Make me a temperature and humidity sensor node wit
Working for 2 days 7 hrs...
Thought for 8 sec
Found 10 results for Espressif ESP32-C3-MINI-1 datasheet pdf.
Found 10 results for Sensirion SHT4x datasheet pdf.
Found 10 results for Texas Instruments TPS25947 datasheet pdf.
Found 10 results for Texas Instruments TLV75733 datasheet pdf.
Found 10 results for ST USBLC6-2SC6 datasheet pdf.
Thought for 5 sec — Considering library improvements
Found 10 results for ESP32-C3-MINI-1.
Found 1 results for SHT40-AD1B-R3.
Found 10 results for TPS25947.
Found 10 results for TLV75733PDBVR.
Found 8 results for USBLC6-2SC6.
Found 3 results for USB Type-C receptacle for USB 2.0 device power input, 16-pin or similar, 5V sink, board-mount consumer product.
Thought for 8 sec — Consulting datasheets for parts
Read ESP32-C3-MINI-1-N4 datasheet for pin configuration.
Read ESP32-C3-MINI-1-N4 datasheet for power supply scheme.
Read ESP32-C3-MINI-1-N4 datasheet for strapping pins and usb interface.
Read SHT40-AD1B-R3 datasheet for pin assignment.
Read SHT40-AD1B-R3 datasheet for typical application circuit.
Read SHT40-AD1B-R3 datasheet for i2c address and supply current.
Read TPS259474LRPWR datasheet for features and protection functions.
Read TPS259474LRPWR datasheet for functional block and pin functions.
Read TPS259474LRPWR datasheet for typical application circuit uvlo ovp cur.
Read TLV75733PDBVR datasheet for recommended application circuit.
Read TLV75733PDBVR datasheet for input output capacitor requirements.
Read TLV75733PDBVR datasheet for dropout quiescent current and enable pin.
Read USBLC6-2SC6 datasheet for pin configuration and usb 2.0 protection.
Thought for 10 sec — Searching for datasheets
No results for resettable fuse polyfuse 1A 16V flux library site:flux.ai/search.
Reading "pin configuration and typical USB 2.0 connection" in usblc6-2.pdf.
Reading "features reverse current blocking overvoltage protection undervoltage lockout current limit and input voltage range" in tps25947.pdf.
Reading "pin functions and typical application circuit" in tps25947.pdf.
Reading "equations or resistor selection for UVLO OVLO current limit and dvdt" in tps25947.pdf.
Read usblc6-2.pdf.
Read tps25947.pdf.
Read tps25947.pdf.
Read tps25947.pdf.
Thought for 17 sec — Searching for components
Reading "PGTH pin behavior if unused and PG open drain pull-up requirements" in tps25947.pdf.
Reading "ITIMER and dVdt can be left open if unused" in tps25947.pdf.
Reading "recommended values for CIN and COUT or input output capacitors" in tps25947.pdf.
Read tps25947.pdf.
Read tps25947.pdf.
Read tps25947.pdf.
Thought for 11 sec — Planning component selection
Found 2 results for SMF5.0A TVS diode.
Found 2 results for ESD5Z5.0 TVS diode.
Found 10 results for PESD5V.
No results for tactile switch 2 pin smd pushbutton.
Thought for a moment — Searching for VBUS solutions
Read PESD5V0S1BA,115 datasheet for reverse standoff voltage and clamp volta.
Read PESD5V0S1BA,115 datasheet for typical connection for 5V line to ground.
Found 3 results for small SMD momentary tactile pushbutton switch for BOOT and RESET buttons on an embedded PCB, normally open, top-actuated, compact consumer electronics.
Thought for 4 sec — Evaluating component selection
Read SMF5.0A datasheet for reverse standoff voltage and peak pulse .
Read SMF5.0A datasheet for pin polarity cathode anode and unidirect.
Thought for 11 sec — Searching for datasheet
Reading "Table pin definitions" in usblc6-2.pdf.
Reading "Application schematic for USB data lines D+ D- VBUS GND" in usblc6-2.pdf.
Reading "Very low capacitance ESD protection USB 2.0 pinout I O1 I O2 GND VBUS" in usblc6-2.pdf.
Read usblc6-2.pdf.
Read usblc6-2.pdf.
Read usblc6-2.pdf.
Thought for 13 sec — Considering GPIO setup
Ran calculation.
Ran calculation.
Ran calculation.
Ran calculation.
