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Purchasing Guide for the Moving Rainbow Base Kit

The Moving Rainbow base kit with the Pico, breadboard and LED strip assembled

The base kit is a Raspberry Pi Pico driving a 30-pixel WS2812B LED strip, with two push buttons for changing patterns. It is the kit every lesson in this book is written against. One kit costs about \(13** if you buy the parts individually; a classroom order of 20 brings that down to about **\)9.65 per student, which is where most teachers land. Buying direct from China saves roughly 40% on everything except the Pico, at the cost of 2–3 weeks of shipping — so order a semester ahead if you can.

Prices checked August 2026

Component prices move, and marketplace listings turn over constantly. Treat every figure here as a planning estimate, not a quote. The search links below always show current pricing.

Summary of Parts List

Required

Optional

Estimated total: ~\(13 for one kit · ~\)9.65 per student for a class of 20

Raspberry Pi Pico

Raspberry Pi Pico microcontroller board

The Pico is the microcontroller at the heart of this project. It runs MicroPython, drives all 30 pixels from a single GPIO pin, and reads both buttons. The kit's configuration uses GPIO 0 for the strip data line and GPIO 15 and GPIO 14 for the two buttons.

We always buy our Picos at Micro Center, which faithfully sells them for $3.99 USD — we have seen them on sale for $2.99. No marketplace beats that, so this is the one part where the usual order-from-China logic does not apply.

Two things to get right when ordering. First, boards ship without headers unless the listing says "H" or "with headers" — a bare Pico needs about five minutes of soldering before it will seat in a breadboard, so buy the "H" variant for classroom kits. Second, the "W" variant adds WiFi for about $6; none of the base lessons need it.

Prep work: None if you buy the "H" (pre-soldered header) variant. A bare board needs 40 header pins soldered, roughly 5 minutes each with practice.

Cost: $3.99 each at Micro Center · $3.99 each at any quantity — Micro Center does not discount further, but at that price it does not need to. Expect $4–6 elsewhere.

Search keywords: Raspberry Pi Pico, Raspberry Pi Pico H (headers pre-soldered), Raspberry Pi Pico 2, RP2040. Note that marketplace listings are frequently clones — fine for classroom use, but order one and check it before committing to twenty.

Where to buy:

Solderless Breadboard

Half-size 400 tie point solderless breadboard

We only use the 1/2-size 400-tie-point breadboards. They have exactly enough room for the Pico and two buttons, which is all this kit needs, and they cost noticeably less than the 830-point full-size boards. We buy them on eBay in packs of 10 or 20 to keep the cost down.

Prep work: We use a permanent marker to mark the rails before handing kits out — black for the GND pins, red for the power pins, and yellow for the data pin that goes to GPIO 0 on row 1. It takes about two minutes per board and eliminates an entire category of wiring mistakes.

Breadboard with GND, power and data rails marked in permanent marker

Here is how we place the Pico on the breadboard. Note that the USB connector is at the top, so GPIO 0 (pin 1) is on row 1. The 5V connection is on VBUS, and the black wire can go to any GND row.

Pico seated on a marked breadboard with the LED strip attached

Cost: ~\(2–4 each in quantity 1 · ~\)1.50 each in packs of 10 or 20. This part has one of the steepest pack discounts in the kit, so buy the pack.

Search keywords: 400 tie point breadboard, half size solderless breadboard, mini breadboard 400 points. Avoid MB-102 — that is the 830-point full-size board.

Where to buy:

Addressable LED Strip

WS2812B LED strip at 60 pixels per meter

This is the part that makes the kit worth building — a chain of WS2812B "addressable" pixels, each holding a red, green and blue LED plus a small controller that reads its own color off the data line and passes the rest along. That chaining is why 30 pixels need only one GPIO pin.

We buy 1-meter strips at 60 pixels per meter and cut each one in half, so one strip yields two kits. Two specifications matter when comparing listings. Buy the 5V version: the 12V WS2815 looks identical in listing photos and will not run from the Pico's VBUS pin. And buy IP20 (uncoated) for indoor classroom use — IP65 silicone coating is worth it for take-home projects and costumes, but it makes soldering harder.

Prep work: Cut the strip at the 30-pixel mark, following the copper pad line.

Where to cut the 1-meter strip at the 30-pixel halfway point

Solder wire to the three pads at the input end. Budget about 10 minutes per strip.

Wires soldered to the pads at the strip's cut end

We solder 22-gauge solid-core wire to the ends of the strip's stranded leads, because stranded wire will not seat in a breadboard tie point.

22-gauge solid core wire soldered onto the stranded strip leads

Then we slide colored heat shrink over each joint and shrink it. This strain-relieves the connection — WS2812B pads lift easily — and color-codes power, ground and data so students wire the strip correctly without tracing.

