Circuits, microcontrollers, sensors, and embedded firmware.
Tool ·
How a brushless motor works and how an ESC drives it: Kv, Kt and flux linkage in every convention, torque–speed and efficiency maps, heating, measuring a motor yourself, slot/pole windings drawn with their pattern and winding factor, six-step with Hall sensors and sensorless zero crossings, Clarke/Park, FOC current loops, SVPWM, field weakening, inverter losses, DShot frames and eRPM telemetry — animated and simulated.
Exploration ·
Start with one transistor switching an LED, wire switches into gates, gates into an adder, feedback into memory, and memory plus a clock into a tiny CPU — then watch a real 6502 run a program you can read byte by byte.
Exploration ·
From magnets and coils to a quadcopter in the air: how a brushless motor is wound, how an ESC switches it in six steps, how it finds the rotor without sensors, what field-oriented control does better, and what happens when you bolt four of them to a frame — with the simulators running alongside.
Tool ·
Wire a car, van, truck or motorbike: cable size in mm² and AWG from the current, the round-trip length and the voltage drop you allow, with insulation rating, under-bonnet heat and bundling; the fuse that protects it; relay circuits drawn as schematics with the 30/85/86/87/87a pins and the flyback diode; crimp terminals and connectors; parked battery drain and the alternator's load; a second battery on a DC-DC charger; and the DIN 72552 terminal numbers.
Tool ·
Type a transaction (bytes, addresses, read or write) for SPI, I²C, UART, 1-Wire, SD card SPI-mode init or JTAG and get a zoomable, animated timing diagram with every phase labelled. Step through it bit by bit with an explanation of each one, inject errors to see how a decoder reacts, or paste a capture and decode it.
Tool ·
Hand-assemble a KiCad board from its .kicad_pcb: the BOM grouped by value and footprint with placed and sourced ticks, the parts of the row you are on lit up on front and back drawings (click a part to find its row), side and DNP filters, progress kept per board, keyboard-driven, stock and bins from your Parts inventory, and a standalone HTML copy to keep with the board.
Tool ·
Open a KiCad board (.kicad_pcb, KiCad 6–9) in the browser and look round it — every layer toggled, tracks, vias, zones, pads and footprints drawn as KiCad places them, the back seen from underneath, a net lit up with a click (its pads and track length), measure, find a part, board facts with the smallest clearance, export the visible layers as SVG or PNG, and send the outline to the enclosure maker.
Tool ·
Open KiCad footprints (.kicad_mod, a whole .pretty folder) and symbol libraries (.kicad_sym), see each footprint's pads, courtyard, fab and silkscreen drawn, and get a list of problems with a severity and a one-line reason — courtyard, pin 1, silk on pads, holes and annular rings, paste, origin, naming; and for symbols off-grid and overlapping pins, duplicate numbers, power pin types, hidden power pins, reference, footprint and datasheet fields.
Tool ·
Time on air for any LoRa packet, LoRaWAN data rate or Meshtastic preset, and what it means: messages per hour under the EU duty-cycle sub-bands, the US 400 ms dwell time and TTN's fair-use policy, sensitivity and range per spreading factor, an airtime chart and a battery estimate.
Tool ·
Decode a LoRaWAN PHYPayload — join requests and accepts, uplinks and downlinks with every FHDR field — check the MIC, decrypt the payload with your session keys, decrypt join accepts and derive the session keys, read MAC commands, and decode CayenneLPP.
Tool ·
Decode Meshtastic packets from hex, base64 or a live MQTT feed — ServiceEnvelopes, MeshPackets, Data and raw over-the-air frames — decrypting channel traffic with your keys, with a byte-by-byte field view and a list and map of the nodes heard.
Tool ·
Compose PS/2 keyboard and mouse traffic, WS2812 pixel data, IR remote codes (NEC, RC5, RC6, Sony), DMX512 packets, MIDI bytes and Centronics printer handshakes, and step through the timing diagram bit by bit — with error injection, decoders for pasted captures and Flipper/IRremote files, VCD export and a hand-off to the logic analyser.
Tool ·
Turn KiCad's position file (or the .kicad_pcb itself) and BOM into the placement file JLCPCB, PCBWay or Seeed want — the right columns, mm or inches, top/bottom naming, origin, bottom-side mirroring, an editable table of per-footprint rotation offsets, DNP left out — with a drawing of every part and its pin 1, and a JLCPCB BOM with LCSC numbers from a field or your Parts inventory.
Tool ·
Turn a Raspberry Pi Pico (or an ESP32) running stock MicroPython into a bench tool driven from the browser — GPIO and PWM, an I²C scanner with register reads, SPI with flash JEDEC ID decoding, a UART bridge, 1-Wire thermometers, a live ADC plot, a PS/2 keyboard sniffer, and a PIO logic capture that opens in the logic analyser. No custom firmware.
Tool ·
Write Cortex-M assembly and step through it on a simulated microcontroller: a GNU-syntax assembler for Thumb and Thumb-2 with literal pools and IT blocks, every 16- and 32-bit encoding split into its fields bit by bit, registers and NZCV with changes highlighted, memory and stack views, breakpoints, LEDs and switches on GPIO, a UART terminal, SysTick interrupts through a vector table, and Cortex-M0 or M3 cycle counts.
Tool ·
Available fault current by the point-to-point method — transformer or utility figure, then conductor runs — with the formulas shown, motor contribution, and a check against equipment ratings (110.9, 110.10, 110.24).
