Electronics Hardware Quick Reference

1. How to use this document

You will not read this end-to-end. Use it like a dictionary with a learning path on top.

Day 1 of your co-op: skim sections 2–4 (Prerequisites, Suggested Path, the Practical 20 list at the end of section 5). That alone puts you ahead of most interns.
When you hit an unfamiliar term in code or a meeting: Cmd-F the term in section 5. Each entry is self-contained.
When you want depth on a topic: follow the 📚 links at the bottom of the section. Those are the canonical, freely available resources — not random blog posts.
When you're about to wire a part on your bench: jump to the sister Hardware Quick Reference (link in the navbar) and look up the exact part — it cross-links back to the concepts here.

2. Prerequisites

You don't need an EE degree, but the following mental model is assumed throughout this document. If you don't have it, the Practical 20 in section 4 will catch you up over a week.

Math (intuition, not proofs):

Algebra: solve for an unknown. Why: every circuit calculation is solving V = IR for one of the three.
Trig: sine, cosine, frequency, phase. Why: AC analysis, audio, filters, control loops.
Logarithms. Why: decibels, RC time constants, RC filter cutoff math.

Programming (one of these is enough):

Python — the default for MicroPython on the Pico and ESP32-S3. You should be comfortable with classes, decorators, async, and type hints.
C / C++ — for ESP-IDF, Arduino, or any low-level work. Pointers, structs, volatile, static, bit manipulation.
Shell — cd, ls, grep, |, >, python -m venv, esptool.py.

Tools to install (do this on day 1):

# Thonny (the friendliest MicroPython IDE — recommended for first month)
sudo apt install thonny   # or download from thonny.org

# mpremote — the official MicroPython command-line tool
pip install mpremote

# esptool — for flashing ESP32 / ESP32-S3 boards over USB
pip install esptool

# Arduino IDE 2.x — for Arduino C/C++ projects
# Download from arduino.cc

3. Suggested build order (5 steps)

Do these in order. Each step is one bench session. By step 5 you will have used every part family in your inventory at least once.

Step 1 — Get the basics wired and verified

Set up your Raspberry Pi Pico W or ESP32-S3-DevKitC-1 on a breadboard, power it over USB, and blink the on-board LED using jumper wires. Add a current-limiting resistor and an external LED. Verify your USB cable is data (not charge-only) by opening the serial monitor. Goal: prove the “edit → flash → see result” loop works for you.

Step 2 — Add sensors (input)

Wire the KY-018 LDR and KY-013 thermistor to an ADC pin via a voltage divider. Then the MPU-6050 IMU over I²C. Then the INMP441 microphone over I²S. Print all the values to the serial console. Goal: every input you own produces a number on the screen.

Step 3 — Add outputs (the SSD1306 OLED is your friend)

Connect the SSD1306 OLED over I²C and display your sensor values. Add the TB6612FNG + N20 gearmotor stack with the 12 V supply for motion. If you have an SG90 servo, drive it from a separate 5 V rail. Goal: input → display → motion, all in one project.

Step 4 — Add communication and audio

Add the DFPlayer Mini for sound (start with the speaker and a pre-made MP3 file). Add the MAX98357A + mini speaker for I²S audio from the MCU. Add the HC-SR04 ultrasonic distance sensor. Add the WS2812B strip with the 74HCT125 level shifter. Goal: every output family in your inventory has been used at least once.

Step 5 — Power and the real-world bits

Switch from USB to a 18650 + MT3608 boost (or a Mini360 buck from a 12 V supply) and verify your project still boots and the rails are correct under load. Add a tactile button + slide switch for user input. Add a status LED with a resistor on every power rail so you can see brownouts visually. Goal: the project survives being unplugged, moved, and plugged back in.

Optional but recommended: the A4988 / TMC2209 stepper driver + NEMA 11 stepper for precise motion; the HX711 load cell for force feedback; the ST7789 TFT for a full-color display. All listed in section 7.

4. The Practical 20 — read these first

If you only read 20 entries in this glossary, read these. They cover ~90% of what you'll see in your first month on a microcontroller project.

Each entry: a one-line definition, then a practical note in italics that says what it means on the bench. Entries marked 🔥 are the practical-20.

Letter

A

3 terms

A3144 Hall-Effect Sensor

A TO-92 omnipolar Hall switch. Outputs LOW when a magnetic field is present (regardless of polarity). Open-drain output, needs a pull-up to 3.3 V or 5 V. Practical: 2.5–24 V supply, 25 mA sink current, very fast (can switch at kHz rates). Use for: row counters (mount a magnet on the moving carriage; the A3144 sits on the frame), rotation counting on a motor shaft, door sensors. Wiring: pin 1 = VCC, pin 2 = GND, pin 3 = OUT (open-drain). Add a 10 kΩ pull-up from OUT to VCC. See also: Hall Sensor, Open-Drain / Open-Collector, Pull-up / Pull-down Resistor.

A4988 Stepper Driver

A bipolar stepper motor driver IC on a carrier PCB. Logic-voltage STEP and DIR inputs; 8–35 V motor supply; 1 A continuous per phase, 2 A peak; microstepping up to 1/16. Practical: The de-facto stepper driver for an ESP32-driven project. Three wiring groups: (1) logic — STEP, DIR, EN̅, GND to MCU; (2) motor — 1A, 1B, 2A, 2B to the stepper coil pairs; (3) power — VMOT (8–35 V) and GND, with a 100 µF bulk cap right at the board. Watch for: the A4988 has a loud chopper — use TMC2209 for silent motion. See also: Stepper Motor (NEMA 11 / NEMA 17), TMC2209 v1.3 Silent Stepper Driver, PWM (Pulse-Width Modulation).

