Fan
A blade on the shaft moves air.
need dc motor · a prop or cut paper blade · battery
do press-fit the prop, power it, aim it.
Salvage one from a toy, a printer, a drone, a dead drive — and put it to work. They're cheap, low-voltage, and surprisingly capable. Here's a field of them, and what to make them do.
The classic 2-wire toy "can." Flip the leads to reverse; chop the supply (PWM) for speed.
2 wiresDrone & RC motors. Efficient and strong, but needs an ESC to spin.
needs ESCFrom printers & disc drives. Moves in exact steps — precise, needs a driver.
moves in steps3 wires. Feed it a PWM pulse and it holds an angle. Robotics, RC steering.
holds an angleTiny pager / coin motors with an offset weight — pure buzz.
hapticsA DC motor with a gearbox bolted on. Trades speed for torque.
torqueA blade on the shaft moves air.
need dc motor · a prop or cut paper blade · battery
do press-fit the prop, power it, aim it.
An offset weight makes it skitter across the table.
need vibration motor · a toothbrush head · coin cell
do stick the motor to the bristles — it walks itself.
A magnet on the shaft drags a stir-bar in the liquid above.
need dc motor · two magnets · a dish
do spin a magnet under a cup; a magnet-bar inside follows.
A collet on the shaft turns it into a rotary tool.
need a higher-rpm dc motor · a chuck/collet · bits
do chuck a bit; drill, sand, polish small work.
eye protectionSpin small tubes fast to separate what's in them.
need a balanced rotor · dc/brushless motor · an enclosure
do load tubes in balanced pairs, shield it, then spin.
⚠ balance & shield — projectile riskTurn the shaft and the motor makes voltage.
need a brushed dc motor · an LED · your fingers
do spin it fast — the LED lights. Add a diode + cap to store it.
Wind spins blades, the motor-generator makes power.
need dc motor · blades · a mast · an LED/charger
do mount blades on the shaft, point it into the breeze.
Flowing water turns the shaft into a trickle of current.
need dc motor · a paddle wheel · a tap or stream
do let water push the paddles; harvest from the leads.
One geared motor per wheel — drive and steer by speed.
need 2 geared motors · wheels · an H-bridge · battery (+ a microcontroller)
do run the motors through the H-bridge; spin them apart to turn.
A geared motor walks a loop of belt past a point.
need geared motor · two rollers · a belt loop
do drive one roller; tension the belt over the other.
Rollers squeeze soft tubing to push liquid along — no contact with the pump.
need geared motor · a roller head · flexible tubing
do rotate the rollers over the tube; meters doses cleanly.
Two steppers drag a pen across X and Y to draw.
need 2 steppers · drivers · a frame · a microcontroller
do count steps per axis; lift the pen with a small servo.
A stepper creeps a camera along a rail for smooth motion shots.
need a stepper · a driver · a rail + belt
do step slowly along the belt; time it to your shot.
A dead optical drive hands you a precise linear sled, free.
need a scrap CD/DVD drive · a stepper/motor driver
do harvest the sled + stepper → a ready micro-positioner.
A servo per joint holds each angle on command.
need hobby servos · brackets · a PWM source
do send each servo a pulse; pulse width = the angle.
A stepper or geared motor ticks the hands at a steady rate.
need a stepper/geared motor · a driver · gearing
do gear the output down to one turn per minute / hour.
Step them at audible rates and they play tunes — the pitch is the step frequency.
need steppers · drivers · code
do map notes to step rates; the coils sing.
The homopolar motor: the simplest motor there is.
need an AA battery · a neodymium magnet · copper wire
do balance a wire loop on the battery touching the magnet — it spins on its own.
A spinning mass torques its frame — enough to balance a stick or cube on an edge.
need a brushless/dc motor · a flywheel · a sensor + controller
do spin the wheel to counter a tip; it stands up.
Hard-drive and brushless motors hide strong neodymium magnets worth keeping.
need a dead HDD or brushless motor
do pry them out for other builds.
⚠ very strong — pinch hazardBonus physics: a magnet falls slowly down a copper tube — the same braking force inside every motor.
need a neodymium magnet · a copper pipe
do drop it in and watch it crawl (Lenz's law).
workbench series · salvage, spin, generate, repeat · most of these run on a battery and a good idea