led-bar
The example of the handbook: a Raspberry Pi Pico 2 drives eight LEDs through a TLC5916 constant-current sink, 5 V through a JST PH connector and a reverse diode, one button. Every reference circuit adds its domain's circuit to it.
Reference circuits
edakit's own circuits, one per domain, each added to the example and drawn by edakit schematic draw. Each passes edakit check and edakit sim clean under its domains; each seeded fault raises exactly its codes (tests/test_reference.py). The values are chosen for the test, not taken from datasheets.
motors
M1 (33 Ω winding) from +5V to the collector of an S8050 Q20, 1 kΩ from GP8 to the base, 10 kΩ base to emitter; an SS14 across the winding.
audio
U20, a class-D amplifier on +5V with 100 nF, its bridge-tied outputs to the speaker LS20; its input from GP8 through the PWM DAC's low-pass R20 1 kΩ / C21 10 nF (C0G) – an AC run expects its corner at 15.9 kHz: flat at 1 kHz, the upper −3 dB corner between 10 and 25 kHz.
guitar
An instrument buffer: the jack J20's tip on GTR_IN (a pickup that wants at least 1 MΩ), 2.2 MΩ to the reference VREF (10 kΩ / 10 kΩ from +5V, 22 µF), U20 an op-amp follower on +5V with 100 nF; its output coupled through C22 1 µF (film) onto BUF_OUT with R24 100 kΩ to ground – an AC run expects the follower flat at 1 kHz and the coupling's corner, 1.6 Hz, below 10 Hz.
power
Three AA cells in BT20 next to USB: through an SS14 D20 onto VIN behind J1, so that neither feeds the other.
cables
A button SW20 on a hand-wired remote board, wired by cable W20 (1 m of AWG 26) from J21 to J20 on main; on main the line reaches GP8 through 1 kΩ, with 10 kΩ to 3V3.
usb
J20, a USB-C receptacle for data: 5.1 kΩ from each CC pin to GND, D+ and D− of both rows joined to GP8 and GP9 through 27 Ω.
keyboard
A 2 × 2 key matrix: SW20–SW23 from the rows (GP8, GP9) to an SS14 each, cathodes to the rows, anodes … the columns (GP10, GP11).