AHT20 + BMP280 Combo Module (T / RH / Pressure)

A 2-sensor I²C breakout with the AHT20 (temperature + humidity, ±0.3 °C / ±2 % RH) and the BMP280 (temperature + barometric pressure, ±1 hPa). Practical: The default weather-station sensor pair. Addresses: AHT20 = 0x38, BMP280 = 0x76 (or 0x77 if SDO is tied high). Watch for: the BMP280 can be in 'sleep' mode at power-up; send a 'set mode to normal' command (0xF4 = 0x57) before reading. The two sensors are close together on the board — the BMP280's self-heating will skew the AHT20 by ~1 °C; read the AHT20 first then average. See also: I²C (Inter-Integrated Circuit), Address (I²C / SPI).

Letter

B

2 terms

Breadboard 830 Tie-Point

A solderless prototyping board: 2 power rails × 50 columns + 63 × 2 terminal strips × 30 rows, total 830 tie points. Your kit has 2 of these. Practical: The 30 rows of 5 holes each are connected internally — a component's two leads go in the same row to be connected. Power rails are vertical (top red, bottom blue typically) and run the full length. Watch for: (1) the power rails are usually broken in the middle on full-size boards — bridge with a jumper if you need full-length power; (2) high-current loads (> 1 A) have poor contact — solder instead. See also: Jumper Wire, Capacitor (Decoupling / Bypass).

Brother KR830 Standard-Gauge Latch Needle

A 100-pack of Brother KH-830/KH-840/KH-930 standard-gauge 4.5 mm latch needles. Each needle is a 4-piece assembly (latch, tongue, body, cap) with a hook on the end. Practical: The single longest-lead item in your inventory (Etsy / eBay / AliExpress, weeks to months). Order FIRST even if you delay the rest of the weaver BOM. Watch for: these are the only moving part on a knitting machine — any burr or bend means a missed stitch. Handle by the body, never the latch. See also: Solenoid, Servo Motor (SG90 / Standard).

Letter

C

1 term

Capacitor Assortment (Aluminum Electrolytic)

A mixed set of aluminum electrolytic capacitors, 10 V to 450 V working voltages, assorted µF values. Practical: These are polarized (stripe = negative, longer lead = positive). Use for bulk energy storage on power rails, audio coupling (large µF values), and timer circuits. Match the voltage rating with margin: a 10 V cap on a 5 V rail is fine; a 10 V cap on a 12 V rail will fail within months. Watch for: the 400 V and 450 V parts are huge (the size of a D-battery) — keep them on the shelf for tube-amp or CRT projects. For decoupling on MCUs, use ceramic (smaller, faster). See also: Capacitor (Electrolytic), Capacitor (Ceramic), Capacitor (Decoupling / Bypass).

Letter

D

1 term

DFPlayer Mini MP3 Module

A small MP3 playback board that reads from a microSD card or USB flash drive and outputs audio to a speaker. UART-controlled (9600 baud default). Practical: The easiest way to add sound to an MCU project — no codec, no file system code, no audio library. Wire: VCC (3.3–5 V), GND, TX → MCU RX, RX ← MCU TX (use a 1 kΩ series resistor on the DFPlayer's TX since some clones output 5 V). Put .mp3 files named 0001.mp3, 0002.mp3 on a FAT32 microSD. Send 0x7E 0x03 0x00 0x01 0xEF to play track 1. Watch for: it can't drive a speaker directly at much volume — pair with a PAM8403 or MAX98357A amp for louder output. See also: UART (Universal Asynchronous Receiver/Transmitter), Amplifier (Op-Amp / Class-D), Baud Rate.

Letter

E

4 terms

ESP32-CAM (OV2640 / CH340 carrier)

A small board with an ESP32-S, an OV2640 2 MP camera (or the OV3660 3 MP variant you own), a CH340 USB-serial bridge, and a microSD slot on the bottom. Wi-Fi + BT, dedicated camera DVP interface, 4 MB flash. Practical: The cheapest way to get a camera on Wi-Fi. Two gotchas: (1) it has no USB-serial on the module itself — the carrier adds the CH340, but the GPIO0 (flash) button and the 5 V input are not on a standard pin header. (2) the on-board antenna is poor — for any range, swap to a U.FL variant or add a pigtail. The board runs the standard ESP-IDF camera example; for AI work, pipe the JPEG stream to a small VLM on a more capable host. See also: ESP32 / ESP32-S3 / ESP32-C3, ESP32-CAM (OV2640 / CH340 carrier), Wi-Fi (802.11).

ESP32-S3-DevKitC-1 (N16R8)

The primary dev board for your projects. ESP32-S3 dual-core LX7 @ 240 MHz, 16 MB flash, 8 MB PSRAM, Wi-Fi 4 + BLE 5, USB-C with built-in USB-JTAG/serial, 38-pin breakout with 40+ GPIO. Practical: The 'N16R8' suffix: N16 = 16 MB flash, R8 = 8 MB PSRAM. The PSRAM is what lets you use the camera at > XGA resolution or hold large audio buffers. Three things to set in every project: (1) the USB CDC is on GPIO19/20 by default — don't wire those to sensors; (2) the on-board RGB LED is on GPIO48 (some clones use GPIO38); (3) GPIO0, GPIO3, GPIO45, GPIO46 are boot-strap pins. See also: ESP32 / ESP32-S3 / ESP32-C3, Boot Mode / Boot Button, ESP32-S3-DevKitC-1 (N16R8).

