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Circuits from the Shorts

Every Short has a page here. Type the short address shown under a card, or on the part in the video, and it opens straight away. New Shorts get their page on the day they come out.

  • A 12 V supply, a timer relay module, a solenoid valve on a brass tap filling a 20 litre bottle, and a proximity sensor beside the bottle

    Automatic water filling system

    wirecora.com/water

    Put a bottle under the tap: the sensor sees it, the timer relay closes, the solenoid valve opens and water runs. After the set time the relay lets go, the valve closes and the water stops.

    Parts and how it works
  • An Arduino Uno, a GY-521 MPU6050 board on a handlebar, a 470 ohm resistor and a WS2812B LED strip with the left half lit amber

    Smart bike indicators

    wirecora.com/bike

    Lean the bike to the left and the left half of the LED strip sweeps amber from the middle outwards. Lean right and the right half does. Straighten up and the strip goes dark.

    Parts and how it works
  • An NE555 timer, a TIP120 transistor, a diode, a 5 V supply, a tank with HIGH and LOW probes, and a small pump

    Automatic water tank filler with a 555

    wirecora.com/tank

    Water leaves the LOW probe: the 555 switches the pump on. Water reaches the HIGH probe: the pump stops. In between, the pump keeps doing what it was doing, so the tank fills from LOW to HIGH and then waits.

    Parts and how it works
  • A PAM8403 amplifier module on a 5 V supply, a tone generator on its input, and three speakers: a tweeter with a 2.2 ohm resistor and 2.2 uF capacitor, a midrange with a 1 ohm resistor, 0.2 mH coil and 6.8 uF capacitor, and a woofer with a 1.5 mH coil and a 15 uF capacitor across it

    3-way speaker crossover

    wirecora.com/crossover

    A test tone sweeps from high to low. Sound waves appear on the tweeter first, then on the midrange, then on the woofer, because each speaker gets only the part of the sound its filter lets through.

    Parts and how it works
  • An NE555 timer, two blue 10 k trimmers with a push button each, an 18 k and a 270 k resistor, a 1N4148 diode, a 100 nF capacitor, a 4 x AA battery pack and an MG995 servo with a white horn

    Servo control with a 555 and two buttons

    wirecora.com/servo

    Hold the top button and the servo horn swings one way. Let go and it comes back to its rest position. Hold the lower button and the horn swings the other way, then comes back again when the finger lifts. In the Short the horn swings a full half turn each way; a real MG995 moves about a quarter turn each way with these pulses (see Simplified).

    Parts and how it works
  • A BC547B transistor with its legs down, an 18 k resistor, a 1 k resistor and a 22 uF capacitor beside it, a 3.5 mm AUX plug at the top right with its tip up, an 18650 cell on the left and a big 8 ohm speaker at the bottom right

    Simple audio amplifier with a BC547B

    wirecora.com/amp

    Music from a phone goes in at the AUX plug, one transistor and one cell drive the speaker, and the speaker plays the music quietly. In the video the cone pumps with the beat; a real small cone barely moves.

    Parts and how it works
  • A 3.7 V 18650 cell, three LEDs (green, yellow, red) and a buzzer, each on its own BC547 transistor, and five probe wires running into a cut-away water tank

    Water level indicator with a buzzer

    wirecora.com/level

    Water pours into the tank. As the level climbs, the red LED lights first, then the yellow, then the green. When the water reaches the top probe the buzzer sounds: the tank is full.

    Parts and how it works
  • An LM3914 chip, a bar of ten red LEDs, an IR LED and an IR phototransistor side by side, a 10 k pot, a 330 ohm and a 2.2 k resistor, and a 9 V battery

    Hand distance sensor with a 10-LED bar

    wirecora.com/bar

    Hold your hand over the two small sensors: the closer it gets, the more of the ten red LEDs light up, from the bottom of the bar to the top. Pull the hand away and the bar goes dark again.

    Parts and how it works
  • A TP4056 charger module fed by a 5 V phone charger, a red Charging LED and a green Full LED each with a 1 k resistor, and a green 18650 cell in a holder with a percent counter

    18650 charger with a full indicator

    wirecora.com/charger

    The charger is plugged in and the holder is empty, so the green Full LED is already lit. Drop an 18650 cell into the holder and the green LED goes out, the red Charging LED comes on and a counter climbs. When the cell is full the red LED goes out and the green Full LED lights again. Lift the cell out and the green LED stays on.

