Temperature and Humidity Sensor Design

Make me a temperature and humidity sensor node with Wifi and Bluetooth, powered by USB-C (5V) for consumer use.

It should be a low-power environmental node with a digital T/RH sensor, ultra-low-power MCU with Wi-Fi + Bluetooth (dual-radio) — 2.4 GHz 802.11 b/g/n plus BLE 5.x powered by USB-C (5 V) — USB-C receptacle 5 V default; include reverse/OVP/UVLO/OCP protection and plan for 0.5–3 A sources.

6 days

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Plan

#Goal

Design a consumer-grade, USB-C powered, low-power environmental sensor node that measures temperature and humidity using a digital sensor and communicates over dual-radio Wi-Fi (802.11 b/g/n) and Bluetooth (BLE 5.x). The design must include protection for USB-C inputs (reverse polarity, OVP, UVLO, and OCP) supporting 0.5–3 A sources.

#Implementation plan

Define System Architecture and Update Project Metadata
1. Update the project description to capture the environmental sensing goal, dual-radio connectivity, and USB-C power input with protection features.
Select and Add Core Components
1. Add a digital temperature/relative humidity sensor from the parts library (e.g., Si7021 or similar).
2. Select and add an ultra-low-power MCU with integrated Wi-Fi and Bluetooth dual-radio (e.g., an ESP32 variant that supports 802.11 b/g/n and BLE 5.x).
Design the Power and USB-C Protection Subsystem
1. Add a USB-C receptacle designed for 5 V input.
2. Incorporate protection circuitry including reverse polarity, over-voltage (OVP), under-voltage lockout (UVLO), and over-current (OCP) support that can handle between 0.5–3 A.
3. Implement a 3.3 V regulator (buck converter or LDO, as appropriate) for powering the MCU and sensor.
Integrate and Connect Supporting Components
1. Add necessary decoupling capacitors, resistors, and any filtering components for stable operation of the sensor and MCU.
2. Create and connect the I2C (or relevant digital interface) nets between the MCU and the temperature/humidity sensor.
3. Include programming/debug access connectors for firmware updates and testing.
Develop Schematic and Electrical Review
1. Wire and label all nets, ensuring proper current paths and protection integrations.
2. Perform an ERC and design review to verify circuit integrity and compliance with the consumer-grade requirements.
Prepare PCB Layout
1. Set up an appropriate board stackup and size, ensuring that layout guidelines for RF (Wi-Fi/BLE) are followed, including edge placement for the antenna and suitable keepouts.
2. Position the sensor area for reliable environmental exposure and group the power-path for minimal interference.
Finalize Documentation
1. Produce comprehensive project documentation covering system architecture, power/current assumptions, and protection behavior.
2. Include firmware starter documentation to illustrate sensor reading and dual radio usage.

#Success criteria

The schematic includes a USB-C power input with reverse/OVP/UVLO/OCP protection, correct voltage regulation, and proper interfacing of the digital temperature/humidity sensor with the ultra-low-power dual-radio MCU.
The PCB layout meets consumer-grade requirements with correct stackup, component placement (especially the RF antenna region), and proper thermal/environmental sensor exposure.
Complete documentation is provided detailing design decisions, electrical specifications, and firmware development guidelines.

Add USB-C ESD

Choose ESP32-C3

Compact board target

Add LED buttons

Hand-solderable parts

6 days

Reviews

Ground
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