ESP32-S3 WROOM-1 (raw module)

A bare ESP32-S3 module (the chip + crystal + antenna + flash/PSRAM, 44-pin castellated edge). 16 MB flash, 8 MB PSRAM. Practical: Used when you're building a custom PCB and don't need a dev board. The 44 castellated pads are 0.1″ pitch, half-vias — you solder them to your PCB pads directly or use a carrier board. Note: the AliExpress listing you bought from shows a suspiciously low price (C$0.45) — verify on receipt that you actually got a module and not a header-pin bundle. See also: ESP32 / ESP32-S3 / ESP32-C3, PCB (Printed Circuit Board).

ESP32-S3 38-pin Expansion Bottom Board

A passive carrier that breaks out the 38-pin DevKitC-1 footprint to labeled 0.1″ headers, often with both Micro USB and Type-C connectors, plus 3.3 V / 5 V power pins. Practical: A 'bench-friendly' alternative to the official dev board — same pinout, more accessible labels, often cheaper. No MCU is on the board; you snap the DevKitC-1 module into the matching header. See also: Shield / Carrier / Breakout.

Letter

G

1 term

GA12-N20 Micro Metal Gear Motor

A 12 mm × 12 mm brushed DC gearmotor with metal gears. Your batch is 300 RPM @ 6 V, single shaft, 2-wire. The 'N20' is the form factor; speed is specified per part. Practical: The workhorse small DC motor for robotics. Stall current ~200 mA, no-load current ~50 mA. Pair with the TB6612FNG driver and a 6 V supply. Watch for: (1) N20 motors have integrated gearboxes — do not oil the gear, it doesn't need it; (2) the shaft is 3 mm diameter with a D-flat — press-fit wheels or couplings work; (3) for encoder feedback, buy the 'with encoder' variant (different PCB at the back). See also: TB6612FNG Dual Motor Driver (1 A), GA12-N20 Micro Metal Gear Motor, PWM (Pulse-Width Modulation).

Letter

H

4 terms

74HCT125 (Quad Buffer / Level Shifter)

A 14-DIP or SOIC-14 IC with 4 non-inverting 3-state buffers. Used in your planned BOM as a 3.3 V → 5 V level shifter for the WS2812B DIN line. Practical: The HCT family is the magic — its inputs are TTL-compatible (3.3 V CMOS drives them as a clean HIGH), and its outputs are 5 V CMOS. Pinout: 1A → 1Y, 2A → 2Y, etc., with 1OE̅, 2OE̅ active-low enable per buffer. Tie OE̅ to GND to enable; tie to 5 V to tri-state. Watch for: this only goes 3.3 V → 5 V (one direction). For bidirectional, use a TXS0108E or a discrete MOSFET shifter. See also: CMOS vs TTL Logic Levels, Level Shifter, WS2812B Addressable RGB LED Strip.

HC-SR04 Ultrasonic Distance Sensor

A 4-pin ultrasonic ranging module: 5 V supply, Trig input, Echo output, GND. Range 2 cm – 400 cm, accuracy ~3 mm. Practical: The classic beginner distance sensor. Send a 10 µs pulse to Trig, measure the pulse width on Echo (in microseconds), divide by 58 to get cm. Watch for: the Echo pin is 5 V logic — the ESP32 and Pico are NOT 5 V tolerant on GPIO. Use a voltage divider on Echo: 1 kΩ in series + 2 kΩ to GND, tap the middle for the MCU. Or use the HC-SR04+ (3.3 V compatible). See also: Level Shifter, Voltage Divider, PWM (Pulse-Width Modulation).

Hex Nuts & Bolts Set (M2 / M2.5 / M3 / M4 / M5)

A 640-piece metric fastener kit covering M2, M2.5, M3, M4, M5 in both socket-head cap screws and matching hex nuts. Practical: The single most useful kit on your bench. Default sizes: M2 for PCBs and small sensors, M2.5 for 3D-printed brackets (matches the standard heat-set insert), M3 for N20 motor mounts and most 3D-printer accessory screws, M4 for structural, M5 for legs and feet. Buy more of the sizes you use (M3 is always the first to run out). Watch for: metric and SAE (imperial) do not mix — a 4-40 is not the same as M2.5, but it's close enough to be a footgun.

HX711 + 1 kg Load Cell

A 24-bit ADC breakout (HX711) paired with a 1 kg half-bridge load cell. 10 Hz or 80 Hz sample rate, 5 V supply, 128× or 64× gain. Practical: The standard way to measure force, weight, or tension with an MCU. The HX711 connects via two GPIO (DOUT, SCK) — no I²C address. Wiring colors (most common): red = E+, black = E−, white = A+, green = A−. Calibration: read 100 samples with nothing on the cell (tare), then with a known weight (e.g. 100 g) to find the scale factor. Watch for: the load cell is sensitive to off-axis load and bending — mount it on a fixture that only applies the intended force. See also: Load Cell / Strain Gauge, Wheatstone Bridge, Amplifier (Op-Amp / Class-D).

Letter

I

2 terms

37-in-1 Sensor Kit (KY-001 to KY-040)

A bundle of 37 small sensor and actuator modules on standardized PCBs. The kit in your inventory includes 1× each of: DS18B20 temp (KY-001), vibration (KY-002), button (KY-004), IR emitter (KY-005), passive buzzer (KY-006), laser (KY-008), RGB LED (KY-009), photogate (KY-010), bi-color LED (KY-011), active buzzer (KY-012), thermistor (KY-013), DHT11 T/RH (KY-015), RGB LED SMD (KY-016), tilt (KY-017), LDR (KY-018), relay (KY-019), tilt (KY-020), reed (KY-021), IR receiver (KY-022), joystick (KY-023), Hall (KY-024), reed (KY-025), flame (KY-026), cup (KY-027), thermistor (KY-028), bi-color LED (KY-029), knock (KY-031), IR obstacle (KY-032), line tracker (KY-033), 7-color flash (KY-034), bi-color LED (KY-035), touch (KY-036), reed (KY-037), mic (KY-038), pulse (KY-039), rotary encoder (KY-040). Practical: 3-pin modules share a standard pinout: S/VCC, G/GND, OUT/IN on the 3-pin header — the same JST-PH cable works for all of them. 4-pin modules add a second signal line (analog + digital on the same module). Start with the LDR (KY-018), button (KY-004), and IR obstacle (KY-032) — three sensors, three interfaces (ADC, digital, digital), one afternoon of learning. See also: I²C (Inter-Integrated Circuit), I²S (Inter-IC Sound), PWM (Pulse-Width Modulation), SPI (Serial Peripheral Interface).

