A ready-made wiring diagram for every circuit in the course — no need to lay these out in Fritzing yourself. Each one lists every real connection as a colour-coded wire, plus the parts and any gotchas worth knowing before you pick up a breadboard. All physical pin numbers refer to the standard 40-pin Raspberry Pi header.
How to read these
One colour code, used throughout: red = power (3.3V/5V/external PSU), black = ground, teal = a GPIO signal wire. Match it on the breadboard and every circuit is easy to sanity-check at a glance.
Every circuit below is a test circuit — exactly what to breadboard to prove one subsystem works, matching the corresponding week's workbook page. None of them assume the others are already wired, so they can be built and tested in isolation.
If you'd still like a Fritzing file for a circuit — for a nicer breadboard-photo export, say — the parts tables below have everything needed to lay one out (Adafruit's importable parts are at github.com/adafruit/Fritzing-Library), but it's entirely optional now that the diagrams exist here.
Week 2
LED & switch test circuit
The simplest possible proof that GPIO output and input both work, before anything more expensive is at risk.
Parts
Part
Search for in Fritzing
Qty
Breadboard (half-size is plenty)
"breadboard" (core parts bin)
1
LED, 5mm
"LED" (core parts bin)
1
Resistor
"resistor", set value to 220Ω
1
Momentary pushbutton
"pushbutton" (core parts bin) — stands in for the real contact switch
1
Connections
From
To
Wire
Pi pin 11 (GPIO17)
220Ω resistor, leg 1
teal
Resistor, leg 2
LED anode (long leg)
—
LED cathode (short leg)
Pi pin 9 (GND)
black
Pi pin 38 (GPIO20)
Pushbutton, leg 1
teal
Pushbutton, leg 2 (diagonal)
Pi pin 34 (GND)
black
Wiring tipNo physical pull-up resistor is needed — the Pi's internal pull-up is enabled in software (GPIO.PUD_UP). Don't add one in the schematic, or the wiring will look right but not match what the code expects.
Diagram
No physical pull-up resistor needed — the Pi's internal pull-up (GPIO.PUD_UP) does that job in software.
Week 5
Stepper motor & homing switch
The Motor HAT sits on top of the Pi's own header, so in breadboard view it's usually clearest to draw it as its own labelled block rather than trying to show all 40 pass-through pins.
Parts
Part
Search for in Fritzing
Qty
Adafruit Motor HAT
Adafruit Fritzing-Library, or draw as a labelled generic IC/board outline if not found
1
NEMA-17 stepper motor
"stepper motor" (core parts bin has a generic 4-wire stepper)
1
Limit/contact switch
"pushbutton" or "slide switch" as a stand-in
1
External power supply
"battery" or "power supply" (core parts bin), relabelled
1
Connections
From
To
Wire
Pi 40-pin header
Motor HAT header (stacked)
— (HAT sits directly on top)
Motor HAT, "M1" stepper port (4 pins)
Stepper motor, 4 coil wires
match coil pairs — see the motor's datasheet for which two wires form each coil
External PSU +/-
Motor HAT power terminal block
red / black
Pi pin 38 (GPIO20)
Limit switch, leg 1
teal
Limit switch, leg 2
Pi pin 34 (GND)
black
CarefulThe Pi's own 5V rail cannot supply a stepper motor — the external PSU is not optional. Never wire the motor's power straight to the Pi.
Diagram
The Motor HAT stacks on the Pi's 40-pin header (not shown as a separate wire) — the Pi's own 5V rail cannot power the motor, so the external PSU is not optional.
Week 7
AS7341 colour sensor & NeoPixel
Two independent circuits doing two different jobs: I2C for the colour sensor, which has its own onboard LED for illuminating the Skittle, and a single data line for the NeoPixel, which is purely a user-feedback indicator and plays no part in the sensor reading.