Tool ·
Count a box's fill the NEC 2023 way (314.16): pick a metal box from Table 314.16(A) or enter a plastic box's marked volume, add conductors by size, loops, clamps, studs, devices and grounds with big +/− buttons, and see the cubic inches needed against the box, with a bar and the boxes that would fit.
Tool ·
For your flying fields: the hourly forecast — wind and gusts at 10 m and the wind at 80 and 120 m, rain, cloud and an estimated cloud base, visibility, temperature — and the geomagnetic Kp index, judged against each aircraft's limits as a go / marginal / no timeline for 48 hours or 7 days, with the reasons, the best windows and the runway crosswind.
Tool ·
Conduit bending marks for offsets, rolling offsets, saddles, 90° stubs, back-to-back 90s, kicks, segment bends and parallel offsets — drawn to scale, in inches to 1/16, with the 360° rule between pull points.
Tool ·
Conduit fill by NEC 2023 Chapter 9: choose the raceway (EMT, IMC, RMC, PVC 40/80, ENT, FMC, LFMC, LFNC…) and add conductors by insulation and size — the fill against 53, 31 or 40 % (60 % for a nipple), the smallest trade size of each type, a drawing of the cross-section, the jam ratio for three conductors, and an Annex C-style table of how many fit.
Tool ·
Enter a plant as a transfer function — polynomials or poles, zeros and gain, continuous or sampled — or pick a DC motor, mass–spring–damper, inverted pendulum, thermal or dead-time preset, add a P, PI, PID or lead/lag controller, and see the step and impulse responses with rise, overshoot, settling and steady-state error, the Bode plot with gain and phase margins, the Nyquist plot, a root locus you drag the gain along, and the closed-loop pole–zero map, with Ziegler–Nichols, IMC and SIMC tuning.
Tool ·
Design FIR (windowed sinc, Parks–McClellan, frequency sampling) and IIR (Butterworth, Chebyshev I/II, elliptic) low-, high-, band-pass and band-stop filters for a sample rate, with the order estimated from your ripple and attenuation; see magnitude, phase, group delay, poles and zeros, impulse and step; round the coefficients to Q15/Q31 to see what breaks; export C, CMSIS-DSP and scipy code; and listen to it running on noise, a sweep, your microphone or a file.
Tool ·
What service a one-family house needs under NEC Article 220: standard and optional methods, an existing house adding an EV charger or heat pump, the neutral, and a printable step-by-step worksheet like the Annex D examples.
Tool ·
How long a charge takes and what it costs — Level 1, Level 2 or DC fast with a taper curve, the car's on-board charger limit, losses, flat or time-of-use prices — the range it adds per hour, the cost per mile against petrol, and the home charger circuit: 125 % breaker, wire size and receptacle under NEC 2023.
Tool ·
A searchable phone cheat sheet: US wire colours (incl. 277/480 V), NEMA receptacle faces and ratings, GFCI and AFCI locations, working space, breaker/wire pairings and torque.
Tool ·
Choose 5.8 GHz video channels for a group of pilots — analogue bands, HDZero, DJI and Walksnail — keeping them apart and away from intermodulation products, with a frequency table and a range estimate for video and ExpressLRS links.
Tool ·
Plan a quad build (all-up weight, thrust-to-weight, hover throttle, flight time, prop clearance), compare and convert Betaflight rates and test them with your transmitter, diff two Betaflight CLI dumps into a script, and open a blackbox log to plot gyro, PIDs and motors with a noise spectrum.
Tool ·
List what must run in an outage — fridge, well and sump pumps, furnace, AC and heat pump by tonnage, EV charger, lights, tools — with running watts and starting surge from the code letter or locked-rotor amps (and soft starters); find the start order with the lowest peak, the generator size after derating for altitude, heat and fuel, fuel per hour and runtime from your tank, leg balance, and what NEC 702 asks of the transfer switch.
Tool ·
Size the grounding and bonding conductors by NEC 2023 Article 250: the equipment grounding conductor from the breaker (Table 250.122, upsized in proportion when the hots are upsized), the grounding electrode conductor from the service conductors (Table 250.66) with the rod, concrete-encased and ring limits, and the main, system and supply-side bonding jumpers (Table 250.102(C)(1) and the 12.5 % rule) — each with what it does and why.
Tool ·
Tune a Kalman filter live and watch it work — a 1-D value, 2-D tracking with constant-velocity and constant-acceleration models, an extended Kalman filter for a range–bearing sensor, GPS + accelerometer fusion, and complementary filter against Kalman for tilt (with your phone's sensors) — stepping through predict and update with every matrix shown, covariance ellipses, innovations and NIS/NEES consistency against chi-square bounds.
Tool ·
Keep a register of your LiPo packs — cells, capacity, C rating, chemistry, age, cycles, and internal resistance over time on a chart — with a quick log after each charge or flight, warnings for rising IR, out-of-balance cells, old and puffed packs, calculators for charge current and time, storage voltage, parallel charging and airline watt-hour limits, and QR labels that open a pack's record.
Tool ·
Size a motor circuit by NEC Article 430: full-load current, conductors, breaker or fuses by Table 430.52, overloads, disconnect, grounding conductor, starting kVA and voltage dip, a feeder for several motors, and a one-line summary card.