INMP441 Omnidirectional MEMS Microphone (I²S)

A high-performance bottom-port MEMS microphone with an I²S digital output. 24-bit PCM, 44.1 kHz or 48 kHz sample rate, ±3 dB tolerance, ~50 dB SNR. Practical: The I²S output is the key — it skips the analog noise of an analog mic + ADC. You can chain multiple INMP441s on one I²S bus by tying SCK + WS in parallel and using a different SD GPIO for each (or use the WS line as 'left vs right' channel select for two mics). Watch for: the breakout board is 3.3 V only — do not power from 5 V. The MCLK pin is left unconnected; the I²S peripheral generates BCLK internally. See also: I²S (Inter-IC Sound), DMA (Direct Memory Access), Decibel (dB).

Letter

J

2 terms

Jumper Wire Kit (M-M / M-F / F-F)

A 65-piece mixed set of 20 cm pre-crimped Dupont jumper wires, color-coded. Your kit covers male-male, male-female, and female-female in the standard rainbow set. Practical: The 'glue' of breadboarding. Color discipline: red = power, black = ground, one color per signal. Don't use 30 cm wires on a breadboard — the extra length picks up noise, and the bundle is a mess. Watch for: Dupont connectors are rated for ~2 A and have ~0.1 Ω contact resistance — they're fine for signals and small power, bad for motors or LEDs at full current. For production, crimp real JST-PH or JST-XH connectors. See also: Jumper Wire, BNC / SMA / USB-C / Barrel Jack.

JST-PH 2.0 mm Connector Kit

A 230-piece assortment of 2.0 mm-pitch JST-PH housings (2/3/4/5-pin) and crimp female pin headers. The standard for LiPo battery leads and small sensor cables. Practical: The 2.0 mm pitch is half of 0.1″ (2.54 mm) — do not confuse with 2.54 mm Dupont on a breadboard. Crimping: use a proper SN-28B or Engineer PA-09 crimper ($25). The contact has a tiny tang that locks into the housing — you can crimp with pliers in a pinch, but it will fail in 6 months. Watch for: the listing photo often shows 2.54 mm housings even when the title says 2.0 mm — verify on receipt. See also: BNC / SMA / USB-C / Barrel Jack, Jumper Wire.

Letter

K

1 term

KY-018 LDR (Photoresistor)

A light-dependent resistor in the standard 3-pin KY- module format. Resistance drops from ~1 MΩ (dark) to ~1 kΩ (bright light). Practical: Read with a voltage divider: 10 kΩ fixed resistor + LDR in series, ADC on the middle. Use for: ambient light sensing, line-following robots, sunrise/sunset detection. Watch for: the response is non-linear and slow (~50 ms time constant) — fine for ambient light, useless for flicker or fast pulses. For a faster photodiode, use a BPW34 with a transimpedance amp. See also: ADC (Analog-to-Digital Converter), Voltage Divider, Thermistor (NTC / 10 kΩ).

Letter

M

6 terms

MAX98357A I²S Class-D Amplifier (3 W)

A 3 W mono Class-D amplifier that takes an I²S digital audio input and drives a 4–8 Ω speaker. 3.3 V or 5 V supply, no I²C configuration needed. Practical: The right way to add audio output to an ESP32-S3 or Pico W. Wiring: BCLK, LRCLK, DIN from the MCU's I²S peripheral, SD (shutdown/select) tied HIGH to enable, GAIN to GND for 12 dB gain (or HIGH for 15 dB). Watch for: the MAX98357A outputs a PWM-like switching waveform — add a 10 µH inductor + 1 µF cap LC filter on the output for cleaner audio if the speaker wire is long. See also: I²S (Inter-IC Sound), Amplifier (Op-Amp / Class-D), Amplifier (Op-Amp / Class-D).

Mini360 DC-DC Buck Module (MP2307)

A 10-pack of tiny buck converters based on the MP2307 chip. 4.75–23 V input, 1–17 V output, 1.8 A continuous. 17 mm × 11 mm board, 340 kHz switching. Practical: The workhorse small buck for stepping down a battery or wall-wart to a logic rail. Set the output with the multi-turn pot before connecting your load (measure with a multimeter). Watch for: the MP2307 is a 340 kHz buck — its input ripple is audible on AM radio and can confuse ADCs if the input cap is undersized. Add a 100 µF electrolytic on the input if the supply is a wall-wart or a long wire. See also: Buck Converter, LDO (Low-Dropout Regulator).

MPU-6050 (GY-521) IMU

A 6-axis Inertial Measurement Unit: 3-axis gyroscope + 3-axis accelerometer, I²C interface (address 0x68 default, 0x69 if AD0 is high). The GY-521 is the standard breakout. Practical: The most-used IMU in hobby robotics. Two gotchas: (1) the sensor supports both 3.3 V and 5 V supply, but the I²C lines are 3.3 V logic — fine for any modern MCU, marginal for a 5 V Arduino on a long wire; (2) the sensor has a 32.768 kHz crystal (or no crystal, depending on variant) — for high-accuracy timing, use the DMP (Digital Motion Processor) firmware on the chip, not your MCU. Watch for: it does NOT have a magnetometer — for full 9-DoF (with heading), add an HMC5883L or use the MPU-9250. See also: I²C (Inter-Integrated Circuit), Address (I²C / SPI).

