A little code. A world of possibilities.
Build a virtual robot, connect a few blocks, and watch your ideas move. SpikeSim brings coding, 3D practice and guided lessons into one offline robotics workspace.
The real SpikeSim workspace: editable blocks, a virtual robot and a 3D practice field.
The download website is configured for Vercel connected to GitHub. GitHub
stores the source and Windows release files; Vercel serves website/ using the
root vercel.json. Run npm.cmd run site:dev for the local website and
npm.cmd run site:check for its browser checks. See release setup.
The website keeps downloads disabled until a real release asset is published.
The original SpikeSim identity now includes a route-S mark, consistent app/session branding, desktop icons and reusable SVG/PNG artwork. Review the local brand studio or brand guide. With the preview running, open http://127.0.0.1:5173/brand/index.html.
Learn now offers 17 lessons for secondary-school students, with familiar examples, existing demonstration videos, 51 explained screenshots, predictions and short checks. Students can edit and run a separate lesson experiment without replacing their projects. Topics include Python reading, My Blocks and their inputs, custom gyro turns, yaw and wheel conversions. The interactive angle and wheel tools explain the maths visually. Python remains a read-only view of simulator helper code. See Learn. The lesson library also filters completed lessons and lessons still to finish, with searchable results and completion counts.
Sumo together lets two students compete using blocks on the same Wi-Fi. Build the
app and run npm.cmd run sumo:host for browser hosting, or host from the desktop app.
Share the local invitation link/code. See hosting and limitations.
The redesigned sumo screen has player readiness cards, a round clock, a clearer
host/join setup and an arena-only expanded view with keyboard controls.
The host also serves Learn videos, captions and runnable 3D experiments.
Class competitions supports individual or team entries in sumo and timed 3D
arenas. Teachers can choose starter courses, FLL practice tasks, maze, fire rescue
and bundled FLL/WRO fields, with preparation and run timers. Completed attempts
rank by fastest time. Full competition fields use a published task and teacher
confirmation; timers and rankings remain automatic. Approval, editing handover,
locked submissions, saved results and CSV/program export are included.
After building, run npm.cmd run classroom:host
and open http://127.0.0.1:41866/?competition=host. See the
teacher guide and remaining scope.
Class competitions with demonstration students: prepare, run a match and review the results.
The app opens one student workspace: 66 simple Blockly instructions beside a large Gears-powered 3D simulator. One picker includes 41 learning missions, 32 Gears practice challenges, 38 FLL/WRO fields, and open practice. The simulator has ten robot choices, live sensors, hub lights, sound, camera controls, a resizable split, and an expanded view. There is no separate Gears library screen. Projects retain their blocks, robot ports, selected robot, and world.
Build a robot opens the physical component editor inside SpikeSim. Its FLL practice base has drive motors, front and rear powered attachments, color/distance sensing, and a gyro. Add or position parts, change dimensions, and use the result with your existing blocks. Build a ground edits field images, objects, walls, and mechanisms; it also accepts your own PNG/JPEG/WebP image. Custom designs save inside .rlproj files and remain available when switching back to a preset. The simulator stays covered by SpikeSim's loading screen until the selected world is ready, so the upstream editor no longer flashes during loading.
The FLL collection has eight mats (2018–2025), with two RePLAY 2020 layouts. The copied 2018, 2019 and 2025 fields have no mission models and are labelled Mat only; the 2020–2024 fields include models. These are practice fields, not a claim that every official FLL mission has an implemented score checker.
Run the browser version with npm.cmd run dev:web and open http://127.0.0.1:5173. Drag a Movement block beneath the start block, then click Run program. Examples includes a square, lights and sound, and a distance-sensor loop. F5 or Ctrl+Enter runs in 3D; Escape stops; Ctrl+R resets. The 2D replay also supports pause, stepping, playback speed, and a timeline.
Import program accepts SpikeSim .rlproj and supported SPIKE Prime .llsp3 / Scratch .sb3 word-block projects. Nested archives, block graphs, and ports are validated before replacing a draft. Unsupported Python projects, icon blocks, events, or instructions are reported without changing the open program. This is a conversion, not full SPIKE compatibility: the virtual hub does not run SPIKE firmware, and real routes need calibration.
Our block-generated Python controls Babylon/Ammo physics through a bounded Skulpt adapter inside the embedded simulator. The main desktop renderer keeps its strict CSP; the legacy engine has a separate loopback origin with no Electron preload privileges. The optional deterministic SVG 2D replay uses the existing worker graph interpreter. The Python tab remains a read-only helper-code preview. The two simulators have different physics and timing; they are not synchronized camera views. Learning-mission scoring uses actual observations from the selected simulator. All 41 classroom reference programs have deterministic 2D tests and recorded three-star 3D runs, with projects and results in recordings/index.html. Remaining practice and competition coverage is unfinished, and new mission/video work is paused. Competition fields do not award classroom mission stars.
Gears source, robots, worlds, models, upstream examples, and notices are bundled in public/gears/. The simple toolbox does not yet expose every Gears-specific device (such as camera vision, GPS, or pen drawing), arbitrary Gears XML/Python projects, or multi-robot programming. The builder assembles simulation components rather than individual LEGO bricks. Direct Python editing, permanent XP/unlocks, cloud classroom sync and assignment packs remain unfinished. Local teacher competitions are described above. See the workspace notes for the runtime and port mapping.
npm.cmd run build builds the web app and Electron entry files. Windows installers are distributed through GitHub Releases. Local installation, installed-app acceptance and uninstall passed, including simulator/builders, program files, lesson media, classroom workers and restart recovery. npm.cmd run desktop:check repeats acceptance with isolated data. This is an unsigned Windows preview. See Windows packaging and acceptance for instructions and remaining limits.
Validation: npm.cmd run lint, npm.cmd run typecheck, npm.cmd test -- --maxWorkers=1, npm.cmd run e2e -- --workers=1, and npm.cmd run build. Blockly notices are bundled in public/licenses/. Gears is GPL-3.0; preserve its notices and provide corresponding source for GPL-covered distributions. Upstream FLL artwork redistribution permission remains unverified. The repository includes the full simulator with its upstream licenses and credits. See asset notices.