Minimal Pi Pico 2 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 11 sec

flux

I’ll keep this minimal: inspect the Pico shield pins, choose a simple I2C humidity sensor, add only its required pull-ups/decoupling, then wire and run checks.

Worked for 3 mins 25 sec

flux

Schematic wiring is complete; I’m cleaning up ERC noise from the unused Pico shield pins and documenting the minimal design decisions.

Worked for 4 mins 41 sec

flux

Done — I added the minimal Pico 2 humidity shield circuitry: SHT40 sensor, 10kΩ SDA/SCL pull-ups, 100nF sensor decoupling, and a simple 2-pin 5V/GND VBUS power header.

The schematic ERC is clean for the added circuit; remaining review errors are PCB airwires only, which are expected because the new components have not been placed/routed yet. I also recorded the design rationale in Minimal Pico 2 Humidity Shield Notes.

Move to layout

Keep schematic only

Remove power header

Add firmware notes

Review component values

Files

Schematic

Layout

3D View

U1 VBUS - J1 P1

GND

U1 3V3 - U2 VDD

U1 VBUS - J1 P1

U1 3V3 - U2 VDD

U1 GPIO5 - U2 SCL

U1 GPIO4 - U2 SDA

GND

U1 GPIO5 - U2 SCL

U1 3V3 - U2 VDD

U1 GPIO4 - U2 SDA

U1 3V3 - U2 VDD

GND

U1 3V3 - U2 VDD

U1 GPIO5 - U2 SCL

GND

U1 GPIO4 - U2 SDA

Resistance

10000 Ω

Resistance

10000 Ω

Capacitance

100 nF

Minimal Pico 2 Humidity Shield Notes

Goal

Keep the Raspberry Pi Pico 2 shield design as simple as possible while adding one primary peripheral: an I2C humidity/temperature sensor.

Selected Sensor

U2: Sensirion SHT40-AD1F-R2
Interface: I2C
I2C address: 0x44
Supply: 1.08 V to 3.6 V; used at Pico 2 3V3
Datasheet typical application: SDA/SCL each have a 10 kΩ pull-up to VDD, and VDD has a 100 nF decoupling capacitor to VSS/GND.

Connections

Table

Net	Pico 2 Shield Pin	Sensor / Support Connections
`VBUS_5V_IN`	U1 VBUS pin 40	J1 P1 external 5 V input
`3V3`	U1 pin 36	U2 VDD, R1 P2, R2 P2, C1 P1
`GND`	All U1 GND pins and AGND	U2 VSS, C1 P2, J1 P2
`I2C0_SDA`	U1 GPIO4 pin 6	U2 SDA, R1 P1
`I2C0_SCL`	U1 GPIO5 pin 7	U2 SCL, R2 P1

Supporting Components

J1: 2-pin 2.54 mm power header for optional external 5 V/GND input to Pico 2 VBUS
R1: 10 kΩ I2C SDA pull-up to 3V3
R2: 10 kΩ I2C SCL pull-up to 3V3
C1: 100 nF local decoupling capacitor from SHT40 VDD to GND

Power Budget

No additional regulator is required because this shield uses the Pico 2 module's onboard 3.3 V rail. The SHT40 load is very small compared with the Pico 2 3V3 rail capability. J1 provides a minimal explicit 5 V/GND input option for the Pico 2 VBUS pin; alternatively, if the physical Pico 2 module is powered via its onboard USB connector, J1 can be left unpopulated.

Minimality Decisions

No separate regulator was added.
One 2-pin power header was added only to give the Pico 2 VBUS input an explicit external power entry in this shield schematic.
Unused Pico 2 shield pins were marked as intentionally unused for this minimal variant.
PCB routing/placement DRC airwires are expected until the user approves moving from schematic to PCB layout.

Goal
Selected Sensor
Connections
Supporting Components
Power Budget
Minimality Decisions