Tool ·
Plug an ELM327 adapter into the car and read it from the browser over Bluetooth LE or USB — live gauges and graphs with CSV logging, stored, pending and permanent trouble codes with descriptions, the freeze frame, readiness monitors, the VIN, and clearing codes — or try it all on a simulated car.
Tool ·
Size a stand-alone solar system from a list of what you run — cabin, van, boat or tiny house — and your location's month-by-month sunshine (Open-Meteo, or your own peak sun hours): the PV array for the worst month or the year, how to string the modules (cold Voc under the controller's limit, NEC 690.7; 1.25 × Isc, 690.8), MPPT or PWM, the LiFePO4 or lead-acid bank in series and parallel, the inverter, a month-by-month balance with generator hours, and a single-line diagram.
Tool ·
Lay out and balance a 120/240 V, 208Y/120 V or 480Y/277 V panel: circuits, poles and breakers, per-phase VA, amps and neutral, imbalance, demand against the main, checks, and a printable schedule or CSV.
Tool ·
Pinion and spur to final drive ratio, rollout and theoretical top speed from Kv or motor turns; a pinion × spur table with a target highlighted; gear mesh centre distance against the motor-mount slot; shock oil, diff oil and spring rate conversions; and setup sheets per car that you can compare, export and print.
Tool ·
Work out what a motor, propeller and LiPo will do together — RPM, current, voltage sag, power, efficiency, static thrust, pitch speed, thrust-to-weight, hover or cruise throttle and flight time — with warnings for the motor, ESC and battery, a throttle sweep chart and up to three setups side by side.
Tool ·
Write RV32IM assembly and step through it: an assembler with pseudo-instructions and %hi/%lo, the machine code beside each line with every format's fields decoded bit by bit, registers with changes highlighted, memory and stack views, breakpoints, RARS-style ecalls, LEDs and switches on a memory-mapped device, and a 5-stage pipeline diagram of what ran, with stalls, forwarding and flushes.
Tool ·
Plan the 12/24/48 V side of a camper van, RV or boat: wire size by voltage drop (3 % critical, 10 % non-critical, ABYC E-11 style) and ampacity with engine-room and bundling derates, the fuse that protects it and how close to the battery it must sit, a battery bank in series and parallel with balanced wiring and the main fuse its short-circuit current needs, alternator DC-DC and shore chargers, a busbar and fuse-block layout, and a daily amp-hour budget.
Tool ·
Servo arm, horn and hinge offset → surface throw in degrees and mm at the trailing edge (solved exactly, with a linkage drawing), and the arm or horn for a target throw; end points, rates and expo curves; elevon, V-tail, flaperon and crow mixes shown live from sliders or a USB transmitter; and the servo torque a surface needs.
Tool ·
Design a loudspeaker enclosure from a driver's Thiele/Small parameters — sealed, vented (QB3, B4, BB4, C4 or your own tuning) or 4th-order band-pass — with SPL, cone excursion against Xmax, group delay, impedance and port air speed plotted, the port length worked out, and the box turned into panel sizes and a cut list.
Tool ·
A polyphonic subtractive synthesizer in the browser — three oscillators with pulse-width modulation, noise and unison, a resonant 12 or 24 dB filter with its own envelope, two LFOs, glide and mono legato, distortion, chorus, delay and reverb, an arpeggiator, 26 original presets, and an "explain" mode that says what each section does. Play it on screen, from the computer keyboard or a MIDI keyboard.
Tool ·
Polar alignment (where Polaris or σ Octantis sits on your polar-scope reticle right now, and drift alignment), setting circles (RA/Dec to altitude and azimuth and back, hour angle, sidereal time), and a GoTo controller over Web Serial for Celestron NexStar, Sky-Watcher SynScan and Meade LX200 mounts — connect, read where it points, slew, sync, nudge and stop. It refuses to slew near the Sun.
Tool ·
Transformer kVA and amps, 450.3(B) protection, 240.21(C) secondary conductors, buck-boost selection with a wiring diagram, delta/wye and the high-leg delta, and the power triangle with PF correction.
Tool ·
The smallest US conductor (NEC 2023) for a load, rule by rule — 125 % of continuous load at the terminations, ambient and bundling corrections, the breaker it must be protected by, the 14/12/10 AWG limits, parallel sets — and voltage drop by the K-factor or Chapter 9 Table 9 method, with the rule that governs highlighted. Or the reverse: what a given wire will carry and how far.
Tool ·
Connect several Bluetooth sensors at once — heart-rate straps, power meters, speed and cadence sensors, running pods, smart trainers, thermometers, Xiaomi LYWSD03MMC, scales — with big live numbers and graphs, one timeline logged in the browser and exported as CSV, and ERG workouts and free rides on an FTMS trainer.
Tool ·
Write effects for the Boing Ball lamp in JavaScript, the way the firmware's are written — render(ctx, out) over the lamp's 128 cells — watch them on a 3-D ball with the lamp's real cells and on a flat map, stream them to the lamp over Bluetooth, or run them as a full-screen screensaver that shuffles the effects and bounces the ball.
Tool ·
Control the Boing Ball lamp from the browser over Bluetooth — the lamp's own control page (effects, brightness, playlist, clock and weather, LED calibration, WiFi set-up) with every request carried over BLE, plus a console for its text commands.
Tool ·
Lay out LED strips, frames, rings and matrix panels in millimetres, watch patterns run on them, and get the current, supply, voltage drop and power injection points, feeder wire and fuses, data outputs and frame rate — then export a WLED ledmap and segments, ESPHome YAML, a FastLED XY map and a bill of materials.