Heat gun shrinking colored tubing over the soldered wire joints

Cost: ~\(3–6 per meter from eBay or AliExpress, so ~\)2.50 per kit · ~\(3 per meter in a classroom order direct from China, so ~\)1.50 per kit. The same strip runs $10–15 per meter on Amazon. This is the part where ordering ahead saves the most money.

Search keywords: WS2812B LED strip 60 LED/m 5V, addressable RGB LED strip, WS2812B IP20 1m. Be aware that "NeoPixel" is Adafruit's brand name for this part — searching it returns Adafruit product at several times the price for an electrically identical strip.

Where to buy:

Momentary Push Buttons

Momentary push button (6mm tactile switch) with four leads

Our kits have two of these buttons so students can change the mode of the kit. The normal arrangement is one pattern per mode, with the buttons moving the mode selection forward or backward. Advanced students can use the second button to change a setting within a mode, or attempt a double-click to change a parameter — which is genuinely hard and makes a good extension challenge. The kit configuration reads them on GPIO 15 and GPIO 14.

Buy the 6mm × 6mm four-pin tactile type. Its leads straddle the breadboard's center channel as shipped, which is why no prep work is needed.

Tactile switch seated across the center channel of a breadboard

One thing worth telling students before they wire: the four pins are two pairs that are internally connected. Wiring across the wrong pair makes the button look permanently pressed, and it is the most common debugging session of the whole unit.

Colored caps are a cheap addition that makes the two mode buttons visually distinct, which helps a lot when a student is explaining their project to someone else.

Assorted colored caps for tactile switches

Prep work: None — it is breadboard-ready as shipped.

Cost: ~$0.10–0.25 each in quantity 1 · effectively free in a classroom order, since packs of 100 run $5–10 and a class of 20 needs only 40.

Search keywords: 6x6mm tactile push button switch, momentary tactile switch 4 pin breadboard, tactile switch caps 6x6mm. The larger 12x12mm tactile switch with cap is easier for younger students to press.

Where to buy:

Jumper Wires

22-gauge solid core wires cut to length for breadboard use

We use 22-gauge solid-core jumper wires, custom cut to length, rather than the pre-made Dupont bundles. Cut-to-length wires lie flat against the board, so students can actually see the circuit they built instead of a nest of loops. Each kit uses three black ground wires and two colored wires connecting each button to GND.

Solid core is not a preference here: stranded wire frays at the tip and will not enter a breadboard tie point.

Prep work: Cut to length and strip about 1/4 inch from each end. Figure 10–15 minutes to cut a full set for one kit, which makes this a good task for a prep session with volunteers.

Cost: ~\(8–15 for a multi-color spool set in quantity 1 · one spool set serves an entire classroom, so budget it per classroom (~\)12), not per student.

Search keywords: 22 AWG solid core hookup wire kit, 22 gauge solid wire breadboard, hookup wire spool set 6 colors. Do not search for "jumper wires" alone — that mostly returns pre-made stranded Dupont bundles.

Where to buy:

Micro USB Data Cable

Micro USB connector

The cable both programs the Pico from Thonny and powers the strip during lessons, so every student needs one at their station. The original Pico and the Pico 2 use micro-USB; some clone boards use USB-C, so confirm the connector on the board you actually ordered.

The failure worth warning teachers about: many cheap micro-USB cables are charge-only and carry no data lines. A charge-only cable powers the board perfectly while making it completely invisible to Thonny, which looks exactly like a dead board. Buy cables explicitly listed as data or sync cables, and keep one known-good cable aside for debugging.

Prep work: None. Label them if your students share a cart — cables migrate.

Cost: ~\(2–3 each in quantity 1 · ~\)1.50 each in multi-packs of 5 or 10. Many classrooms already have a drawer of these, so check before ordering.

Search keywords: micro USB data cable, micro USB sync cable 3ft, USB A to micro B data cable. The words "data" or "sync" in the listing are what separate a working cable from a charge-only one.

Where to buy:

Three-Screw Terminal Header

Three-terminal screw header

Some of our kits are designed to let students quickly attach different types of NeoPixel strips or NeoPixel rings and keep them connected even when the kit is thrown into a school backpack. We use a three-terminal screw header for those kits.

Screw header sitting next to a breadboard for scale

The specification people get wrong is the pitch. Buy 5.08mm pitch, which sits cleanly next to a breadboard; 3.5mm terminals are also common and will not line up the same way.

Prep work: Solder short 22-gauge solid-core leads to the header's pins so it seats in the breadboard. About 5 minutes each. The payoff is that the strip's stranded wire clamps into the screw terminals with no soldering at all, so students can swap strips themselves.

Cost: ~\(0.30–0.80 each in quantity 1 · ~\)0.20–0.40 each in packs of 10–20.

