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SeedBox hardware bill of materials

Welcome to the gear dump. This is the parts bin manifest for anyone who wants to spin up a physical SeedBox instead of just vibing with the native build. Read it like a tour guide and a shopping list rolled into one: grab the essentials, flag the optional bling, and learn why each piece exists so you can sub in alternatives without frying the groove. Once parts land, flip to the wiring gallery for routing photos and the calibration guide before you ever power the stack.

Core brain stack (must-haves)

Item Suggested part numbers & sources Why it matters Notes
Teensy 4.0 microcontroller PJRC DEV-15583; SparkFun, Adafruit resellers Runs the audio engine at silly-fast speeds with floating-point DSP. Order at least one spare if you plan to field-debug.
PJRC Audio Shield (Rev D or later, SGTL5000) PJRC DEV-16829 Breaks out I²S, codec, and headphone amp so we can hear anything. Works on Teensy 4.x with minor solder jumpers pre-made.
0.1" stacking headers for Teensy + audio shield 14-pin & 24-pin stackable header kits Physically mates the Teensy and audio shield without mangling test access. Go for tall stackers if you plan to wire extra boards underneath.
SparkFun Qwiic OLED 1.3" 128×64 (I²C, SH1107) LCD-17153 Debug + UI status display with enough pixels for verbose seed gossip. Qwiic connector + castellated pads, 3.3 V only, on-board pull-ups already present.
Rotary encoders with integrated push buttons (x2) PEC11R, Bourns, or Alps clones Primary human input for parameter twiddling. Choose detent style you enjoy; 24 PPR feels right.
Momentary push buttons (x2) Panel-mount SPST normally-open Transport control / macros. Grab low-profile caps if you’re building a handheld case.
10 kΩ resistors (through-hole or SMD, x4) E12 series kit Pull-ups for buttons and encoders. Metal film is fine; 1/8 W or 1/4 W.
Hook-up wire (26–28 AWG, solid) Wire kit or ribbon cable Routes signals from Teensy to panel controls. Solid wire makes breadboarding easier; switch to stranded for flex joints.
USB-C to micro-B cable Any data-capable cable Powers and programs the Teensy. Keep a short, shielded cable for reduced noise.

Signal hygiene & audio path helpers

Item Suggested part numbers & sources Why it matters Notes
4.7 kΩ resistors (x2) For I²C pull-ups Stabilizes the OLED bus when multiple peripherals hang out. Skip them when the SparkFun Qwiic OLED is alone on the bus—the breakout already has them.
100 nF ceramic capacitors (assorted) Bypass kit Decouple encoder and button lines against switch bounce noise. Solder between signal and ground right at the panel.
Stereo 3.5 mm TRS jack PJ-320D, Switchcraft 35RAPC2AV Audio output to headphones/mixer. Mount close to the audio shield to avoid hum loops.
Panel-mount USB extension (optional) USB micro-B panel adapter Keeps the main USB port accessible in an enclosure. Ensure it supports data, not just charging.

MIDI & sync accessories

Item Suggested part numbers & sources Why it matters Notes
3.5 mm TRS jacks (Type-A, x2) PJRC T35-TRS, Adafruit 4399, DIYCables panel jacks Modern MIDI I/O without adapters. Follow the Type-A pinout: tip = MIDI+, ring = MIDI−, sleeve = ground. Route the IN jack to Serial7 RX (pin 28) and the OUT jack to Serial7 TX (pin 29) through the proper resistors.
6N138 or PC900 opto-isolator MIDI IN isolation Complies with the MIDI electrical spec so your rig survives bad cables. Remember the 220 Ω + 1 N4148 LED protection network.
220 Ω resistors (x2) MIDI input current limiting Works with the opto-isolator LED. 1/4 W carbon film is fine.
33 Ω resistors (x2) MIDI Type-A output impedance Protects the Teensy pins and meets the spec when driving TRS. Mount them inline on the TX leg before the jack.
1 N4148 diodes (x2) MIDI input protection Shields the opto LED from reverse voltage. Any fast small-signal diode works.
MIDI breakout PCB or perfboard DIY layout platform Keeps the opto, resistors, and jack tidy. Perfboard is fine for prototypes.

Power management odds and ends

Item Suggested part numbers & sources Why it matters Notes
Breadboard-friendly DC barrel jack (optional) 2.1 mm center-positive Lets you inject external 9–12 V if you ditch USB power. If you power externally, cut the Teensy VUSB/VIN trace and add a regulator.
5 V to 3.3 V regulator (optional) Pololu S7V8F3 or LD1117-3.3 linear reg Powers peripherals when USB cannot. Only needed for standalone rigs with beefy peripherals.
Power switch (latching) Panel toggle or slide Gives you a true off switch when running from external power. Place on the high side before regulators.

Fasteners, mechanical bits, and creature comforts

Item Suggested part numbers & sources Why it matters Notes
M2.5 or M3 standoffs (nylon or metal) 10 mm + 12 mm lengths Secures Teensy + audio shield sandwich to your panel or baseplate. Mix nylon + metal to avoid accidental shorts.
Laser-cut or 3D-printed enclosure panels DIY Keeps fingers off the high-speed digital pins. Share your CAD files in /docs/ when you iterate.
Knobs for encoders (x2) Rogan soft-touch, Davies 1900H Makes the interface feel like an instrument. 6 mm D-shaft for most encoders.
Rubber feet or adhesive bumpers Hardware store Stops the box from skating off the table during live tweaks. Cheap insurance.
Label tape / paint pen Sharpie, Brother Mark I/O and debug headers for future-you. Hand-written labels > no labels.

Tools you actually need on the bench

Tool Why Notes
Temperature-controlled soldering iron + fine tip Clean joints on Teensy headers and panel wiring. Hakko FX-888D class or better keeps frustration low.
Leaded solder (0.5–0.7 mm) Easier to work with than lead-free for prototypes. Ventilate the room, please.
Flush cutters & needle-nose pliers Trim leads, bend wires, tame headers. The $10 Amazon kit is fine, upgrade as they dull.
Multimeter Sanity-check power rails and continuity. Autoranging handheld units are plenty accurate here.
Logic analyzer or USB oscilloscope (optional) Debug MIDI/clock edges, verify I²S lines. Saleae clones work in a pinch; document captures in /docs/.
Helping hands or PCB vise Hold the stack-up while you solder. Your wrists will thank you.
Breadboard or perfboard Prototype input circuits before committing. Keep one dedicated to MIDI testing.

Shopping notes & sourcing hacks

  • Buy extras of cheap passives and encoders. Hardware gremlins love to eat the last resistor at 1 a.m.
  • Group orders with friends to dodge shipping gouges on PJRC parts. Teensy boards ship fast from the mothership, but mixing in Digikey/Mouser orders keeps everything on one invoice.
  • Remember the Qwiic pigtails. The SparkFun OLED speaks JST-SH and 3.3 V only; if you're not chaining other Qwiic widgets, a short cable or hand-soldered ribbon straight to SDA/SCL keeps the wiring tight and quiet.
  • Document substitutions. If you drop in a different OLED module or encode a bespoke panel PCB, leave a note (and ideally a photo) in this doc so the next builder inherits the lore.
  • Track firmware expectations: whenever the pinout changes, update docs/builder_bootstrap.md so the wiring map matches the real world.

Open invites for contributors

This manifest is intentionally scrappy. When you validate a new encoder family, find a boutique knob that sparks joy, or design a case that survives gig backpacks, add it here with prices, photos, and caveats. The more we annotate why a part made the list, the easier it is for students and collaborators to mod the rig without fear.