Tool ·
Design labels from templates — title, text and QR codes with captions, big text, bins and drawers, barcodes, asset tags, cable flags, Wi-Fi, if-found, food dates, filament spools, warnings, addresses — see them dot for dot, number a run or paste rows from a spreadsheet, and print straight to a Niimbot label printer over Bluetooth or USB.
Tool ·
Watch every message on your MIDI ports decoded (notes, controllers, programs, pitch bend, clock and BPM, MTC, SysEx with the maker's name and identity replies), play a keyboard with wheels and assignable sliders, send raw bytes and SysEx files, and program a 16-step drum or melodic sequencer — with a built-in synth when there's no device.
Tool ·
Print to-do lists, shopping lists, notes, job cards, daily agendas, recipes, Wi-Fi guest cards, pictures and free-form receipts on a cheap thermal printer — ESC/POS 58 and 80 mm printers over USB, serial or Bluetooth, and the little Bluetooth "cat printers" — with a dot-for-dot preview of the paper strip.
Tool ·
Plan a workshop's circuits — US 120/240 V split-phase or UK/EU 230/400 V three-phase — with breakers, wire and run lengths, and the machines on each (table saws, dust collectors, compressors, welders, kilns, lasers, 3-D printers, heaters, lights): what can run at once under the 80 % continuous rule, which motor starts will trip the breaker, voltage drop running and on start, three-phase currents, and a load schedule to print. A planning aid, not a substitute for an electrician.
Tool ·
Design a wire harness — connectors from a library of common families (JST, Dupont, Molex, Deutsch DT, XT30/60/90, M8/M12, RJ45, D-sub, screw terminals), wires with colours, gauges, lengths, pairs and shields, splices and sleeves — and get the WireViz-style diagram, pin-outs with face views, a BOM with housings and crimp terminals, a cut list, a voltage-drop check, and cable flags for the label maker. Imports and exports WireViz YAML.
Tool ·
Android Debug Bridge in the browser — over WebUSB or the network (port 5555 through the gitwebsite app): device info, logcat, a shell, APK install, apps, files, screenshots and recordings, and a TV remote for Fire TV and Android TV.
Tool ·
How long a microcontroller project runs on its battery — a duty cycle built from datasheet currents for the ESP32, ESP32-C3, ESP32-S3, nRF52840 and RP2040 (each cited to its table), capacity derating for temperature, ageing and cut-off, self-discharge, and an LDO's quiescent current or a switcher's efficiency — with a one-cycle current timeline, where the charge goes, and what-ifs.
Tool ·
Decode FT8, PSK31, RTTY, CW and SSTV from a microphone, line-in, an audio file or the SDR receiver — FT8 with UTC slot timing, SNR, DT and frequency; make PSK31, RTTY and SSTV audio; and map WSPR and PSK Reporter spots for a callsign.
Tool ·
A searchable electronics quick reference — Ohm's law to op-amps, filters, biasing and the diode equation, each with a calculator; E series, wire gauge with NEC ampacity, IPC-2221 trace current and clearances, logic levels, IC pinout drawings, decoupling, batteries, connectors and schematic symbols — plus a MOSFET/BJT switch calculator.
Tool ·
Import your smart-meter data (Green Button XML or CSV, Octopus, Home Assistant, or any interval CSV) in the browser; see every hour as a heatmap, daily and monthly use, baseload and peaks; price it on flat, tiered and time-of-use tariffs you can edit; and try an EV, a heat pump, solar and a battery against your own hours.
Tool ·
Turn a KiCad schematic (.kicad_sch with its sub-sheets), XML netlist or BOM CSV into a rollup for N boards: grouped by value and footprint or MPN, plus attrition and spares, checked against your Parts inventory stock, priced at Digi-Key with price breaks, and exported as a Digi-Key order CSV.
Tool ·
Connect to a Meshtastic node over Bluetooth or USB to see its nodes, telemetry, channels and config and send messages; decode and make channel URLs and QR codes; plan LoRa links for every modem preset with a terrain profile; simulate flooding through a mesh; and map nodes from MQTT.
Tool ·
The greyline on a world map now or at any time, solar flux and Kp from NOAA, a simple MUF and band-opening estimate for a path, beam heading and distance, an ADIF logbook with dupe checks, statistics, a contact map and POTA/SOTA activations, and APRS — decoded from packets, KISS or a live APRS-IS feed — on a map.
Tool ·
Design a reflow profile from editable zones and check it against the solder paste's window (SAC305 from Indium8.9HF's data sheet, Sn63Pb37 from Kester EP256's) and the J-STD-020E limits for your most sensitive package — ramp, soak, time above liquidus, peak and cooling — on a plot; overlay and compare oven thermocouple logs, and export JSON or CSV.
Tool ·
A software-defined radio in the browser — an RTL-SDR dongle over WebUSB, an rtl_tcp server, a recorded IQ file or a built-in test band — with a spectrum and waterfall, click-to-tune, WBFM, NBFM, AM, USB, LSB and CW, squelch, band presets, bookmarks, and audio and IQ recording.
Tool ·
Home Assistant from the browser (entities and history, a service caller built from each service's schema, a template tester, the event bus), an automation YAML linter and explainer, Shelly, Tasmota and Hue controls, and a Matter setup-code decoder and encoder.
Tool ·
A phone-sized remote for LG webOS (SSAP and its pointer socket), Roku (External Control Protocol) and Samsung Tizen TVs on your network — apps, inputs, volume, text entry and toasts — plus developer-mode notes for each.
