# Melodic Moccasin Speeder Bike ## Description AeroHUD VariScope Mark 1 - ESP32-S3 RF module vario/airspeed HUD with Qwiic OLED and SDP810, GPS, USB-C data+charging ## Project Details - **Owner:** unluckynelson - **Created:** 3/7/2026 - **Last Updated:** 3/7/2026 - **Visibility:** Public - **Connectivity:** I2C bus to ICM-20948, BMP280, Qwiic OLED connector, Qwiic SDP810 connector (4-pin). UART to u-blox GNSS module. USB2 to ESP32-S3 via USB-C. - **Power Requirements:** USB-C 5V input for charging + USB2 data. Single-cell Li-ion battery. Generate +5V (boost) and +3.3V rails. Battery ADC divider to ESP32-S3 ADC. - **System Architecture:** flowchart TD subgraph Power [Power] USBC["USB-C Port"] --> CHG["Li-ion Charger"] BAT["Li-ion Battery"] --> CHG CHG --> VSYS["System Rail"] VSYS --> BOOST5["5V Boost"] VSYS --> LDO33["3.3V LDO"] BOOST5 --> V5["+5V Rail"] LDO33 --> V33["+3.3V Rail"] V33 --> ADC["Battery ADC Divider"] end subgraph MCU [MCU] ESP["ESP32-S3 RF Module"] end subgraph I2C [I2C Bus] OLED["OLED via Qwiic connector"] IMU["ICM-20948"] BARO["BMP280"] I2CEXT["Qwiic connector for SDP810"] SDP["SDP810-500PA external"] I2CEXT --> SDP end subgraph UART [UART] GPS["u-blox NEO-M8 GNSS"] end subgraph UI [User IO] ENC["Rotary Encoder"] BUZ["Buzzer"] LEDR["Red LED"] LEDB["Blue LED"] PWRBTN["Power Button (long-press)"] end USBC -->|"USB2 D+ D-"| ESP V33 --> ESP V33 --> IMU V33 --> BARO V33 --> OLED V33 --> I2CEXT ESP -->|"I2C"| IMU ESP -->|"I2C"| BARO ESP -->|"I2C"| OLED ESP -->|"I2C"| I2CEXT ESP -->|"UART"| GPS ESP --> ENC ESP --> BUZ ESP --> LEDR ESP --> LEDB ESP --> PWRBTN - **Human Interface:** Rotary encoder with pushbutton, buzzer, red+blue status LEDs, tactile long-press power button. ## Key Components ### BZ1 — [CPT-9019S-SMT-TR](https://www.flux.ai/jecstronic/cpt-9019s-smt-tr.md) - Manufacturer Part Number: CPT-9019S-SMT-TR - Manufacturer Name: CUI Devices - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Buzzer - Datasheet URL: https://www.cuidevices.com/product/resource/cpt-9019s-smt-tr.pdf - Role Details: Passive piezo transducer driven by MOSFET from MCU PWM - Role: Buzzer - Package: SMD **Pins:** - 1 [pin 1] - 2 [pin 2] ### IC1 — [ESP32-S3-WROOM-1-N16R8](https://www.flux.ai/adrian95/esp32-s3-wroom-1-n16r8.md) - Manufacturer Part Number: ESP32-S3-WROOM-1-N16R8 - Part Type: Module - License: https://creativecommons.org/licenses/by/4.0/ - Package: Module - Role Details: ESP32-S3 RF module with integrated antenna; provides I2C, UART, USB2 - Datasheet URL: https://www.mouser.com/datasheet/2/891/esp32_s3_wroom_1_wroom_1u_datasheet_en-2930317.pdf - Role: MCU - Manufacturer Name: Espressif Systems **Pins:** - 3V3 [pin 2] - EN [pin 3] - GND_1 [pin 1] - GND_10 [pin 48] - GND_11 [pin 49] - GND_2 [pin 40] - GND_3 [pin 41] - GND_4 [pin 42] - GND_5 [pin 43] - GND_6 [pin 44] - GND_7 [pin 45] - GND_8 [pin 46] - GND_9 [pin 47] - IO0 [pin 27] - IO1 [pin 39] - IO10 [pin 18] - IO11 [pin 19] - IO12 [pin 20] - IO13 [pin 21] - IO14 [pin 22] - IO15 [pin 8] - IO16 [pin 9] - IO17 [pin 10] - IO18 [pin 11] - IO19 [pin 13] - IO2 [pin 38] - IO20 [pin 14] - IO21 [pin 23] - IO3 [pin 15] - IO35 [pin 28] - IO36 [pin 29] - IO37 [pin 30] - IO38 [pin 31] - IO39 [pin 32] - IO4 [pin 4] - IO40 [pin 33] - IO41 [pin 34] - IO42 [pin 35] - IO45 [pin 26] - IO46 [pin 16] - IO47 [pin 24] - IO48 [pin 25] - IO5 [pin 5] - IO6 [pin 6] - IO7 [pin 7] - IO8 [pin 12] - IO9 [pin 17] - RXD0 [pin 36] - TXD0 [pin 37] ### IC2 — [MCP73871-4CCI/ML](https://www.flux.ai/adrian95/mcp73871-4cciml.