MT3608 Step-Up Boost Module

A 2–24 V → up to 28 V boost converter based on the MT3608 chip, 2 A peak, 1.2 MHz switching. Your kit has 7 total (2 from Creative DDN, 5 from EXinko). Practical: The default boost for a 3.7 V LiPo → 5 V or 12 V project. Set the output voltage with the multi-turn pot before connecting the load — the pot is fragile and the default is rarely what you want. Watch for: the MT3608 needs a real input cap (≥ 22 µF) or it will oscillate; the 1.2 MHz switching means add a ferrite bead on the input if the source is a battery. See also: Boost Converter, Bleed Resistor, MT3608 Step-Up Boost Module.

microSD Card SPI Breakout (3.3 V)

A generic microSD card adapter with a 3.3 V LDO and a 74LVC125A level shifter on-board. 6-pin: VCC, GND, MOSI, MISO, SCK, CS. Practical: For any project that needs gigabytes of storage (data logging, audio recording, image capture). Watch for: the breakout is 3.3 V only — for a 5 V MCU, use a 5 V-tolerant variant or add a level shifter. Format the card as FAT32 (not exFAT — many MCU libraries don't support it). For reliable operation, allocate the full 512-byte sector buffer in PSRAM and use DMA. See also: SPI (Serial Peripheral Interface), EEPROM, Level Shifter.

Mini Speaker (4 Ω, 3 W)

A small 1.25 mm terminal speaker, 4 Ω impedance, 3 W power rating, 3525 form factor (35 × 25 mm). Practical: The default speaker for an MCU audio project. Watch for: (1) 3 W is the max — drive it with the MAX98357A at 50% volume or less for long life; (2) the 1.25 mm terminals are tiny — crimp or solder directly, don't try to use a JST connector; (3) the speaker has no enclosure, so the bass response is poor — for music, put it in a small sealed box (~100 cm³). See also: Impedance, MAX98357A I²S Class-D Amplifier (3 W).

Letter

N

1 term

NEMA 11 Stepper Motor (28 mm, 0.6 A)

A small bipolar stepper, 1.8° step angle (200 steps/rev), 4-wire, 0.6 A per phase, 28 mm body length. The NEMA 11 is the 'small but real' stepper — 5× the torque of a 28 BYJ, with proper closed-loop potential. Practical: Wire pairs: A+/A− and B+/B−. With the A4988 driver, the default microstepping is 1/16, so 3200 microsteps per revolution — enough resolution for a knitting-machine carriage. Watch for: steppers draw full current even when holding position — size the supply (12 V × 2 A in your planned BOM is correct for 2 of these). Use TMC2209 for silent operation. See also: Stepper Motor (NEMA 11 / NEMA 17), A4988 Stepper Driver, TMC2209 v1.3 Silent Stepper Driver.

Letter

O

1 term

Omron-Style Micro Limit Switch

A sub-miniature SPDT switch with a hinged lever arm, rated 5 A @ 250 V AC. The 'Omron-style' on AliExpress is the SS5GL13 clone — pin-compatible with the Omron SS-5GL. Practical: The standard homing / endstop switch on a Cartesian robot, 3D printer, or spool knitter. Wire the COM and NO (normally-open) contacts to the GPIO and GND; enable the internal pull-up in software. Watch for: the lever arm has a small roller at the tip — position the switch so the cam or carriage hits the roller, not the lever body (which would bend). See also: Switch (SPST / SPDT / DPDT / Slide / Tactile), Debouncing.

Letter

P

1 term

Pin Headers (2.54 mm, 1×40 breakable, male + female)

Standard 0.1″ pitch single-row pin headers, 40 pins long, breakable to any length. Your kit has 20 male strips and 20 female strips. Practical: Solder a male strip to a breakout board, plug it into a breadboard or female header on a dev board. Watch for: always tin the iron tip before each pin; use a tiny bit of fresh solder on the pin, then heat the pad + pin together for 2 seconds, then flow in a little more solder. Pull the iron straight up; the pin should have a shiny volcano shape when you're done. See also: Soldering Iron (80 W, LCD, 110 V).

Letter

R

3 terms

Raspberry Pi Pico W (RP2040)

A small, cheap, dual-core ARM Cortex-M0+ microcontroller with 264 KB SRAM, 2 MB flash, Wi-Fi (CYW43439), and a USB-C connector. The 'W' adds wireless. Practical: The default MicroPython board. The dual-core is the killer feature: core 0 runs your code, core 1 can run PIO state machines for WS2812B, I²S, custom protocols. Three traps: (1) the on-board Wi-Fi is only enabled in MicroPython if you use the pico-w build (not the regular Pico build); (2) the 3.3 V rail can only supply ~300 mA total — be careful with LEDs and servos; (3) the BOOTSEL button is the only way to flash over USB without a debugger. See also: MicroPython, PIO (Programmable I/O), Raspberry Pi Pico W (RP2040).

Resistor Kit (1/4 W, E12, 10 Ω to 1 MΩ)

A 600-piece assortment of 1/4 W through-hole resistors in 30 E12 values × 20 pieces each. Covers 10 Ω, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82, 100, 120, ... up to 1 MΩ. Practical: The single most-used kit on your bench. Defaults for S3-tutorial work: 220 Ω for LEDs (any color, 3.3 V rail), 1 kΩ for buttons with a pull-up, 4.7 kΩ for I²C pull-ups, 10 kΩ for voltage dividers and pull-ups on 5 V signals, 100 kΩ for RC time constants. Watch for: 1/4 W is plenty for MCU work, but if you build a power supply or motor driver you need 1 W or 2 W parts — they don't fit in the same kit. See also: Resistor Color Code, Ohm (Ω) / Resistance (R), Voltage Divider.