Parts
Part
Search for in Fritzing
Qty
Adafruit AS7341 breakout
Adafruit Fritzing-Library — confirmed present as Adafruit AS7341.fzpz
1
NeoPixel strip (user-feedback indicator only)
Adafruit Fritzing-Library has NeoPixel Jewel/strip parts; search "NeoPixel"
1
Connections
From
To
Wire
Pi pin 1 (3V3)
AS7341 VIN
red
Pi pin 9 (GND)
AS7341 GND
black
Pi pin 3 (GPIO2 / SDA)
AS7341 SDA
teal
Pi pin 5 (GPIO3 / SCL)
AS7341 SCL
teal
Pi pin 2 (5V)
NeoPixel 5V
red
Pi pin 6 (GND)
NeoPixel GND
black
Pi pin 32 (GPIO12)
NeoPixel DIN
teal
Wiring tipDraw the sensor and the NeoPixel as two clearly separate wire bundles even though they share the Pi's GND — the AS7341's own onboard LED handles illumination entirely on its own, and the NeoPixel exists purely to give the operator visual feedback, so keeping them visually separate here matches how the workbook explains it.
Diagram
Two independent circuits sharing only the Pi's ground — I2C for the sensor (whose own onboard LED handles illumination), a single data line for the NeoPixel feedback strip.
Week 9
Second stepper & sort switch
Identical pattern to Week 5, on the Motor HAT's second port and a different GPIO pin so both switches can be read independently.
Connections
From
To
Wire
Motor HAT, "M2" stepper port
Second stepper motor, 4 coil wires
—
Pi pin 12 (GPIO18)
Second limit switch, leg 1
teal
Second limit switch, leg 2
Pi pin 34 (GND) — or any other GND pin
black
Wiring tipIt's the same shape as Week 5 on purpose — only the Motor HAT port and the switch's GPIO pin (18 instead of 20) change.
Diagram
Same pattern as Week 5, on the HAT's second port and a different GPIO pin (18, not 20) so both switches read independently.
Week 11
TFT Bonnet, relocated via ribbon cable
Not a raw ST7789 breakout wired pin-by-pin — the Adafruit 1.3″ TFT Bonnet (product 4506) has a fixed pinout built into the board. The only wiring decision here is how to get its 40 pins from the Pi's header to wherever the bonnet is physically mounted.
Adafruit Fritzing-Library — search "TFT Bonnet"; if absent, use a generic labelled HAT outline
1
40-pin GPIO stacking header (passes every pin through)
"GPIO stacking header" / "40-pin header"
1
40-pin GPIO ribbon cable
"40-pin ribbon cable" / "GPIO ribbon"
1
Connections
Every one of these is fixed by the bonnet itself — nothing here is a wiring choice, it's what the board does the moment the ribbon cable is connected.
From
To
Wire
Pi 40-pin header
Stacking header (passes all 40 pins through)
red
Stacking header
Motor HAT — unchanged from Weeks 5/9
red
Stacking header
40-pin ribbon cable → TFT Bonnet
red
Bonnet pin 19 (GPIO10 / MOSI)
bonnet SPI MOSI
teal
Bonnet pin 23 (GPIO11 / SCLK)
bonnet SPI SCLK
teal
Bonnet pin 24 (GPIO8 / CE0)
bonnet SPI CS
teal
Bonnet pin 22 (GPIO25)
bonnet D/C
teal
Bonnet pin 37 (GPIO26)
bonnet backlight
teal
Bonnet pins 11, 13, 15, 16 (GPIO17/27/22/23)
joystick, 4 directions
teal
Bonnet pin 7 (GPIO4)
joystick click
teal
Bonnet pins 29 & 31 (GPIO5 / GPIO6)
front buttons A & B
teal
Unlike a raw breakout, there's no separate RST pin to wire — the bonnet doesn't expose one.
Diagram
The bonnet's pinout is fixed by the board itself, not a choice — every one of these connections happens automatically the moment the ribbon cable is plugged in. The stacking header is what lets the Motor HAT and the bonnet share the same 40 pins at once.