Search keywords: 3 pin screw terminal block 5.08mm, PCB screw terminal connector 3 way, KF128 3P 5.08mm

Where to buy:

Heat Shrink Tubing

Heat gun shrinking colored tubing over soldered strip leads

Colored heat shrink over the strip's soldered joints does two useful jobs at once. It strain-relieves the connection, which matters because WS2812B pads lift off the strip easily when a wire gets tugged. And it color-codes the three leads — red for 5V, black for ground, and a third color for data — so students wire the strip correctly without tracing each wire back to the pad.

This is optional in the sense that the kit works without it. In practice it is the difference between kits that survive a semester and kits that come back with a lifted pad.

Prep work: Slide the tubing over each wire before soldering, then shrink it afterward with a heat gun. Sliding it on after the joint is made is not possible, which is the mistake everyone makes exactly once. About 2 minutes per strip.

Cost: ~\(6–12 for an assorted multi-color, multi-diameter box · one box prepares a whole classroom's strips, so budget it per classroom (~\)10), not per student. A heat gun runs $15–25; the side of a soldering iron also works, but a hair dryer will not get hot enough.

Search keywords: heat shrink tubing assortment kit, colored heat shrink tubing 2mm 3mm, 3:1 adhesive lined heat shrink

Where to buy:

Acrylic Base

Photo pending — see the image brief.

A base turns a loose breadboard and a dangling strip into an object a student can carry home and put on a shelf. We mount the breadboard on a rectangle of 3mm clear acrylic using its adhesive backing, and run the LED strip along the front edge. Any rigid flat material works — plywood and foam board are both fine — but acrylic looks finished and lets the strip's light glow through the edge.

Prep work: Cut to roughly 4" × 8" and drill mounting holes if you are screwing the strip down rather than using its adhesive. Peel the protective film only at the very end, or it will collect fingerprints during assembly. About 10 minutes each, or considerably less with a laser cutter.

Cost: ~\(2–5 each cut to size in quantity 1 · cheapest by a wide margin as one large sheet cut down locally (~\)25–40 for 20), or free as offcuts from a maker space or sign shop, which are usually happy to hand over scrap.

Search keywords: 3mm clear acrylic sheet, plexiglass sheet cut to size, acrylic sheet 12x12 3mm

Where to buy:

Purchasing Strategy

Lead time is the real tradeoff. Direct-from-China listings on AliExpress and many eBay sellers run 40–70% cheaper than Amazon for the same commodity part, at 2–3 weeks of transit — sometimes 4–6 weeks around Lunar New Year, when Chinese factories and shipping largely stop for two weeks or more. Order a semester ahead and the savings are free; order the week before the unit starts and you pay the Amazon premium for the privilege. The Pico is the exception: Micro Center's $3.99 price beats every other channel, domestic or not.

Buy one, then buy twenty. Order a single unit from a seller, confirm it is the right part, then place the classroom order with that same seller. Listings for commodity parts vary in quality far more than the photos suggest, and this applies double to Pico clones and LED strips.

Order spares. Add 10–15% over the class count. Buttons get lost, strips get cut short, someone reverses power and ground. Spares are cheaper than a dead station in the middle of a lesson.

Watch the pack sizes. Most of the classroom savings comes from pack breakpoints — breadboards in tens, buttons in hundreds — not from negotiated discounts. Round the order up to the pack, not to the roster.

Check your district's purchasing rules first. Many districts cannot reimburse AliExpress or direct international orders and require a domestic vendor with a W-9. If that is your constraint, the Amazon column is your real price, and the per-student figure lands closer to $15 than $10 — worth knowing before you promise a number to an administrator.

Classroom Order Worksheet

Quantities for a class of 20, rounded up to realistic pack sizes and including spares.

Part Required? Qty per kit Qty to order for 20 Est. cost
Raspberry Pi Pico Required 1 20 $80
Solderless breadboard Required 1 20 (2 packs of 10) $30
WS2812B LED strip, 1m Required 1/2 11 meters (1 spare) $35
Momentary push button Required 2 100 (1 pack) $6
22-gauge solid-core wire Required ~5 wires 1 spool set $12
Micro USB data cable Required 1 20 (multi-packs) $30
Required subtotal $193
Three-screw terminal header Optional 1 20 (packs of 10) $8
Heat shrink tubing Optional ~3 pieces 1 assortment box $10
Acrylic base Optional 1 1 sheet, cut down $30
With optional parts $241

Per student: ~\(9.65 required · ~\)12.05 with the optional parts

Shared classroom tools

These are bought once and used for years, so they are deliberately kept out of the per-student figure — folding a $30 soldering iron into a $10 kit misrepresents what the kit actually costs to run in year two.

Tool Cost How many
Soldering iron $15–40 1 per 4–6 students
Solder $8–15 1 spool per classroom
Wire strippers $8–15 1 per pair of students
Flush cutters $5–10 1 per pair of students
Heat gun $15–25 1 per classroom
Multimeter $10–25 1–2 per classroom

Prepping 20 strips is a lot of soldering for one person. We run it as a soldering party with parent volunteers — it takes an evening and it is considerably more fun than doing it alone.