JST PHR-2 housing with SPH-002T-P0.5S crimp contacts - Part Type: Wire To Board / Wire To Wire Connector - Product Info Url: https://lcsc.com/product-detail/PH-Connectors_JST-Sales-America_S2B-PH-K-S-LF-SN_JST-Sales-America-S2B-PH-K-S-LF-SN_C173752.html - LCSC Part Number: C173752 - Package or Case Code: CONN-TH_S2B-PH-K-S-LF-SN **Pins:** - 1 [pin 1] - 2 [pin 2] ### J2 — [B8B-PH-K-S(LF)(SN)](https://www.flux.ai/jecstronic/b8b-ph-k-slfsn.md) - Manufacturer Part Number: B8B-PH-K-S(LF)(SN) - Package: JST-PH-8 - Part Type: Connector - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Mating connector: JST PHR-8 housing for FP1 FP2 Oz O1 O2 POz mastoid bias/reference leads - Role: Electrode Connector - Manufacturer Name: JST Sales America Inc. **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] ### U1 — [ESP32-WROOM-32 - 5482847](https://www.flux.ai/kicad-part-library/esp32-wroom-32-5482847.md) - Package or Case Code: ESP32-WROOM-32 - Package: Module - Role: MCU - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf - Part Type: RF Module - Manufacturer Name: Texas Instruments Inc. - Role Details: ESP32-WROOM-32 main controller; SPI master to ADS1299; WiFi/BLE link - Manufacturer Part Number: ESP32-WROOM-32 **Pins:** - EN [pin 3] - GND [pin 39] - GND [pin 15] - GND [pin 1] - GND [pin 38] - IO0 [pin 25] - IO12 [pin 14] - IO13 [pin 16] - IO14 [pin 13] - IO15 [pin 23] - IO16 [pin 27] - IO17 [pin 28] - IO18 [pin 30] - IO19 [pin 31] - IO2 [pin 24] - IO21 [pin 33] - IO22 [pin 36] - IO23 [pin 37] - IO25 [pin 10] - IO26 [pin 11] - IO27 [pin 12] - IO32 [pin 8] - IO33 [pin 9] - IO34 [pin 6] - IO35 [pin 7] - IO4 [pin 26] - IO5 [pin 29] - NC [pin 32] - RXD0/IO3 [pin 34] - SCK/CLK [pin 20] - SCS/CMD [pin 19] - SDI/SD1 [pin 22] - SDO/SD0 [pin 21] - SENSOR_VN [pin 5] - SENSOR_VP [pin 4] - SHD/SD2 [pin 17] - SWP/SD3 [pin 18] - TXD0/IO1 [pin 35] - VDD [pin 2] ### U2 — [ADS1299-6PAG](https://www.flux.ai/adrian95/ads1299-6pag.md) - Role: EEG AFE - Package: TQFP-64 - Manufacturer Name: Texas Instruments - Role Details: 6-channel biopotential ADC front end with SPI interface and bias/reference network - Datasheet URL: https://www.ti.com/lit/ds/symlink/ads1299.pdf - Manufacturer Part Number: ADS1299-6PAG - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit **Pins:** - ~CS [pin 39] - ~DRDY [pin 47] - ~PWDN [pin 35] - ~RESET [pin 36] - AVDD_1 [pin 19] - AVDD_2 [pin 21] - AVDD_3 [pin 22] - AVDD_4 [pin 56] - AVDD_5 [pin 59] - AVDD1 [pin 54] - AVSS_1 [pin 20] - AVSS_2 [pin 23] - AVSS_3 [pin 32] - AVSS_4 [pin 57] - AVSS_5 [pin 58] - 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_1 [pin 33] - DGND_2 [pin 49] - DGND_3 [pin 51] - DIN [pin 34] - DOUT [pin 43] - DVDD_1 [pin 48] - DVDD_2 [pin 50] - 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_1 [pin 27] - NC_2 [pin 29] - 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] ### U3 — [TP4056](https://www.flux.ai/vasy_skral/tp4056.md) - Role: Battery Charger - Role Details: Charges 3.7V LiPo cell from 5V input - Package: SOP-8 - Part Type: Integrated Circuit - Manufacturer Part