Tool ·
Anodizing and electroplating numbers: current from current density and the part's area, anodizing time by the 720 rule and a Faraday estimate, Type II / III ranges, dye and seal notes; plating mass, thickness and time by Faraday's law for copper, nickel, zinc, tin, silver and gold; surface area from simple shapes or an STL — with the safety notes, and no cyanide.
Tool ·
Build digital circuits by dragging gates, switches, clocks, LEDs and 7-segment displays, watch the signals light up, and go further with flip-flops, counters, adders, an ALU, RAM and ROM, your own sub-circuits, truth tables with minimised expressions, expression-to-circuit, a timing diagram with real gate delays, and a tiny CPU that runs a program.
Tool ·
A private electronics parts inventory in your browser — scan Digi-Key, Mouser and LCSC bag labels with the camera, identify chips, boards, modules and code-less parts from a photo — by their markings or how they look (on your device), import orders, carts and KiCad BOMs, search by value ("10k 0603 1%"), plan builds for N boards, and get per-supplier purchase lists with price breaks; with storage locations, QR labels printed on sheets or straight to a Niimbot label printer, photos, and optional Digi-Key/Mouser/Nexar API lookups.
Tool ·
Setup/hold slack with a timing diagram, clock-domain crossing patterns with Verilog and synchroniser MTBF, iCE40 and ECP5 PLL settings that match icepll and ecppll, FIFO depth, VESA/CTA-861 video timings with a Verilog generator, UART divisors, BRAM/DSP counts, parallel CRC and LFSR generators, and pin-constraint files for eleven boards.
Tool ·
Write Verilog, simulate it with Icarus Verilog, synthesise with Yosys and build a bitstream for Lattice iCE40, ECP5, CrossLink-NX, MachXO or Gowin FPGAs — or synthesise for Xilinx and Intel and export a Vivado or Quartus project — with the real open-source FPGA tools in your browser, and 44 documented examples.
Tool ·
Live aircraft near you or any airport — on a map or an offline radar scope, in a sortable table, and as an "overhead now" list — from public ADS-B feeds or your own receiver's aircraft.json, with trails, altitude colours, emergency-squawk alerts and a watchlist.
Tool ·
Open a zip of Gerbers and drill files, see the copper, mask, silkscreen, paste and outline stacked or as a realistic top or bottom board, measure, and check the design against JLCPCB, PCBWay or OSH Park's published limits — trace width, spacing, drills, annular rings, edge clearance, mask slivers, silk on pads — with every problem marked on the board.
Tool ·
Learn Verilog by writing it: 23 lessons from gates to UARTs, VGA timing, FIFOs and pipelines, each checked by a hidden testbench that simulates your module and shows the waveform and every mismatch — plus a sandbox simulator and a logic-sim → Verilog converter.
Tool ·
Gaussian beams (waist, Rayleigh range, divergence, w(z), R(z), Gouy phase, M²), focusing to a spot and beam expanders, ABCD q-parameter propagation through a train of lenses with an animated full-screen envelope plot, two-mirror cavity stability on the g₁g₂ diagram, fibre NA, V number, modes, cutoff and Marcuse mode field diameter, a dB link budget, modal and chromatic dispersion, approximate laser-safety MPE and NOHD, and photon arithmetic.
Tool ·
Mechanisms you can play with — an animated four-bar linkage with the Grashof check, its type, the coupler curve and the transmission angle; slider-cranks with stroke and quick return; disc cams with uniform, harmonic, cycloidal and 3-4-5 motion, pressure angle and undercut check; a 2- or 3-link robot arm you drag by the hand, with both inverse-kinematics solutions; and differential-drive kinematics and odometry for small robots.
Tool ·
Decode 1090 MHz Mode S and ADS-B messages field by field — CRC and parity, callsign, altitude, CPR positions with the maths shown, velocity, Gillham codes and Comm-B — from pasted hex, AVR or Beast frames, or live from your receiver over a WebSocket.
Tool ·
Size the moving parts of a printer, CNC or robot — closed-loop and open timing belts (GT2/GT3/HTD/T5/MXL), lead and ball screws (efficiency, back-driving, torque, critical speed, buckling), DC motors and gearbox ratios from Kt/Kv and stall figures, hobby servo torque at an arm, and whether an axis will move at your acceleration.
Tool ·
Printable parts from a few numbers — Gridfinity bins and drawer-filling baseplates to the spec, PCB enclosures from a size or a KiCad / DXF outline (standoffs, snap / screw / sliding lids, USB-C, RJ45 and other cut-outs, vents, lid text), knobs for D, knurled and round shafts, ISO and UNC/UNF threads with print clearance, nuts, bolts and screw-lid boxes — previewed in 3-D and exported as STL, 3MF or STEP.
Tool ·
Identify a tiny part from the code printed on it — a cited list of common SOT-23, SOD and SMA transistor, MOSFET and diode markings with pinout drawings, EIA-96 and 3- / 4-digit resistor codes, and ceramic, EIA two-character and tantalum capacitor codes.
Tool ·
Log a sensor for a science project from an Arduino, ESP32, Pico or micro:bit over USB (Web Serial) or Bluetooth, or from a simulated source: CSV, name:value, JSON and Serial Plotter lines plotted live with zoom and scroll, markers, per-channel statistics, units and calibration, the sample rate, recordings saved in your browser, CSV/JSON export, and example programs to copy.
