Minimal Pico 2 Humidity Sensor Design
Add the minimum required components needed for this Pi Pico 2 to function properly. Keep the design as simple and minimal as possible.
You may include a single humidity sensor as the primary peripheral, along with any essential supporting components such as power regulation, pull-up resistors, decoupling capacitors, or required connectors.
Thought for 12 sec
I’ll keep this minimal: inspect the Pico 2 shield pins, choose a simple 3.3 V I2C humidity sensor, add only required pull-ups/decoupling, wire it to the Pico 2’s existing 3V3/GND/GPIO pins, then run checks and fix any real issues.
Worked for 2 mins 44 sec
The sensor block is wired. Review found the remaining issues are unused Pico 2 shield header pins, so I’m marking unused pins intentional and tying all ground header pins together to keep the minimal schematic clean.
Worked for 1 min 44 sec
Done — I added the minimal SHTC3 humidity/temperature sensor circuit with only the required 100 nF decoupling capacitor and 10 kΩ I2C pull-ups, wired to Pico 2 GPIO4/GPIO5, 3V3, and GND.
ERC is clean with zero unresolved electrical violations. I also created Minimal Pico 2 Humidity Shield Design Notes with the pin map, datasheet rationale, and power budget.
Next step is PCB placement/layout when you’re ready.
Yes, place layout
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Minimal Pico 2 Humidity Shield Design Notes
Scope
Minimal Raspberry Pi Pico 2 shield circuitry for one primary peripheral: a Sensirion SHTC3 I2C humidity/temperature sensor.
Added Components
- U2: SHTC3-TR-2.5KS humidity/temperature sensor
- C1: 100 nF decoupling capacitor from SHTC3 VDD to GND
- R1: 10 kΩ I2C SDA pull-up to 3V3
- R2: 10 kΩ I2C SCL pull-up to 3V3
Datasheet-Grounded Requirements
From the SHTC3 datasheet:
- Supply voltage: 1.62 V to 3.6 V; connected to Pico 2 3V3.
- Pins: VDD, SCL, SDA, VSS; exposed pad internally connected to VSS/GND.
- VDD and VSS must be decoupled with 100 nF placed close to the sensor.
- I2C SDA/SCL require pull-up resistors; datasheet example uses 10 kΩ.
- I2C supports Fast Mode Plus up to 1 MHz with clock stretching.
Pin Mapping
Table
| Pico 2 Shield Pin | Net | Peripheral Pin | Purpose |
|---|---|---|---|
| U1 GPIO4 | I2C_SDA | U2 SDA | I2C data |
| U1 GPIO5 | I2C_SCL | U2 SCL | I2C clock |
| U1 3V3 | 3V3 | U2 VDD, C1 P1, R1/R2 P2 | Sensor power and pull-up rail |
| U1 GND/AGND pins | GND | U2 VSS/EPAD, C1 P2 | Return path |
Power Budget
Only the SHTC3 load is added to the Pico 2 shield.
Table
| Rail | Component | Typical | Worst-case / peak |
|---|---|---|---|
| 3V3 | SHTC3 measurement current | 430 µA | 900 µA |
| 3V3 | I2C pull-ups | Dynamic only | Depends on bus activity; 10 kΩ limits each low line to about 330 µA at 3.3 V |
Total added continuous sensor current is under 1 mA. The Pico 2 onboard 3V3 rail is suitable for this minimal peripheral load.
Firmware Bring-Up Notes
Use I2C0 on Pico 2 with SDA=GPIO4 and SCL=GPIO5. Configure pull-ups externally are already present in hardware, so internal pulls are optional/off. The SHTC3 driver should support clock stretching and wake/sleep command sequences per Sensirion's protocol.
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