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Single-cell Li-ion charger with power-path/load sharing from USB 5V - Package or Case Code: QFN50P400X400X100-21N-D - Manufacturer Part Number: MCP73871-4CCI/ML - Part Type: Integrated Circuit - Datasheet URL: https://www.arrow.com/en/products/mcp73871-4cciml/microchip-technology?region=nac - Role: Battery Charger - Manufacturer Name: Microchip - Datasheet URL: https://ww1.microchip.com/downloads/en/DeviceDoc/MCP73871-Data-Sheet-20002090E.pdf - Package: QFN-20 **Pins:** - ~PG [pin 6] - ~TE [pin 9] - CE [pin 17] - EP [pin 21] - IN_1 [pin 18] - IN_2 [pin 19] - OUT_1 [pin 1] - OUT_2 [pin 20] - PROG1 [pin 13] - PROG2 [pin 4] - PROG3 [pin 12] - SEL [pin 3] - STAT1/~LBO [pin 8] - STAT2 [pin 7] - THERM [pin 5] - VBAT_1 [pin 14] - VBAT_2 [pin 15] - VBAT_SENSE [pin 16] - VPCC [pin 2] - VSS_1 [pin 10] - VSS_2 [pin 11] ### J1 — [USB-C 2.0 Receptacle](https://www.flux.ai/corynrobinson/usb-c-20-receptacle.md) - Purchase Url: https://www.digikey.com/en/products/detail/gct/USB4105-GF-A/11198441 - Role: USB Connector - Manufacturer Name: GTC - Package: USB-C Receptacle - Manufacturer Part Number: USB4105-GF-A - Datasheet URL: https://gct.co/files/drawings/usb4105.pdf - Part Type: USB C - Role Details: USB-C receptacle for VBUS + USB2 D+/D- to ESP32-S3 **Pins:** - CC1 [pin 6] - CC2 [pin 12] - D- [pin 9] - D- [pin 7] - D+ [pin 10] - D+ [pin 8] - GND [pin 15] - GND [pin 1] - GND [pin 16] - GND [pin 2] - SBU1 [pin 11] - SBU2 [pin 5] - VBUS [pin 14] - VBUS [pin 13] - VBUS [pin 4] - VBUS [pin 3] ### J2 — [QWIIC I2C JST Connector](https://www.flux.ai/vasy_skral/qwiic-i2c-jst-connector.md) - Manufacturer Part Number: SM04B-SRSS-TB - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/JST%20PDFs/SR%20Connector.pdf - Manufacturer Name: JST Sales America Inc. - Part Type: Connector - Role: I2C Connector - Package: JST-SH-4 1.0mm RA - Role Details: 4-pin Qwiic: GND, 3.3V, SDA, SCL **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### J3 — [QWIIC I2C JST Connector](https://www.flux.ai/vasy_skral/qwiic-i2c-jst-connector.md) - Part Type: Connector - Package: JST-SH-4 1.0mm RA - Role Details: 4-pin Qwiic: GND, 3.3V, SDA, SCL - Manufacturer Name: JST Sales America Inc. - Manufacturer Part Number: SM04B-SRSS-TB - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/JST%20PDFs/SR%20Connector.pdf - Role: I2C Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### J4 — [PEC11R-4215F-S0024](https://www.flux.ai/vasyl/pec11r-4215f-s0024.md) - Part Type: Encoder - Role: Encoder - Manufacturer Name: Bourns Inc. - Role Details: Incremental quadrature encoder with pushbutton - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.bourns.com/docs/Product-Datasheets/PEC11R.pdf - Manufacturer Part Number: PEC11R-4215F-S0024 - Package: THT Encoder **Pins:** - ~ [pin 1] - ~ [pin 2] - A [pin A] - B [pin B] - COM [pin COM] - SHIELD [pin S1] - SHIELD__1 [pin S2] ### J5 — [S2B-PH-K-S(LF)(SN)](https://www.flux.ai/adrian95/s2b-ph-k-slfsn.md) - Datasheet URL: https://www.jst-mfg.com/product/pdf/eng/ePH.