Minimal Pico 2 Humidity Sensor Design
Thought for 4 sec
I’ll turn this Pico 2 shield template into a minimal working humidity-sensor shield: first I’ll inspect the existing Pico header part, then select a simple I2C humidity sensor and only the required support parts, wire power/I2C/decoupling, and run checks.
Worked for 1 min 30 sec
I found the Pico 2 shield exposes 3V3/GND and GPIO pins, so I’m using the Pico’s onboard 3.3 V rail—no extra regulator is needed. I selected an SHTC3 I2C humidity/temperature sensor; its datasheet requires only a 100 nF decoupling capacitor and SDA/SCL pull-ups.
Worked for 4 mins 23 sec
Done — I added the minimal SHTC3 humidity/temperature sensor circuit for the Pico 2 shield: SHTC3 on I2C0 using GPIO0/GPIO1, 10 kΩ SDA/SCL pull-ups, and a 100 nF local decoupling capacitor on 3V3. Schematic ERC/manufacturing/passive checks are clean; full review still shows PCB airwires because layout/routing has not been done yet.
I also recorded the design rationale in Minimal Pico 2 Humidity Shield Notes. The next step is layout placement for the new sensor and passives, then routing.
Proceed to layout
Use compact placement
Prioritize sensor exposure
Add firmware notes
Review BOM
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Minimal Pico 2 Humidity Shield Notes
Scope
Add the minimum required schematic components for a Raspberry Pi Pico 2 shield to support one humidity sensor peripheral.
Selected peripheral
- Sensor: Sensirion SHTC3-TR-2.5KS humidity and temperature sensor
- Interface: I2C Fast Mode Plus capable
- I2C address: 0x70
- Supply range: 1.62 V to 3.6 V
- Typical/maximum measurement current from datasheet: 430 uA typical, 900 uA maximum in normal measurement mode
Power approach
The shield uses the Pico 2 3V3 pin as the sensor rail. No additional regulator is required because the SHTC3 operates from 1.62 V to 3.6 V and the sensor load is under 1 mA peak.
Schematic connections
- U2 SHTC3 VDD -> 3V3
- U2 SHTC3 VSS and EPAD -> GND
- U2 SHTC3 SDA -> Pico GPIO0 / I2C0_SDA
- U2 SHTC3 SCL -> Pico GPIO1 / I2C0_SCL
- C1 100 nF -> between 3V3 and GND close to U2
- R1 10 kOhm -> SDA pull-up to 3V3
- R2 10 kOhm -> SCL pull-up to 3V3
Supporting components
- C1: 100 nF, 25 V, 0603 ceramic decoupling capacitor; selected MPN GRM188R71E104KA01D
- R1/R2: 10 kOhm, 1%, 0603 pull-up resistors; selected MPN RC0603FR-0710KL
Validation notes
The schematic-level ERC and manufacturing checks are clean after wiring and adding passive MPN metadata. Full project review still reports PCB airwires because the new schematic nets have not been placed/routed on the PCB yet; this is expected until the user approves moving from schematic to layout.
Scope
Selected peripheral
Power approach
Schematic connections
Supporting components
Validation notes