Number: TP4056 - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: NanJing Top Power ASIC Corp. - Datasheet URL: https://dlnmh9ip6v2uc.cloudfront.net/datasheets/Prototyping/TP4056.pdf **Pins:** - ~CHRG [pin 7] - ~STDBY [pin 6] - BAT [pin 5] - CE [pin 8] - EP [pin 9] - GND [pin 3] - PROG [pin 2] - TEMP [pin 1] - VCC [pin 4] ### U4 — [MT3608 - 4414693](https://www.flux.ai/kicad-part-library/mt3608-4414693.md) - Package or Case Code: SOT-23-6 - Manufacturer Part Number: MT3608 - Role: Boost Converter - Datasheet URL: https://www.olimex.com/Products/Breadboarding/BB-PWR-3608/resources/MT3608.pdf - Role Details: Boosts VBAT to +5V rail for analog and digital regulators - Package: SOT-23-6 **Pins:** - EN [pin 4] - FB [pin 3] - GND [pin 2] - IN [pin 5] - NC [pin 6] - SW [pin 1] ### U5 — [ICL7660ESA+T](https://www.flux.ai/lcsc/icl7660esaplust.md) - Manufacturer Part Number: ICL7660ESA+T - Package: SOIC-8 - JLCPCB Part Class: Extended Part - Part Type: DC-DC Converters - Product Info Url: https://lcsc.com/product-detail/New-Quadratic-Unclassified-Data_Maxim-Integrated-ICL7660ESA-T_C407899.html - Role: Charge Pump Inverter - LCSC Part Number: C407899 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Analog-Devices-Inc--Maxim-Integrated-ICL7660ESA-T_C407899.pdf - Package or Case Code: SO-8_L4.9-W3.9-P1.27-LS5.9-BL - Role Details: Generates -5V analog rail from +5V - Manufacturer Name: ADI(亚德诺)/MAXIM(美信) **Pins:** - (N.C.)BOOST [pin 1] - CAP- [pin 4] - CAP+ [pin 2] - GND [pin 3] - LV [pin 6] - OSC [pin 7] - V+ [pin 8] - VOUT [pin 5] ### U6 — [LM1117MP-3.3/NOPB](https://www.flux.ai/adrian95/lm1117mp-3p3nopb.md) - Part Type: Integrated Circuit - Manufacturer Name: Texas Instruments - Package: SOT-223 - Datasheet URL: http://www.ti.com/general/docs/suppproductinfo.tsp?distId=10&gotoUrl=http%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Flm1117 - Role: Analog LDO - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: LM1117MP-3.3/NOPB - Role Details: Generates +3V3_A for ADS1299 analog and reference circuitry - Package or Case Code: SOT230P700X180-4N **Pins:** - ADJ/GND [pin 1] - INPUT [pin 3] - OUTPUT [pin 2] - VOUT [pin 4] ### U7 — [LM1117MP-3.3/NOPB](https://www.flux.ai/adrian95/lm1117mp-3p3nopb.md) - Package: SOT-223 - Package or Case Code: SOT230P700X180-4N - Part Type: Integrated Circuit - Manufacturer Name: Texas Instruments - Datasheet URL: http://www.ti.com/general/docs/suppproductinfo.tsp?distId=10&gotoUrl=http%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Flm1117 - Role Details: Generates +3V3_D for ESP32 and ADS1299 digital supply - Role: Digital LDO - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: LM1117MP-3.3/NOPB **Pins:** - ADJ/GND [pin 1] - INPUT [pin 3] - OUTPUT [pin 2] - VOUT [pin 4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/prajwalk04/hybrid-eeg-bci-for-pluto-x-v1p1](https://www.flux.ai/prajwalk04/hybrid-eeg-bci-for-pluto-x-v1p1).* --- *Generated from [https://www.flux.ai/prajwalk04/hybrid-eeg-bci-for-pluto-x-v1p1](https://www.flux.ai/prajwalk04/hybrid-eeg-bci-for-pluto-x-v1p1)*