    Parts and how it works
  • Two motorcycle turn-signal lamps, a 2 way toggle switch, an NE555 with two 10k resistors and a 22 uF capacitor, an IRFZ44N and a 12 V motorcycle battery

    12 V bike indicator flasher with a 555

    wirecora.com/flasher

    Hold the toggle to the left and the left lamp flashes amber about twice a second for as long as you hold it (three flashes in the clip). Hold it to the right and the right lamp flashes. Let go and the lever springs back to the middle, so both lamps stay dark.

    Parts and how it works
  • A 12 V supply, a 5 V supply, a 5 V relay module and an IR sensor clamped to a tap over a white basin, with a 12 V solenoid valve under the basin, a stop valve and a blue water hose

    Automatic water tap

    wirecora.com/faucet

    Hold your hands under the tap: the IR sensor sees them, the relay clicks and water pours onto your hands. Take your hands away and the relay clicks off and the water stops.

    Parts and how it works
  • Three red LEDs at the top left and three blue LEDs at the top right, each with a 330 ohm resistor, an NE555 timer in the middle with a 1 k and a 33 k resistor, a 10 uF capacitor and a 10 nF capacitor, a rocker switch and a 9 V battery at the bottom

    Police lights with a 555

    wirecora.com/police

    A finger presses the rocker switch on. The three red LEDs light first, then the red and the blue LEDs take turns, about four swaps a second, like the lights on a police car. Press the switch off and everything goes dark.

    Parts and how it works
  • A CS209A chip with a blue 20 k trimmer beside it, two orange 2.2 nF disc capacitors, a copper search coil with a kitchen knife lying across it, a red LED with a 1 k resistor and a buzzer at the top, a 9 V battery and a handheld detector wand

    Metal detector with a CS209A

    wirecora.com/metal

    Slide a kitchen knife onto the search coil and the red LED lights and the buzzer sounds. Take the knife away and both stop. Then a key goes onto the coil and the LED and buzzer come on again.

    Parts and how it works
  • A BC557 transistor seated in a three-way terminal block marked C, B and E, a red marker pressing the TEST button, a lit green LED with LED ON = OK above it, two 1 k resistors and a 3.7 V cell

    PNP transistor checker with an LED

    wirecora.com/pnp

    Plug a BC557 into the C, B and E terminals and press TEST: if the transistor works, the green LED lights. Let go and the LED goes out. Pull the transistor out and nothing lights, even with TEST pressed.

    Parts and how it works
  • A white box printed wirecora.com with a clear side window: inside, an SG90 micro servo, a 100 uF capacitor and an Arduino Nano; on top, a mini toggle switch and an open lid with a white plastic arm reaching for the lever; a 5 V 2 A supply below the box and a hand with a red marker at the top right

    Arduino useless box

    wirecora.com/useless

    Flip the switch ON and the box pushes its lid open, reaches out with a plastic arm and flips the switch straight back OFF, then hides again. The second time it is angry: the arm comes out at full speed, the lid slams, and a moment later the lid peeks up once.

    Parts and how it works
  • A night desk with a black 12 V LED desk lamp lit warm over a circuit: a 12 V 2 A adapter, two BC547 transistors, an NE555P, a clear 12 V relay marked COM and NO, a 1N4148 and a 1N4007 diode, resistors labelled 10k, 1M, 10k, 100k, 100k, 1M and 47k, a 10 uF memory capacitor, a microphone at the bottom left and two open hands about to clap

    Clap switch lamp with a 555

    wirecora.com/clap

    Clap once and the desk lamp turns on. Clap again and it turns off. A sound that comes less than about half a second after a clap is ignored, so the clap's own echo and the relay's click do not switch it back.

    Parts and how it works
  • A cut-away house wall with a cat door: an orange cat with a magnet tag on its collar walks through the tunnel under the flap, which an MG995 servo in the white wirecora.com housing has lifted. A reed switch sits in the sill, and below the floor are an Arduino Nano, a red and a green LED with 220 ohm resistors, a 1000 uF capacitor and a 5 V 2 A supply

    Smart cat door with a magnet tag

    wirecora.com/catdoor

    The cat walks up to the door. The magnet tag on its collar passes a reed switch in the sill, the green LED lights and a servo swings the flap up. Two seconds after the tag has gone the flap closes slowly and the red LED lights. A raccoon with no tag pushes its nose on the flap, and the flap stays locked.

