Engineering
Logic gates, bridge building, gears, and structural analysis
MPC Pendulum Swing-Up (MPPI)
Sampling-based Model Predictive Control: K candidate torque rollouts over horizon H, MPPI cost-weighted update, bounded torque |u|≤u_max — swing up an inverted pendulum live and watch the planner replan.
A* / Dijkstra Pathfinding (Grid)
Interactive 40×28 grid pathfinder: A* (f=g+h), Dijkstra, or greedy best-first; Manhattan / octile / Euclidean heuristics, 4- vs 8-connectivity, paint walls + weighted cells, watch open / closed sets expand.
3-Link 3D Arm Inverse Kinematics (CCD)
Continuation of two-link-arm-ik into 3D: 3 revolute joints (yaw + 2 pitches) solved with constrained Cyclic Coordinate Descent. Drag target in 3D or follow a helix / lemniscate / figure-8 trajectory.
Bicycle Model & Stanley Controller
Kinematic bicycle (rear-axle): δ = θ_e + atan2(k_e·e, v) Stanley path-following law. Pick oval, race-track, lemniscate, sine-road or S-curve and tune k_e, v, L; live cross-track e(t) and steering δ(t).
Stress–Strain & Hooke’s Law
Qualitative σ–ε curve: elastic Hooke region, yield, strain hardening, necking, and fracture. Drag strain and tune E, σ_y, σ_u.
Quadcopter 2D (Pitch)
Side view: two rotors, PD on thrust split vs pitch — whiteboard quad slice.
Watt Governor (schematic)
Flyballs and sleeve vs RPM; steam throttle gap — speed feedback cartoon.
Logic Gate Simulator
AND, OR, NOT, NAND, XOR. Drag, drop, connect, see output.
Truth Table Generator
Build a circuit, auto-generate the truth table.
Bridge Builder
Place beams and joints. Apply load. See stress distribution.
Gear Train
Connect gears, adjust teeth count, see speed and torque ratios.
Planetary Gear Set
Sun, planets, internal ring: Willis equation, hold Sun/ring/carrier and compare speed ratios.
Beam Q, M & N Diagrams
Simply supported beam: point load + UDL; shear, bending moment, and uniform axial diagrams.
AM / FM Modulation
Carrier + message: AM envelope vs FM phase; waveform and DFT spectrum snapshot.
Planar Truss (triangle)
Symmetric 3-bar truss: bar forces and reactions vs span, height, and apex load.
PID Controller (1D)
Cart on a track: Kp, Ki, Kd and random velocity impulses toward set-point x = 0.
Two-Link Arm IK (2R)
Planar 2R manipulator: mouse goal, elbow-up / elbow-down inverse kinematics; joint angles live.
Four-Bar Linkage
Crank–rocker geometry with coupler-curve trace; link lengths and crank speed.
Cam & Follower
Eccentric circular cam and knife-edge follower: lift and estimated velocity.
Finite State Machine
Traffic-light Moore machine: timed green–yellow–red cycle or manual step; state graph.
ADC / DAC (Sampling)
Sine → samples → quantization → ZOH; Nyquist and optional aliasing demo.
Stepper Motor (4-phase)
Full-step vs half-step commutation; rotor snaps as coils A–B–A′–B′ sequence.
Thermostat vs PID
First-order room: on/off hysteresis vs continuous PID heater power.