Rosin-Core Solder Wire (63/37, 0.8 mm)

Lead-bearing (63% tin, 37% lead) rosin-core solder, 0.8 mm diameter, 50 g roll. The workhorse solder for through-hole and large SMD work. Practical: 63/37 is eutectic — it goes from liquid to solid at one temperature (183 °C) with no plastic range, so 'cold joints' are harder to make. Lead-bearing is much easier to work with than lead-free (SAC305 melts at 217–227 °C and has a plastic range). Watch for: the 0.8 mm diameter is the right size for general work; 0.5 mm for SMD, 1.0 mm for heavy cables. Lead solder requires washing your hands after use and proper ventilation. See also: Soldering Iron (80 W, LCD, 110 V).

Letter

S

6 terms

SG90 Micro Servo (9 g, 180°)

A tiny hobby servo: 9 g, 1.8 kg·cm torque at 4.8 V, 50 Hz PWM, 180° range, 1.0–2.0 ms pulse width. Practical: The default small servo. Wire colors: orange = signal, red = VCC (5–6 V), brown = GND. Wiring: the signal goes to a PWM-capable GPIO. Watch for: the SG90 draws ~100 mA when moving, ~10 mA when idle, with peaks of 500+ mA at stall — never power from the MCU's 3.3 V or 5 V rail, use a separate supply (a 18650 + boost is fine). The library is simple: angle = map(pulse_us, 1000, 2000, 0, 180). See also: Servo Motor (SG90 / Standard), PWM (Pulse-Width Modulation).

Soldering Iron (80 W, LCD, 110 V)

A temperature-controlled soldering station (iron + base + LCD display). 80 W means it heats up fast and recovers quickly when you solder a big joint. Practical: Set 320 °C for lead solder (63/37), 360 °C for lead-free. Watch for: (1) clean the tip with a brass wool ball (not a wet sponge — that drops the tip temp and oxidizes it); (2) re-tin the tip with fresh solder before putting the iron down; (3) replace the tip every 6 months of regular use. See also: Rosin-Core Solder Wire (63/37, 0.8 mm).

SSD1306 0.96" OLED (I²C, 128×64)

A 5-pack of small white-pixel OLED displays: 0.96″ diagonal, 128×64 resolution, I²C interface at address 0x3C. 3.3 V supply, ~20 mA when on. Practical: The default status display for an MCU project. Library: ssd1306 in MicroPython, Adafruit_SSD1306 in Arduino. Watch for: some clones ship at address 0x3D — run i2c.scan(). The display has no CS pin (I²C only); the reset pin must be tied high or driven from a GPIO for the init sequence to work. See also: I²C (Inter-Integrated Circuit), Address (I²C / SPI), SSD1306 0.96" OLED (I²C, 128×64).

ST7789 2.0" TFT (SPI, 240×320, full-color)

A 2″ diagonal IPS TFT with 240×320 resolution, 16-bit color (RGB565), SPI interface. 8-pin module: VCC, GND, SCL (SCK), SDA (MOSI), RES, DC, CS, BL. 3.3 V supply. Practical: The default full-color display. Performance: with the ESP32-S3's SPI peripheral at 40 MHz, full-screen refresh is ~50 ms. Watch for: the BL (backlight) pin can be PWM-controlled for dimming — drive it through a MOSFET or a GPIO with current limiting (the backlight draws 30–60 mA, too much for a GPIO directly). Use a frame buffer in PSRAM for smooth animations. See also: SPI (Serial Peripheral Interface), Chip Select (CS) / Slave Select (SS).

Solid-Core Tinned Copper Wire (22 AWG, 5 m)

A 5 m roll of 22 AWG solid-core, tin-plated copper wire, PVC-insulated. Practical: For breadboard jumper wires that aren't the pre-crimped Dupont type. Strip the end with a wire stripper (NOT your teeth — you'll regret it), tin with solder, and plug into a breadboard. Watch for: solid-core wire breaks with repeated flexing — for any moving part, use stranded. 22 AWG is good for signals and small power (≤ 2 A); for more, step up to 18 or 16 AWG. See also: Jumper Wire, Ampere (A) / Current (I).

SPDT Mini Slide Switch (1P2T)

A 20-pack of small SPDT slide switches, 4 mm handle, 5 V / 0.3 A rated, 3 pins. Practical: The default power or mode switch. Wiring: the middle pin is COM, the two outer pins are NO (normally-open) and NC (normally-closed). Watch for: 0.3 A is the contact rating — for a project that draws 1 A from a battery, use a switch rated for 3 A or more (or a MOSFET). The 5 V rating is also a limit — a 12 V motor switch is a different part. See also: Switch (SPST / SPDT / DPDT / Slide / Tactile), Debouncing.

Letter

T

3 terms

Tactile Pushbutton (6×6 mm THT)

A small 4-pin tactile switch, 6×6 mm body, ~260 g actuation force, ~50 000 click lifetime, rated 50 mA @ 12 V. Your kit has 1 (in the 37-in-1 KY-004 module) and 4 more on order. Practical: The default user input. Wiring: the 4 pins are 2 pairs — pins 1-2 are connected, pins 3-4 are connected; when pressed, 1-2 connects to 3-4. Use one pair (1-2) as the switch contact, the other pair (3-4) for mechanical stability on the PCB. Always add a pull-up or pull-down — the button is open-circuit when not pressed, and a floating GPIO will give random values. Watch for: mechanical buttons bounce for 1–10 ms — always debounce in software. See also: Switch (SPST / SPDT / DPDT / Slide / Tactile), Debouncing, Pull-up / Pull-down Resistor.