    Parts and how it works
  • A peace lily in a terracotta pot on a windowsill with a capacitive soil sensor in the soil, a clear wirecora.com water reservoir with a pump inside and a hose to the pot, and below the sill an Arduino Nano, a TIP120 with 1 k and 10 k resistors, a 1N4007 diode, a 5 V supply and an OLED screen reading OK 53% PUMP ON

    Self-watering plant with a soil sensor

    wirecora.com/plant

    When the soil dries out, the screen reads DRY, a small pump in the water reservoir starts and water runs through a clear hose into the pot. The number on the screen climbs as the soil gets wet, the drooping leaves lift, and at 70 % the pump stops until the soil is dry again.

    Parts and how it works
  • A 16x2 LCD reading WARNING! Object at 15 cm above a radar fan, a hand setting a wooden block in front of an HC-SR04 sensor on an SG90 servo in a round wirecora.com base, an Arduino Nano, a 1 k resistor, a BC547 and a buzzer, and a 5 V supply

    Arduino radar guard with an HC-SR04 and a servo

    wirecora.com/radar

    An ultrasonic sensor on a servo sweeps from side to side. Put something within 30 cm in front of it: the sweep stops on it, the LCD says WARNING! Object at 15 cm and the buzzer beeps three times. Move the object and the sensor follows it in 5 degree steps. Take it away and the screen says Area is Empty and the sweep starts again.

    Parts and how it works
  • A stainless kitchen bin with wirecora.com on its side and its lid swung up by an MG995 servo on the hinge, a hand holding a crushed can 9 cm in front of an HC-SR04 sensor, an Arduino Nano, a 1000 uF capacitor and a 5 V 2 A supply

    Touchless trash can with an Arduino and an HC-SR04

    wirecora.com/trash

    Bring a hand with rubbish within 20 cm of the sensor and the lid swings up by itself. Drop the rubbish in and take your hand away: one second later the lid closes, slower than it opened.

    Parts and how it works
  • A navy-blue model front door opening in a grey clapboard wall with a green MATCH sign on it and a finger pushing its top corner, a round R503 fingerprint sensor with a blue ring on the wall, a lock solenoid printed wirecora.com with a 1N4007 diode at its leads, and below a 12 V 2 A adapter, an LM2596 module, a relay module, an Arduino Nano, a BC547, a buzzer and 1k, 1.8k and 3.3k resistors

    Fingerprint door lock with an Arduino and an R503

    wirecora.com/lock

    Touch the sensor's ring with an enrolled finger: about half a second later the ring turns blue, the relay clicks and the solenoid pulls its bolt back, so the little door swings open with a push. After 2.2 s the bolt springs out again. A finger the sensor does not know gets two red flashes on the ring and one short buzz, and the bolt stays in.

    Parts and how it works
  • A teal model patio umbrella standing open in a concrete base printed wirecora.com, an LDR on top of its pole, an MG995 servo on the pole pushing the runner up, a bistro chair and a glass of lemonade under a bright sun, and below an Arduino Nano, a 1k resistor, a 1000 uF capacitor, a yellow SUN LED with 220 ohm, a 5 V 2 A USB adapter and a readout showing A0 884 SUN

    Sun-sensing patio umbrella with an Arduino, an LDR and a servo

    wirecora.com/shade

    A cloud slides off the sun: the light sensor on top of the pole sees it, the yellow SUN LED lights and a servo pushes the umbrella's runner up the pole, so the canopy opens and shades the chair. When a cloud covers the sun and the sky stays dark, the umbrella folds again, slower than it opened.

    Parts and how it works
  • A delivery driver carrying a parcel along a porch at dusk towards a white front door, an HC-SR04 sensor beside the door reading 59 cm, a lit wall lantern, and below it a dark board with wirecora.com printed on it holding an Arduino Nano, a PN2222A, a 1N4148, an 8 ohm speaker sending out sound arcs, a 100 uF capacitor and a 5 V 2 A adapter

    Hands-free porch doorbell with an Arduino and an HC-SR04

    wirecora.com/bell

    Walk up to the door with your hands full and you do not have to press anything. When you come within 60 cm of the sensor, the porch light comes on and the chime plays ding-dong, once. Stand there as long as you like: it does not ring again. When you leave, the light stays on for a moment, then fades out. After 3 s with nobody near, it is ready for the next visitor.