Tool ·
Predict passes of the ISS and amateur satellites over your location, with AOS, maximum elevation and LOS times, a sky plot, and Doppler-corrected uplink and downlink frequencies.
Tool ·
Starting dimensions for half-wave dipoles and inverted-Vs, quarter-wave verticals and ground planes, J-poles, Moxon rectangles (W4RNL's equations), a 3-element Yagi and the end-fed half wave — with harmonic checks against the amateur bands and turns for 1:1 to 64:1 baluns and ununs.
Tool ·
Convert between SWR, reflection coefficient, return loss, mismatch loss and reflected power; work out coax loss for RG-58, RG-8X, RG-213, LMR-240/400/600, Ecoflex 10, Aircell 7 and RG-6 at any length and frequency, including the extra loss from SWR and the SWR the transmitter sees; and electrical lengths for stubs and phasing lines.
Tool ·
Look up any frequency in the ITU, US, UK, and IARU Region 1 band plans; find a callsign's country, zones, and beam heading; convert Maidenhead locators and work out distance and bearing; and check repeater offsets, CTCSS and DCS tones, Q-codes, and phonetics.
Tool ·
Design L-networks (both topologies, both solutions), Pi and T networks for a chosen Q, single shunt-stub matches and quarter-wave transformers for any load, with component values at the frequency, the loaded Q and bandwidth, and a check of the resulting input impedance.
Tool ·
Learn Morse with the Koch method and Farnsworth spacing, send text as sound or a flashing light, and decode CW from the microphone or an audio file in the browser.
Tool ·
Design Butterworth and Chebyshev LC ladder filters (low-pass, high-pass and band-pass) with the order for your stop-band spec and the response computed from the component values, and resistive attenuator pads — Pi, T, bridged-T and minimum-loss — with the power in each resistor and the nearest standard values.
Tool ·
An interactive Smith chart: plot a load (or click to place one), add series and shunt inductors, capacitors and resistors, lengths of line and stubs, and watch the impedance move towards the centre — with the admittance grid, the VSWR circle, a table of every point and CSV/JSON export.
Tool ·
Work out effective bits from SINAD or measured noise, build a worst-case and RSS error budget from the reference, gain, offset, INL, and divider tolerances, check whether a divider settles the ADC's sample capacitor in time, and plan oversampling.
Tool ·
A live oscilloscope for your computer's audio inputs — triggered scope with cursors and measurements, XY (Lissajous), spectrum and spectrogram, and a tuner — plus a monitor to listen to the input and a two-channel signal generator for loop-back tests. Audio never leaves the page.
Tool ·
Design a lithium battery pack — 18650, 21700, 26650, LiFePO₄ prismatic, or pouch cells in series and parallel (4S2P…) — with its voltage range, capacity, energy, continuous current, weight and size, the BMS and fuse it needs, and the resistance and heating of the nickel-strip links.
Tool ·
Capacitor energy and charge, rectifier ripple and hold-up sizing, supercapacitor backup time, MLCC DC-bias derating, ESR heating and electrolytic life, series stacks with balancing resistors, a comparison of capacitor types — and |Z| and phase of real capacitors, inductors, and resistors, LC tanks, and decoupling networks.
Tool ·
Design and analyse air-core coils (Nagaoka with Rosa's round-wire correction, and Wheeler), multilayer coils, and toroids from their AL value — with turns for a target inductance, wire resistance, skin effect, Q, self-resonance, peak flux, and stored energy.
Tool ·
Pin-outs for over 100 connectors, each with its source — modern ones (USB-C with CC resistor values, RJ45 and PoE, RS-232, SWD/JTAG, VGA, HDMI, TRRS, Qwiic, OBD-II) and retro computer ports: Amiga Zorro and CPU slots, floppy, video, serial and keyboard; Atari 8-bit SIO, PBI and cartridge; Atari ST ACSI, MIDI and cartridge; C64 expansion, user and IEC ports; the Apple II slot, ZX Spectrum, MSX, BBC Micro, NES/SNES/Mega Drive pads, SCART, ISA, IDE and floppy.
Tool ·
Size the load capacitors for a microcontroller's crystal from its load capacitance and the board's stray capacitance, estimate the frequency error of the capacitors you fit, and check the oscillator's gain margin and the crystal's drive level.
Tool ·
Choose a current-sense shunt (drop, power rating, error), the gain of a current-sense amplifier into an ADC (INA180 A1–A4), the INA219's calibration register and LSBs, and scale a Hall-effect sensor such as the ACS712.
Tool ·
Convert levels between dBm, dBW, dBV, dBu, dBmV, dBµV, watts, and volts (rms, peak, peak-to-peak) at any impedance; turn decibels into power and voltage ratios; and cascade gain, noise figure, and IP3 through a receiver chain to get its sensitivity and dynamic range.
Tool ·
Flash, erase, verify, and back up ESP8266 and ESP32-family chips from the browser over Web Serial — offsets from file names or an ESP-IDF build folder's flasher_args.json, merged images, security state, region erase and read-back.
Tool ·
Work out a brushed DC motor's stall and running current, the PWM current ripple for sign-magnitude and locked-antiphase drive, the PWM frequency you need, the H-bridge's conduction, switching and dead-time losses, and what coasting, braking and plugging do.
