# General Cyan Lightcycle ## Description Low-Power USB-C Temperature & Humidity Sensor Node with Wi-Fi and BLE ## Project Details - **Owner:** jjspamaill - **Created:** 1/23/2026 - **Last Updated:** 1/23/2026 - **Visibility:** Public - **System Architecture:** ```mermaid flowchart TD M["Wi-Fi/BLE MCU Module"] S["I2C Temperature/Humidity Sensor"] U["USB-C Input\nwith Protection"] E["eFuse\nProtection"] B["3.3V\nBuck Regulator"] C["Connectors"] T["Test Points"] M --> S U --> E --> B --> M B --> S M --> C B --> T S --> T ``` - **Operating Voltage:** 3.3V - **Domain:** Consumer Electronics - **Software:** Bare metal - **Connectivity:** WiFi - **Power Requirements:** USB ## Key Components ### D1 — [USBLC6-4SC6](https://www.flux.ai/kicad-part-library/usblc6-4sc6.md) - Package: SOT-23-6 - Package or Case Code: SOT-23-6 - Datasheet URL: https://www.st.com/resource/en/datasheet/usblc6-4.pdf - Manufacturer Name: Texas Instruments Inc. - Manufacturer Part Number: USBLC6-4SC6 - Operating Voltage: 5V - Role: Protection - Role Details: ESD/TVS diode array for USB D+, D-, and CC lines **Pins:** - GND [pin 2] - I/O1 [pin 1] - I/O2 [pin 3] - I/O3 [pin 4] - I/O4 [pin 6] - VBUS [pin 5] ### D2 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric.md) - Role Details: Status indicator for system operation - Package: SMD_0805_2012Metric - Part Type: LED - Role: LED - Operating Voltage: 3.3V **Pins:** - A [pin 2] - K [pin 1] ### J2 — [Pin Header 01x04 2.54mm Vertical without Designators](https://www.flux.ai/markwuflux/pin-header-01x04-2p54mm-vertical-without-designators.md) - Part Type: Connector - Role Details: UART programming header (TXD, RXD, GND, 3V3 interface) - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 1] - Pin_3 [pin 3] - Pin_4 [pin 4] ### SW1 — [Tactile Switch SPST-NO PTS526 SK15 SMTR2 LFS](https://www.flux.ai/collinsemasi/tactile-switch-spst-no-pts526-sk15-smtr2-lfs.md) - Package: SMD - Role: Debouncing - Datasheet URL: https://www.ckswitches.com/media/2780/pts526.pdf - Part Type: Switch - Role Details: Boot button for part U1, pin IO0 (BOOT) - Manufacturer Name: C&K - Manufacturer Part Number: PTS526 SK15 SMTR2 LFS **Pins:** - 2 [pin 2] - 4 [pin 4] - 1 [pin 1] - 3 [pin 3] ### SW2 — [Tactile Switch SPST-NO PTS526 SK15 SMTR2 LFS](https://www.flux.ai/collinsemasi/tactile-switch-spst-no-pts526-sk15-smtr2-lfs.md) - Role Details: Reset button for part U1, pin EN (RESET) - Package: SMD - Datasheet URL: https://www.ckswitches.com/media/2780/pts526.pdf - Part Type: Switch - Manufacturer Part Number: PTS526 SK15 SMTR2 LFS - Manufacturer Name: C&K - Role: Debouncing **Pins:** - 2 [pin 2] - 4 [pin 4] - 1 [pin 1] - 3 [pin 3] ### U1 — [ESP32-C3-WROOM-02-N4](https://www.flux.ai/vasy_skral/esp32-c3-wroom-02-n4.md) - Operating Voltage: 3.3V - Role Details: Wi-Fi/BLE MCU Module - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32-c3-wroom-02_datasheet_en.pdf - Symbol Style: Parametric - Manufacturer Part Number: ESP32-C3-WROOM-02-N4 - Role: Main MCU - Manufacturer Name: Espressif Systems - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Module **Pins:** - 3V3 [pin 1] - EN [pin 2] - GND [pin 38] - GND [pin 32] - GND [pin 37] - GND [pin 22] - GND [pin 19] - GND [pin 34] - GND [pin 31] - GND [pin 21] - GND [pin 39] - GND [pin 36] - GND [pin 9] - GND [pin 25] - GND [pin 33] - GND [pin 29] - GND [pin 30] - GND [pin 28] - GND [pin 20] - GND [pin 35] - GND [pin 26] - GND [pin 24] - GND [pin 23] - GND [pin 27] - IO0 [pin 18] - IO1 [pin 17] - IO10 [pin 10] - IO18 [pin 13] - IO19 [pin 14] - IO2 [pin 16] - IO3 [pin 15] - IO4 [pin 3] - IO5 [pin 4] - IO6 [pin 5] - IO7 [pin 6] - IO8 [pin 7] - IO9 [pin 8] - RXD [pin 11] - TXD [pin 12] ### U2 — [SI7021-A20-GM1](https://www.flux.ai/adrian95/si7021-a20-gm1.md) - Datasheet URL: https://download.mikroe.com/documents/datasheets/Si7021-A20_datasheet.pdf - Manufacturer Name: Silicon Labs - Role Details: Digital I2C temperature/humidity sensor - Role: Sensor - Operating Voltage: 3.3V - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: SI7021-A20-GM1 **Pins:** - DNC [pin 3] - DNC [pin 4] - GND [pin 2] - SCL [pin 6] - SDA [pin 1] - VDD [pin 5] ### U3 — [TPS25210LRPWR](https://www.flux.ai/adrian95/tps25210lrpwr.md) - Datasheet URL: https://www.ti.com/lit/ds/symlink/tps2521.pdf?ts=1625110620252&ref_url=https%253A%252F%252Fwww.ti.com%252Fstore%252Fti%252Fen%252Fp%252Fproduct%252F%253Fp%253DTPS25210LRPWR - Role Details: eFuse for reverse polarity, OVP, UVLO, and OCP protection on USB-C input - Operating Voltage: 5V - Role: Protection - Package or Case Code: TPS25210LRPWR - Part Type: Power Management - Manufacturer Part Number: TPS25210LRPWR - Manufacturer Name: Texas Instruments - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - DVDT_1 [pin 7] - DVDT_2 [pin 14] - EN/UVLO_1 [pin 1] - EN/UVLO_2 [pin 12] - GND [pin 8] - ILM [pin 9] - IN [pin 5] - ITIMER_1 [pin 10] - ITIMER_2 [pin 11] - OUT [pin 6] - OVCSEL [pin 2] - PG [pin 3] - PGTH_1 [pin 4] - PGTH_2 [pin 13] ### U4 — [LM5164DDA](https://www.flux.ai/kicad-part-library/lm5164dda.md) - Package: HSOP-8 - Datasheet URL: https://www.ti.com/lit/ds/symlink/lm5164.pdf?ts=1598311864250&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM5164%253FHQS%253DTI-null-null-octopart-df-pf-null-wwe - Manufacturer Part Number: LM5164DDA - Operating Voltage: 5V - Role: Power Conversion - Role Details: Buck converter for 3.3 V rail - Package or Case Code: HSOP-8-1EP_3.9x4.9mm_P1.27mm_EP2.41x3.1mm_ThermalVias - Manufacturer Name: Texas Instruments Inc. **Pins:** - BST [pin 7] - EN/UVLO [pin 3] - EP [pin 9] - FB [pin 5] - GND [pin 1] - PGOOD [pin 6] - RON [pin 4] - SW [pin 8] - VIN [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/jjspamaill/general-cyan-lightcycle](https://www.flux.ai/jjspamaill/general-cyan-lightcycle).* --- *Generated from [https://www.flux.ai/jjspamaill/general-cyan-lightcycle](https://www.flux.ai/jjspamaill/general-cyan-lightcycle)*