Minimal Pico 2 Sensor Design
Thought for 7 sec
I’ll keep this minimal: inspect the Pico 2 shield pins, select one simple I2C humidity sensor plus only required pull-ups/decoupling/power connections, wire it, then run checks and fix any issues.
Worked for 4 mins 2 sec
The sensor circuit is wired. Review found only unused Pico header pins floating plus VBUS not used on this minimal shield, so I’m marking those intentionally unconnected and re-checking.
Worked for 1 min 2 sec
VBUS is modeled as a required power input, so I’m adding one simple 2-pin 5V/GND power header rather than adding USB-C circuitry. This keeps the shield minimal and gives the Pico a defined power source in the schematic.
Worked for 2 mins 36 sec
Done — I added a minimal Pico 2 humidity-sensor shield circuit: SHTC3 sensor, 10kΩ I2C pull-ups, 100nF local decoupling, GND/3V3/I2C wiring, and a simple 2-pin 5V/GND VBUS input header.
Validation passed: electrical review now reports no ERROR/WARNING/UNCERTAIN ERC checks. I also saved the design notes and power budget in Minimal Pico 2 Humidity Sensor Shield Design Notes.
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Minimal Pico 2 Humidity Sensor Shield Design Notes
Scope
Minimal schematic additions for a Raspberry Pi Pico 2 shield:
- One Sensirion SHTC3 I2C humidity/temperature sensor.
- Required SHTC3 support components only: SDA/SCL pull-ups and local VDD decoupling.
- One simple 2-pin 5V/GND input header to satisfy the Pico 2 VBUS power input in the schematic.
Datasheet-grounded SHTC3 requirements
Source: Sensirion SHTC3 datasheet.
- Supply voltage VDD: 1.62 V to 3.6 V; operated from Pico 2 3V3.
- Pins: VDD, SCL, SDA, VSS; center/EPAD internally connected to VSS and may be connected to GND.
- Decoupling: 100 nF capacitor between VDD and VSS, placed close to the sensor.
- I2C: external pull-up resistors required on SDA and SCL; datasheet example RP = 10 kΩ.
- I2C clock: supports 0 to 1 MHz Fast Mode Plus.
Power budget
Table
| Rail | Load | Typical | Peak |
|---|---|---|---|
| 3V3 | SHTC3 average normal mode, 1 measurement/s | 4.9 uA | - |
| 3V3 | SHTC3 measurement normal mode | 430 uA | 900 uA |
Added shield sensor load on Pico 3V3: 900 uA peak. The 3V3 and VBUS net metadata use 0.001 A max current for this added load. Pico 2 board current itself depends on firmware and is supplied through the VBUS header or onboard Pico USB power path.
Connections
- U2 SHTC3 VDD -> 3V3.
- U2 SHTC3 VSS and EPAD -> GND.
- C1 100 nF -> between 3V3 and GND near U2.
- U2 SDA -> U1 GPIO4 / I2C_SDA, with R1 10 kΩ pull-up to 3V3.
- U2 SCL -> U1 GPIO5 / I2C_SCL, with R2 10 kΩ pull-up to 3V3.
- J1 Pin_1 -> VBUS, J1 Pin_2 -> GND.
Validation
Electrical review after wiring and no-connect marking reports no ERROR, WARNING, or UNCERTAIN ERC checks matching the validation filter.
Scope
Datasheet-grounded SHTC3 requirements
Power budget
Connections
Validation
