Power & Wiring

Most event-day hardware problems are power problems before they are code problems. Use this page as the shared baseline for regulators, motor drivers, servos, and fast bring-up checks.

Official References

Start Small

Prove one powered subsystem at a time.
Get clean logic power first, then add radios, sensors, and only then motor or servo loads.
Avoid building the full machine before you have tested the power path under load.

Pico Board Power Facts

The Pico datasheet is worth knowing before you start improvising rails:

VSYS is the main system input and the board datasheet places it in the 1.8V to 5.5V range.
3V3 is the regulated 3.3V rail. Raspberry Pi recommends keeping external load on this pin below 300mA.
Pulling 3V3_EN low disables the 3.3V rail and powers the board down.
ADC_VREF and AGND matter if you want cleaner analogue measurements.

Regulator Basics

Set adjustable regulators before connecting sensitive electronics.
Re-check voltage with a meter after any wiring change.
Do not assume one regulator setting is correct for every board in the system.
If a board is resetting or acting randomly, inspect the supply rail before you change code.

LM2596 Notes

The TI LM2596 is a buck regulator, not a magic universal power fix:

official input range: 4.5V to 40V
rated output current: up to 3A
use it to step down to a target rail, then verify the actual output before you connect Pico boards, radios, or sensors

Motors and Drivers

Do not drive motors directly from the microcontroller.
Use the correct driver for the load and keep logic or control wiring separate from higher-current motor paths where practical.
Expect noise, voltage sag, and brownouts once motors start moving.

Driver-Specific Notes

The ST L298 is a dual full-bridge driver intended for inductive loads such as DC motors and steppers. It has separate logic and motor supply considerations, so wire it deliberately rather than assuming the Pico can share every rail blindly.
The Pololu DRV8825 carrier supports simple step-and-direction control, adjustable current limiting, up to 45V motor supply, and direct 3.3V logic interfacing. Set the current limit before you expect a stepper setup to behave.

Servo and High-Load Notes

Treat larger servos and launch or drive actuators as separate load problems, not as simple accessories.
If motion becomes erratic under load, suspect supply stability, grounding, or current draw first.

Wiring Habits That Save Time

label or write down final pin assignments
keep ground routing obvious
test continuity when something looks right but behaves wrong
change one thing at a time when debugging

When to Stop and Ask

Ask a supervisor if:

you are not sure a board should be powered from a given rail
the regulator setting is uncertain
wires or drivers are getting hot
the system works on USB but fails on its intended power source