Tool ·
Pick the devices on an I²C bus and see the 7-bit address map with clashes and reserved addresses, the address-pin strapping that makes them fit, and a TCA9548A multiplexer plan when they can't share one bus — for 53 common sensors, displays, expanders, ADCs, RTCs and EEPROMs.
Tool ·
Arrange LEDs in series strings with ballast resistors and compare every arrangement, weigh resistors against LM317, two-transistor, and switching constant-current drivers, and plan PWM dimming with gamma-corrected brightness tables for your code.
Tool ·
Check whether one chip's output can drive another's input — noise margins and over-voltage across TTL, HC/HCT, LVC, LVCMOS, ESP32, RP2040, STM32, and AVR — pick a level shifter by speed and bus type, design a divider and see its speed limit, and size open-drain pull-ups by rise time.
Tool ·
Pinouts and specifications for 16 popular Microchip PICs from the PIC10F200 to the PIC18F45K22, a configuration-bits generator and decoder (XC8, pic-as, MPASM), timer, PWM, baud-rate, I²C and A/D clock calculators, a PIC16F84A assembler and simulator with LEDs, buttons and a 7-segment display, and an Intel HEX inspector.
Tool ·
Simulate a PID controller on a first- or second-order plant with dead time — step response, overshoot, settling time, a load disturbance, output limits and anti-windup — get gains from Ziegler–Nichols, Cohen–Coon or SIMC tuning rules, copy the controller as C code, and play with a toy glucose loop to see what sensor and actuator delays do.
ElectronicsElectronicsSoftware engineeringBiology and medicine
Tool ·
Chip resistor and capacitor sizes from 01005 to 2512 with power and voltage ratings, the smallest size for a given dissipation, imperial versus metric codes, and a searchable table of diode, transistor, power, SOIC/TSSOP/QFP, QFN/DFN, and BGA packages with body sizes, pitch, and how hard they are to hand-solder.
Tool ·
Steps per mm for belts, lead screws, and gear reductions with microstepping; the resolution you can rely on; the reference voltage for A4988, DRV8825, and TMC2208/2209 drivers; and a corner-speed and step-rate check against your controller.
Tool ·
Convert NTC thermistor resistance and temperature with the Beta model or a Steinhart–Hart fit from three points, design the divider into an ADC with its resolution per degree and self-heating, and convert PT100/PT1000 readings with the Callendar–Van Dusen equation.
Tool ·
Size the base resistor for a BJT switch, work out a MOSFET's conduction and switching losses and junction temperature from its datasheet, check whether 3.3 V or 5 V drive is enough, design a high-side P-channel switch with an NPN driver, and handle inductive loads.
Tool ·
Design Butterworth, Bessel, Chebyshev, and Linkwitz–Riley op-amp filters — low-pass, high-pass, band-pass, and notch — as Sallen–Key or multiple-feedback stages with standard resistor and capacitor values, then check the Bode plot, group delay, step response, tolerance spread, and a SPICE netlist.
Tool ·
Duty-cycle battery life for IoT devices (sleep, radio bursts, sensor reads, hourly and daily events) with regulator quiescent current, temperature derating, and a daily energy budget; battery chemistries, series/parallel pack builder, charge time, and solar panel and battery sizing.
Tool ·
Connect to a Bluetooth Low Energy device from the browser, browse its GATT services, read, write, and subscribe to characteristics with decoders for standard sensors, graph live values, and look up UUIDs.
Tool ·
Interactive pinouts for 36 boards — ESP32, -S2, -S3, -C3, -C5, -C6, -H2 and -P4 (Espressif DevKits, XIAO, Adafruit QT Py and Feather V2, ESP32-CAM, Nano ESP32), ESP8266, Raspberry Pi Pico and Pico 2, Arduino Uno R3/R4, Nano, Mega and Leonardo, Pro Micro, Teensy 4.0, STM32 Blue and Black Pill, and the Raspberry Pi header — with a pin planner, board comparison, and ESPHome/Arduino/MicroPython export.
Tool ·
Truth tables with a column for every sub-expression, push negations inward one named law at a time, brute-force SAT on CNF clauses, Quine–McCluskey minimisation with Karnaugh maps and gate diagrams, equivalence checks, and register bitfields.
Tool ·
Finger-jointed laser/CNC boxes with kerf compensation, dividers, and eight lids — including living, knuckle, side-pivot, and bought hinges with magnet catches — nested onto sheets as SVG or DXF; and 3D-printable enclosures with PCB standoffs, connector cut-outs, and a snap, friction, screw, or hinged lid (print-in-place, snap-fit, filament pin, flexure) as STL — with a 3D preview that opens the lid and flags collisions.
Tool ·
Compute any of 40 standard CRCs (CRC-8 to CRC-64) or define your own, identify an unknown CRC from an expected value, generate C code, and calculate checksums, NMEA, Luhn, and Modbus RTU frames.
Tool ·
Ohm's law and power, series and parallel networks of R, C, and L, voltage dividers with standard-value design, LED resistors, Wheatstone bridges, current dividers, and ADC scaling.
Tool ·
Draw a schematic on a grid and simulate it in the browser — DC operating point with node voltages on the drawing, a transient "oscilloscope" with pulse and sine sources, and AC sweeps with Bode plots — then cross-check it against real ngspice (WebAssembly) or run any SPICE netlist.
Tool ·
Simulate how cells and packs discharge under constant-current, constant-power, resistive, and pulsed loads (Li-ion, LiFePO₄, NiMH, alkaline, coin cells, lead-acid), size supercapacitor hold-up, time bleeder resistors, and analyse measured discharge logs.