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Package: JST-PH-2 RA THT - Manufacturer Part Number: S2B-PH-K-S(LF)(SN) - Role: Battery Connector - Role Details: 2-pin JST-PH battery connector to Li-ion cell - Manufacturer Name: JST Sales America Inc. **Pins:** - P1 [pin 1] - P2 [pin 2] ### LED1 — [APG1608QBC/D](https://www.flux.ai/jecstronic/apg1608qbcd.md) - Manufacturer Part Number: APG1608QBC/D - Role: Indicator - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: LED - Role Details: Blue status LED for connectivity/status - Datasheet URL: https://www.kingbrightusa.com/images/catalog/SPEC/APG1608QBC-D.pdf - Manufacturer Name: Kingbright - Package: 0603 **Pins:** - A [pin 2] - K [pin 1] ### LED2 — [LTST-C190KRKT](https://www.flux.ai/adrian95/ltst-c190krkt.md) - Package: 0603 - Part Type: LED - Datasheet URL: https://optoelectronics.liteon.com/upload/download/DS-22-99-0151/LTST-C190KRKT.pdf - Manufacturer Name: Lite-On Inc. - Role: Indicator - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: LTST-C190KRKT - Role Details: Red status LED for charging/status **Pins:** - A [pin 2] - K [pin 1] ### Q1 — [BSS138](https://www.flux.ai/vasy_skral/bss138.md) - Datasheet URL: https://www.onsemi.com/pdf/datasheet/bss138-d.pdf - Package: SOT-23 - Role Details: N-MOSFET low-side driver for buzzer or small load - Manufacturer Name: onsemi - Role: Switch - Manufacturer Part Number: BSS138 - Part Type: Transistor **Pins:** - D [pin 3] - G [pin 1] - S [pin 2] ### S1 — [BMP280](https://www.flux.ai/jecstronic/bmp280.md) - Package: LGA-8 - Role: Barometer - Manufacturer Part Number: BMP280 - Part Type: Sensor - Datasheet URL: https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmp280-ds001.pdf - Manufacturer Name: Bosch Sensortec - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: BMP280 pressure sensor on I2C bus (addr strap 0x76/0x77) **Pins:** - CSB [pin 2] - GND [pin 7] - GND [pin 1] - SCK [pin 4] - SDI [pin 3] - SDO [pin 5] - VDD [pin 8] - VDDIO [pin 6] ### SW1 — [1571563-8](https://www.flux.ai/vasy_skral/1571563-8.md) - Role Details: Momentary tactile switch for long-press power control input to MCU - Package: SMD Tactile - Role: Button - Part Type: Switch - Manufacturer Part Number: 1571563-8 - Manufacturer Name: TE Connectivity ALCOSWITCH Switches - Datasheet URL: https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=1308111-1_SWITCHES_CORE_PROGRAM_CATALOG&DocType=CS&DocLang=English **Pins:** - ~ [pin 3] - ~ [pin 2] - ~ [pin 1] - ~ [pin 4] ### U1 — [ICM-20948](https://www.flux.ai/hakeem02/icm-20948-nl4no.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: TDK InvenSense - Package: QFN-24 - Compliance: RoHS,Green-Compliant - Datasheet URL: https://invensense.tdk.com/wp-content/uploads/2016/06/DS-000189-ICM-20948-v1.3.pdf - Package or Case Code: QFN50P350X450X80-25WN - Role: IMU - Part Type: IC - Manufacturer Part Number: ICM-20948+ - Role Details: 9-axis IMU on I2C bus (addr 0x68 with AD0 low) **Pins:** - AD0 / SDO [pin 9] - AUX_CL [pin 7] - AUX_DA [pin 21] - FSYNC [pin 11] - GND [pin 18] - INT1 [pin 12] - NC [pin 2] - NC [pin 5] - NC [pin 4] - NC [pin 1] - NC [pin 14] - NC [pin 16] - NC [pin 6] - NC [pin 17] - NC [pin 3] - NC [pin 15] - nCS [pin 22] - REGOUT [pin 10] - RESV [pin 20] - RESV [pin 19] - SCL / SCLK [pin 23] - SDA / SDI [pin 24] - VDD [pin 13] - VDDIO [pin 8] ### U2 — [NEO-M8N-0-10](https://www.flux.ai/jecstronic/neo-m8n-0-10.md) - Datasheet URL: https://www.mouser.ca/datasheet/2/1025/NEO_M8_FW3_DataSheet_UBX_15031086-3180589.pdf - Role Details: u-blox GNSS module on UART @ 9600 baud - Part Type: Module - Package: Module - Role: GNSS - Manufacturer Part Number: NEO-M8N-0-10 - Manufacturer Name: U-blox - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - D_SEL [pin 2] - EXTINT_/_EXTINT0 [pin 4] - GND_1 [pin 10] - GND_2 [pin 12] - GND_3 [pin 13] - GND_4 [pin 24] - LNA_EN/RESERVED [pin 14] - RESERVED_/_EXTINT1 [pin 15] - RESERVED_1 [pin 16] - RESERVED_2 [pin 17] - RESET_N [pin 8] - RF_IN [pin 11] - RXD_/_SPI_MOSI [pin 21] - SCL_/_SPI_CLK [pin 19] - SDA_/_SPI_CS_N [pin 18] - TIMEPULSE_/_TIMEPULSE1 [pin 3] - TP2/SAFEBOOT_N [pin 1] - TXD_/_SPI_MISO [pin 20] - USB_DM [pin 5] - USB_DP [pin 6] - V_BCKP [pin 22] - VCC [pin 23] - VCC_RF [pin 9] - VDD_USB [pin 7] ### U3 — [TLV75733PDBVR](https://www.flux.ai/lcsc/tlv75733pdbvr.md) - Manufacturer Name: TI(德州仪器) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Texas-Instruments-TLV75733PDBVR_C485517.pdf - Role Details: 3.3V LDO for ESP32-S3 and sensors - Manufacturer Part Number: TLV75733PDBVR - Product Info Url: https://lcsc.com/product-detail/New-Arrivals_Texas-Instruments-Texas-Instruments-TLV75733PDBVR_C485517.html - Package: SOT-23-5 - LCSC Part Number: C485517 - Dropout Voltage: 475mV@(1A) - Output Current: 1A - Package or Case Code: SOT-23-5_L2.9-W1.6-P0.95-LS2.8-BL - Max Input Voltage: 5.5V - Operating Temperature: -40℃~+125℃@(Tj) - JLCPCB Part Class: Extended Part - Max Output Voltage: 3.3V - Role: Regulator - Part Type: Linear Voltage Regulators (LDO) **Pins:** - EN [pin 3] - GND [pin 2] - IN [pin 1] - NC [pin 4] - OUT [pin 5] ### U4 — [USBLC6-2P6](https://www.flux.ai/kicad-part-library/usblc6-2p6.md) - Manufacturer Part Number: USBLC6-2P6 - Manufacturer Name: Texas Instruments Inc. - Role: ESD Protection - Role Details: Low-capacitance ESD protection for USB2 D+/D- - Datasheet URL: https://www.st.com/resource/en/datasheet/usblc6-2.pdf - Package or Case Code: SOT-666 - Package: SOT-23-6 **Pins:** - GND [pin 2] - I/O1 [pin 1] - I/O1 [pin 6] - I/O2 [pin 3] - I/O2 [pin 4] - VBUS [pin 5] ### U5 — [SDP810-500PA-D](https://www.flux.ai/lcsc/sdp810-500pa-d.md) - Manufacturer Part Number: SDP810-500PA-D - Package: Through Hole - Role: Airspeed Sensor - Part Type: Pressure Sensors - Manufacturer Name: Sensirion(瑞士盛思锐) - Datasheet URL: https://assets.lcsc.com/datasheet/szlcsc/Download-ISO9001-Certification.pdf - Role Details: Sensirion SDP810-500PA-D; may be external via Qwiic connector - Package or Case Code: SENSOR-TH_SDP810-500PA - JLCPCB Part Class: Extended Part - Product Info Url: https://lcsc.com/product-detail/Sensors_Sensirion_SDP810-500PA_SDP810-500PA_C153056.html - LCSC Part Number: C153056 **Pins:** - 0 [pin 0] - GND [pin 3] - SCL [pin 1] - SDA [pin 4] - VDD [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/unluckynelson/melodic-moccasin-speeder-bike](https://www.flux.ai/unluckynelson/melodic-moccasin-speeder-bike).* --- *Generated from [https://www.flux.ai/unluckynelson/melodic-moccasin-speeder-bike](https://www.flux.ai/unluckynelson/melodic-moccasin-speeder-bike)*