Day 0: The Doctor's Archive

The Doctor's Archive

The door of the old tech shop sticks, then gives. Dust, dead electronics, oil. Somewhere under the counters is an emergency kit, and hovering at your shoulder is a drone called Orion who has just told you that the Resistance needs a signal — tonight.

There is one problem, and Orion says it out loud in the very next lesson: he has no fingers. He can read every datasheet ever written and he cannot pick up a single resistor. The building, the wiring, the typing — all of that is yours.

So before Kai can send anything to anyone, the bench has to work. Dr. Ezekiel left recordings in this shop for exactly that, and this page is his archive: the firmware, the editor, and the first light. Work through it once and you never do it again.

By the time you reach the bottom of this page there will be a light blinking because you told it to — once in a simulation, and once on the real board in front of you. You do not need to have written a line of code before now. This page assumes you haven't.

Somewhere Safe to Fail

You have one Pico and no spare, so you are not going to learn on it.

Open the Circuit IDE instead. It is a full electronics bench that runs in your browser — the same parts, the same wiring, the same MicroPython — except nothing in it can be burnt out or snapped in half. Open it in a second browser tab and leave it there. You will be moving between it and these lessons constantly, and that is far easier side by side than one at a time.

Drag a Pico WH out of the Controllers group on the left onto the empty canvas, then click across to the Code tab, where a file called main.py is waiting. Select everything in it, delete it, and put this in its place:

from machine import Pin
import time

led = Pin(25, Pin.OUT)

while True:
    led.on()
    time.sleep(1)
    led.off()
    time.sleep(1)

Then press Run.

That was the simulated board's own onboard lamp, which sits on GP25. Worth knowing now rather than discovering the hard way: the Pico W in your kit wires its onboard lamp somewhere Pin(25) cannot reach, so that exact line will do nothing on real hardware. Everything physical from here uses an LED of your own on GP15 — which is the pin Orion reaches for on Day 1, and again on Day 5 when you build the intruder alarm.

Which means it is time to find that emergency kit.

The Emergency Kit

Four things, and you can leave the jumper wires in the box — Day 1 deliberately does without them.

1. The Raspberry Pi Pico W. The small board with the USB port at one end. Orion's description is the one worth keeping: an older version of him that cannot talk, but understands a language called MicroPython.
2. An LED. A small light bulb with two legs. It is polarised, which means it only works one way round — the longer leg is positive (the anode) and the shorter leg is negative (the cathode). Backwards, it simply stays dark.
3. One 220Ω resistor. A small cylinder with coloured bands, used to limit the current through the LED. If yours has five bands, 220Ω reads red, red, black, black, brown; if it has four, red, red, brown, gold. In this kit they are also grouped and labelled in brown tape — the doctor's eyesight is not what it was, so he labels everything.
4. The breadboard. The rectangular board covered in holes. It is a grid of connected sockets that lets you build and rearrange a circuit without soldering anything.

Teaching It a Language

A Pico understands MicroPython, but it does not arrive knowing it. This is the step that stalls most kits on their first evening, and it is the one nobody warns you about.

1. Download the MicroPython firmware for the Pico W. It is a file ending in .uf2 and it lands in your Downloads folder.