Ran calculation.
Thinking...
Writing design notes
I need to write design notes that include component selections and the power budget, probably later. I should also add components. First, I want to get property config for a generic package, which might involve querying options for that package. Maybe I could skip including specifics like resistance or capacitance for now. I’ll try omitting the designator and see if it returns standard options that cover multiple choices.
Evaluating capacitor needs
I’m considering the capacitor requirements for my project. For C1, I’ll use a 1uF eFuse CIN. For C2, a 10uF eFuse COUT sounds good, and maybe I should stick with that. C3 will have a 1uF for LDO input.
Evaluating capacitor needs...
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Project Specification
Project Overview
USB-C powered low-power consumer environmental sensor node with integrated 2.4 GHz Wi-Fi (802.11 b/g/n) and Bluetooth Low Energy 5.x. The node measures ambient temperature and relative humidity using a digital sensor and is intended for fixed 5 V USB-C powered deployment.
Requirements
- USB-C receptacle input, sink/device role, default 5 V operation only
- Operates from USB-C sources advertising default current up to 3 A without USB PD negotiation
- Include input protection strategy covering reverse current/blocking behavior, over-voltage protection, under-voltage lockout, and over-current limiting/protection considerations
- Low-power Wi-Fi + BLE capable MCU/module
- Digital temperature/relative humidity sensor on a low-power digital bus
- 3.3 V system rail for MCU and sensor
- Consumer-oriented design with simple programming/debug access over USB
Architecture
- MCU/Radio: ESP32-C3-MINI-1 module (single-chip MCU + 2.4 GHz Wi-Fi + BLE 5, native USB, low-power capable, module avoids custom RF design)
- Sensor: Sensirion SHT40 digital temperature/relative humidity sensor on I2C
- USB-C power entry: USB-C receptacle configured as a sink using dual 5.1 kΩ CC pull-down resistors
- Input protection path: USB VBUS -> resettable fuse / current limiter stage -> surge/ESD protection -> reverse-blocking / ideal-diode style power-path controller stage with UVLO/OVLO control -> 3.3 V regulator
- Main regulator: 3.3 V low-IQ LDO sized for ESP32-C3 Wi-Fi burst current with appropriate thermal margin
- Programming/debug: Native USB D+/D- routed to ESP32-C3 USB pins with ESD protection
- User interface: power/status LED optional; keep base design minimal and low-power
Preliminary Power Budget
Assumptions for sizing:
- ESP32-C3 average active current: tens of mA, with Wi-Fi TX/RX bursts well above 300 mA
- Design peak budget target on 3.3 V rail: >= 500 mA
- SHT40 current is negligible relative to radio load
- USB-C source may be capable of 0.5 A to 3 A; design input path should safely accept compliant 5 V sources across that range without drawing more than required by the load
Why 3.3 V LDO is acceptable:
- 5 V to 3.3 V drop is 1.7 V
- At 300 mA average heavy activity, dissipation is about 0.51 W, which is manageable only with an adequately rated package and copper area
- At burst conditions the average thermal load remains much lower than peak instantaneous current, but regulator transient response and output capacitance must support radio current pulses
Protection Intent
- Reverse / backfeed protection: prevent system rail from driving current back into VBUS when unplugged or faulted
- OVP / surge protection: clamp ESD/transients on VBUS and USB data lines; add front-end device with input over-voltage protection or controlled cutoff if supported by chosen part
- UVLO: avoid brownout operation from drooping VBUS/cable conditions by selecting front-end device or regulator enable thresholding
- OCP: fuse/current-limiter stage sized from the system power budget; protect against shorts while tolerating inrush and radio burst current
Key Nets Planned
- VBUS_RAW
- VBUS_PROTECTED
- 3V3
- GND
- USB_D+
- USB_D-
- USB_CC1
- USB_CC2
- I2C_SCL
- I2C_SDA
- EN
- GPIO9_BOOT (or equivalent boot pin net)
Open Implementation Notes
- Prefer module-based ESP32 design to simplify RF compliance and antenna matching
- Keep ESP32 antenna region free of copper/components in layout
- One pair of I2C pull-ups for the whole bus
- Native USB avoids external USB-UART bridge and reduces standby current
- Verify all selected protection parts against 5 V-only USB-C sink use case and consumer BOM availability
Project Overview
Requirements
Architecture
Preliminary Power Budget
Protection Intent
Key Nets Planned
Open Implementation Notes