Tool ·
Open an ESP32-family .bin — app image, bootloader, partition table, NVS partition, or a full-flash dump — and see its header, segments, app description, checksum and SHA-256 verification, partitions, OTA state, and every NVS key and value.
Tool ·
Paste a Guru Meditation, abort, assert, watchdog, or brownout log from an ESP32, S2, S3, C3, C6, or H2 and get the cause explained, the registers annotated, the backtrace resolved against your ELF, and the reset reason decoded.
Tool ·
Design ESP-IDF and Arduino-ESP32 partition tables visually — add OTA, NVS, SPIFFS, LittleFS, and FAT partitions, check alignment and overlaps, and export the CSV or a flashable partitions.bin.
Tool ·
Build ESPHome device YAML from a board and a catalogue of sensors, switches, lights, and buses — with live output, a secrets.yaml template, and a linter for pin conflicts, strapping and flash pins, ADC2 with Wi-Fi, I²C address clashes, and ESP8266/ESP32 differences.
Tool ·
Open VCD, Saleae, or sigrok captures (or raw bytes) in the browser, zoom and measure the waveforms with cursors, and decode UART, I2C, SPI, and 1-Wire traffic into bytes, text, and a searchable event list.
Tool ·
Connect to an MQTT broker over WebSockets, subscribe with wildcards, watch messages as a live log and topic tree, and publish text, JSON, or binary — for testing IoT devices and Home Assistant setups.
Tool ·
Baud-rate register values with error for AVR, STM32, and ESP32 UARTs; timer prescaler and period solver; ESP32 LEDC PWM resolution; I²C pull-up sizing with an address directory; and SPI clock dividers.
Tool ·
Build and decode Modbus RTU, ASCII, and TCP frames, decode registers in every word order, draw CAN bit streams with stuff bits and CRC-15, calculate MCP2515, ESP32 TWAI, STM32, and SJA1000 bit timing, estimate bus load, and decode DBC signals, candump logs, OBD-II PIDs, and J1939 IDs.
Tool ·
Build a PCB layer stackup (or start from typical 2-, 4-, and 6-layer boards), size microstrip, stripline, differential pair, and coplanar traces for 50, 85, 90, and 100 Ω, check them with a built-in 2-D field solver, and budget delay and skew.
Tool ·
IPC-2221 trace width and current, trace and via resistance, AWG and metric wire tables, cable voltage drop, fuse sizing, and an approximate microstrip impedance.
Tool ·
Draw sprites, tiles, and screens with real hardware palettes — Amiga, C64, NES, Game Boy, ZX Spectrum, Atari 2600, PICO-8, and 1-bit OLEDs — then export C arrays, bitplanes, CHR tiles, sprite data, PNG, or animated GIF.
Tool ·
Build, explain, and lint platformio.ini files — resolve extends, [env] inheritance, and ${…} interpolation per environment, pick boards with real IDs, and get the pio and Arduino CLI commands for each environment.
Tool ·
Size the inductor, capacitors, and currents for buck, boost, and inverting buck-boost converters, check linear regulator heat, and budget power, injection, and wiring for WS2812/NeoPixel LED strips.
Tool ·
Convert dBm, watts, and microvolts; cut antennas for any band; work out free-space path loss, link margin, and Fresnel clearance; calculate LoRa time-on-air and duty cycle; and look up Wi-Fi, BLE, and Zigbee channels.
Tool ·
Read and make resistor colour bands (3 to 6 bands), find the nearest E-series value or the best two-resistor combination, and decode SMD, capacitor, and inductor markings.
Tool ·
Turn raw I2C register bytes from BME280/BMP280, MPU-6050, INA219, ADS1115, SHT3x, DS3231, and DS18B20 into calibrated readings using the datasheet formulas, and build the configuration registers and I2C transactions to set them up.
Tool ·
A Web Serial terminal and live plotter for Arduino, ESP32, ESP8266, and Pico boards, plus an ESP firmware flasher built on esptool-js — all in the browser, no drivers or IDE.
Tool ·
Size a rooftop solar system from your electricity use and location, then see payback, NPV, IRR, the cost per kWh of solar energy, financing, and a year-by-year cash flow over its life.
Tool ·
Junction temperature through θJC, interface, and heatsink; MOSFET, regulator, resistor, and diode losses with temperature feedback; finned heatsink performance in still or moving air; PCB copper as a heatsink; pulsed heating from Foster networks; airflow for enclosures; and chip heat flux with the coolant flow liquid cooling needs.
Tool ·
RC, RL, and LC time constants with charge curves; filter cutoffs with Bode plots; reactance and resonance; 555 timers; op-amp gain and resistor choice; Zener regulators; and linear-regulator heat.
Project ·
A low-latency pub/sub service: back-end services publish state changes, and clients subscribe over WebSocket or long-poll to receive events plus a server-maintained snapshot of each object.
Article ·
A local-first monitor for an off-grid 15 kW solar system that forecasts surplus power from the weather and tells you when to run heavy loads.
Project update ·
How a conversation with Bill Borsari became a walk-through history of the Amiga at the Vintage Computer Festival. It was built almost entirely at my home, some 2,500 people came through, and we finished the day with the Amies.
Project ·
A walk-through history of the Amiga, built for its 40th anniversary at the Vintage Computer Festival at the Computer History Museum, with the Amies awards in the evening.