TB6612FNG Dual Motor Driver (1 A)

A dual H-bridge motor driver IC on a carrier PCB. Each channel: 1 A continuous, 3.2 A peak, 1.5–13 V motor supply, 2.7–5.5 V logic. Inputs per channel: IN1, IN2 (direction), PWM (speed), STBY (master enable, all channels). Practical: The default driver for small DC motors and gearmotors in an MCU project. The TB6612 is more efficient than the L298N (no big sense resistors) and smaller. Wiring: 3 boards × 2 channels = 6 motors. Each channel needs 2 GPIO for direction + 1 for PWM = 3 GPIO × 6 channels = 18 GPIO + 1 STBY. Watch for: tie STBY HIGH to enable, never leave it floating. See also: TB6612FNG Dual Motor Driver (1 A), PWM (Pulse-Width Modulation), GA12-N20 Micro Metal Gear Motor.

TMC2209 v1.3 Silent Stepper Driver

A pin-compatible upgrade to the A4988 with silent StealthChop2 chopping, 2.5 A RMS / 2.8 A peak, UART configuration. Practical: The right driver for a project where motor noise matters (audio, video, a quiet room). StealthChop2 is the silent mode — the motor sounds like it's not moving. Watch for: the TMC2209 needs a clean 5 V logic supply (the logic regulator on the A4988 is too weak) — usually 200 mA is enough. Configure via UART once (or just leave the default settings, which work for most projects). See also: A4988 Stepper Driver, Stepper Motor (NEMA 11 / NEMA 17).

Letter

U

2 terms

Universal PCB Protoboard (9×15 cm, 1.2 mm)

A 10-pack of single-sided phenolic PCBs with 2.54 mm hole pitch and standard 1.2 mm thickness. The through-hole pads are connected in long buses, ideal for hand-soldered prototypes. Practical: Cut to size with a hacksaw or score-and-snap. Watch for: 1.2 mm thickness is fine for through-hole parts and small SMD; for larger components (TO-220 regulators, big capacitors) you may want 1.6 mm for mechanical strength. See also: PCB (Printed Circuit Board), Capacitor (Decoupling / Bypass).

USB-TTL Serial Cable (CP2102, 3.3 V)

A 1 m USB to UART cable with the CP2102 chip and a 4-pin Dupont connector: GND (black), TX (green), RX (white), 3V3 (red). 3.3 V logic only. Practical: Used to add a serial console to a board that doesn't have USB (the Raspberry Pi 4 talking to a bare ESP32-S3 module, for example). Watch for: the CP2102 is 3.3 V — DO NOT plug this into a 5 V Arduino's TX/RX, you'll be fine (5 V is 5 V tolerant) but the other direction is 3.3 V. Also: the FTDI FT232 is the other common chip; both work, the CP2102 is usually cheaper. See also: UART (Universal Asynchronous Receiver/Transmitter), Serial (UART).

Letter

V

1 term

12 V 2 A DC Power Supply (barrel jack, 2.1 mm)

A 100–240 V AC wall-wart, 12 V DC at 2 A out, 2.1 × 5.5 mm coax barrel jack, center-positive. 24 W total. Practical: The default bench supply for a 12 V project (the stepper motors, mostly). Watch for: the center-positive convention is universal for 12 V supplies, but the barrel size isn't — 2.1 mm is more common than 2.5 mm. A polarity tester (or a multimeter) is worth the $3 if you have a drawer full of mystery wall-warts. See also: BNC / SMA / USB-C / Barrel Jack, Stepper Motor (NEMA 11 / NEMA 17).

Letter

W

1 term

WS2812B Addressable RGB LED Strip

An 8-LED (or 1 m / 30-LED) strip of individually-addressable RGB LEDs. 5 V supply, 60 mA per LED at full white, single-wire 800 kHz protocol. Practical: The default 'fancy lights' for an MCU project. Wiring: 5 V and GND from a beefy supply (5 V/2 A for 30 LEDs), DIN from a GPIO (3.3 V logic — use a 74HCT125 level shifter for long runs). Watch for: the first LED is dimmer than the last if you daisy-chain and the wire is thin — for a long strip, inject 5 V at both ends. The protocol is timing-sensitive: use PIO (RP2040) or the RMT peripheral (ESP32) to drive it, not bit-bang. See also: RGB LED / WS2812B / NeoPixel, PIO (Programmable I/O), Level Shifter.

Letter

X

1 term

XL6009 DC-DC Buck-Boost Module

A 3-pack of XL6009-based buck-boost converters. 3.8–30 V input, 1.25–35 V output, 4 A peak, 400 kHz switching. Practical: The default supply for a battery-powered project where the input voltage range straddles the output. Classic case: 3.7 V LiPo (range 3.0–4.2 V) powering a 5 V load — when the battery is full it's a buck, when half-discharged it's a boost. Set the output voltage with the multi-turn pot before connecting the load. Watch for: the XL6009 needs solid input/output caps (≥ 22 µF) or it will oscillate. The 4 A peak is real but at 1.5 A continuous the chip needs a heat sink or it'll thermal-limit. See also: Buck-Boost Converter, Buck Converter, Boost Converter.

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6. Quick reference tables

6.1 Inventory status (as of 2026-07-01)

Status	Line items	Approximate cost
RECEIVED (in hand, tested)	27	~C$130 + 4 Temu (no price) + 4 bench stock
AWAITING (paid, shipping)	7	~C$47
PLANNED (S3 tutorial gap-fill)	6	~C$6
PLANNED (weaver BOM)	11	~$67 USD
CANCELED / REFUNDED	2	C$10.63 credited
Total	53 distinct lines (4 stubs excluded)	~C$200 + USD 67

6.2 I²C address cheat sheet (your kit)

All of these go on the same SDA/SCL bus. Watch for address collisions — two devices on the same address will silently corrupt each other's reads.

Part	Default addr	Alt addr	How to switch
MPU-6050 IMU	0x68	0x69	AD0 pin (solder bridge on GY-521)
BMP280 (pressure)	0x76	0x77	SDO pin (solder jumper on most boards)
AHT20 (T/RH)	0x38	—	fixed
SSD1306 OLED	0x3C	0x3D	some clones only; check with i2c.scan()
PCF8574 (port expander)	0x20–0x27	—	A0–A2 jumpers (3 bits = 8 addrs)

6.3 Power tree (what supplies what)

Source	Voltage	→	Regulator	→	Rail	Feeds
USB-C (5 V)	5.0 V	→	on-board LDO	→	3.3 V	ESP32-S3, MPU-6050, AHT20, BMP280, SSD1306, INMP441, ST7789, KY-* kit, sensors
USB-C (5 V)	5.0 V	→	(direct)	→	5 V	DFPlayer Mini, MAX98357A, HC-SR04 (with level shift on Echo)
18650 cell	3.0–4.2 V	→	MT3608 boost	→	5.0 V	DFPlayer, MAX98357A, WS2812B, any 5 V load
18650 cell	3.0–4.2 V	→	XL6009 buck-boost	→	adjustable	anywhere you need stable 3.3 V, 5 V, 9 V, 12 V from a battery
12 V wall-wart	12.0 V	→	Mini360 buck	→	3.3 V / 5 V	3.3 V logic, 5 V sensors
12 V wall-wart	12.0 V	→	(direct)	→	12 V	A4988 / TMC2209 VMOT (NEMA 11 steppers)

6.4 Crimp cheat sheet

Connector	Pitch	Use for	Tool
Dupont (M/M, M/F, F/F)	2.54 mm	breadboard jumpers	pre-crimped (just buy)
JST-PH	2.0 mm	LiPo balance, sensor cables, small DC	SN-28B or Engineer PA-09 crimper
JST-XH	2.5 mm	LiPo balance leads (≥ 3S)	SN-28B
JST-SM	2.5 mm	3.7 V single-cell LiPo (BEC plugs)	SN-28B
XT30 / XT60	n/a	high-current battery (drone, e-bike)	solder (don't crimp)
Barrel jack	2.1 / 2.5 mm	wall-wart DC power	solder

6.5 Wiring rules (the 10 commandments of bench prototyping)

Color-code: red = power, black = ground, one color per signal. You will save hours.
Power first, signal second. Connect 3.3 V and GND to the board before plugging in USB. Verify with a multimeter.
One rail per breadboard row. Don't daisy-chain power through components; use the red and blue rails.
Decoupling on every IC. 100 nF ceramic, as close to VCC as you can physically place it.
Pull-ups on open-drain lines. I²C, Hall sensor, anything that says "open-drain" in the datasheet.
Keep wires short. < 15 cm for signal wires on a breadboard. The capacitance and noise pick-up go up fast.
Don't share ground through the breadboard. Use a star ground: a single point where everything's GND meets. The breadboard's rails are fine for that point.
Measure before you connect. Voltage on the rail, resistance of the pull-up, capacitance of the cap. The 30 seconds it takes saves the 30 minutes of debugging a fried part.
One new thing at a time. Add a sensor, test it. Add a driver, test it. Add Wi-Fi, test it. If you add three things and it doesn't work, you have three bugs.
Photograph your wiring. Before you tear it down, take a picture. You'll rebuild it in three weeks and won't remember which wire went where.

6.6 When it doesn't work (the 4-step recovery)

Smell it. A hot component or burnt smell is a real signal. Power down immediately.
Look at it. Solder bridges, reversed LED, missing wire, swapped SDA/SCL — 70% of beginner bugs are visible.
Measure it. 3.3 V at the rail? 5 V at the wall-wart? Continuity on every wire?
Reduce it. Comment out half the code. Disconnect half the circuit. The bug is in the half that, when removed, makes the problem go away.

If still stuck after the 4 steps, ask a colleague. Describe what you tried first, then the symptom — not the other way around.

7. Further reading

Start here (free, high quality):

🔥 MicroPython for the ESP32-S3 — docs.micropython.org
🔥 Adafruit sensor learning guides — learn.adafruit.com (search by part number)
🔥 Sparkfun tutorials — learn.sparkfun.com
📚 Espressif ESP32-S3 forum — esp32.com
📚 Phil's Lab (YouTube, deep dives on Altium + motors + STM32) — best embedded YouTube

Companion documents in this lab:

Electronics Concepts Quick Reference — the sister glossary (concepts, not parts)
ESP32-S3 Development Primer — ~/MicroController/projects/PRIMER.md
Hardware Inventory — ~/MicroController/projects/HARDWARE_INVENTORY.md (the canonical spreadsheet-style source of truth)
esp32s3-micropython tutorial series — ~/projects/esp32s3-micropython/ (ES01–ES07 exercises that use these parts)

Datasheets (open the actual PDF for any part you're wiring):

ESP32-S3 — espressif.com
RP2040 / Pico W — datasheets.raspberrypi.com
MPU-6050 — invensense.tdk.com
TB6612FNG — Toshiba datasheet, freely available
A4988 / TMC2209 — Allegro / Trinamic PDFs

Last updated: July 2026. Maintained as a living document — if a term on your co-op isn't here, add it.