    Parts and how it works
  • A 0.96 inch OLED screen printed Wirecora showing two angry cyan pixel eyes and 7 cm, an Arduino Nano, an HC-SR04 ultrasonic sensor with a flat hand just under it, a 5 V 2 A supply and the word ANGRY

    Robot eyes that react to your hand, with an Arduino, an OLED and an HC-SR04

    wirecora.com/eyes

    A pair of robot eyes on a small screen watches your hand. Far away, the eyes look happy. Closer than 40 cm they turn worried, and closer than 15 cm they turn angry and shake. Take the hand away and they calm down again, back to happy. The distance in cm shows under the eyes.

    Parts and how it works
  • A brown work boot pressing a black foot pedal, a clear blue relay printed 5VDC and Wirecora, a lit green RUN LED with a 1k resistor, two 1N4007 diodes, a 5 V supply and a 12 V 2 A supply, and a big blue motor with Wirecora 12V DC on its nameplate and a flywheel on its shaft

    Foot pedal motor switch with a 5 V relay and a 12 V motor

    wirecora.com/pedal

    Step on the pedal and the 12 V motor runs and the green RUN lamp lights. Lift your foot and the motor coasts to a stop, and the lamp fades out as it slows. The pedal never carries the motor's current: it only switches the relay's coil, and the relay switches the motor.

    Parts and how it works
  • A hand with the red Wirecora marker pressing a push button, a 12 V 5 W bulb glowing at the top right, a countdown ring reading 5.0 s, an NE555P timer and a TIP120 transistor printed Wirecora, 10k, 47k and 1k resistors, a 100 uF capacitor, a 104 ceramic capacitor and a 12 V DC supply board

    Delay OFF timer with a 555

    wirecora.com/delay

    Press the button once: the 12 V lamp lights straight away, stays on for about 5 seconds and then switches itself off. Letting go of the button early changes nothing, and pressing it again while the lamp is on does not restart the time.

    Parts and how it works
  • A traffic light on a pole with its red lamp lit and a grey control box printed Wirecora, four wires from its GND, R, Y and G terminals to an Arduino Nano, a 5 V 2 A supply, the labels 14 mA per pin, limit 20 mA and 220 ohm inside, and below a road seen from above where a red car waits at the stop line and a blue car brakes behind it

    Traffic light with an Arduino Nano

    wirecora.com/traffic

    An Arduino Nano runs a small traffic light: green, then yellow, then red, then green again. On the road below, toy cars drive through on green, brake on yellow and queue at the stop line on red. When the light turns green they pull away one after another.

    Parts and how it works
  • A washing line with socks, a towel and a red T-shirt under a red-and-white striped cover that an SG90 servo has swung flat over them while rain falls from a grey cloud, a rain sensor plate and its blue LM393 board with the wet LED lit on a post at the right, a white laundry basket printed Wirecora, and below an Arduino Nano and a 5 V 2 A supply

    Automatic rain cover for the washing with an Arduino and a rain sensor

    wirecora.com/rain

    Rain starts to fall on the sensor plate and, within half a second, a servo swings a cover down flat over the clothes on the line. The rain lands on the cover, not on the washing. When the plate has stayed dry for a while, the cover lifts back up.

    Parts and how it works
  • A green 3.7 V cell in a holder at the top, a black active buzzer sending out sound arcs, a BC547 transistor, a green LED flaring, fed through a 330 ohm resistor, a 220 ohm base resistor, and the red and black test probes touching the leads of a 1N4007 diode that a hand holds in tweezers, its band towards the black probe

    Continuity and diode tester with a BC547 and a buzzer

    wirecora.com/beep

    Touch the two probes to a wire, a good fuse, or a diode with its band towards the black probe: the buzzer beeps and the green LED lights. A blown fuse stays silent, and so does a diode the wrong way round. That is how you find which end of a diode is which: it beeps one way only.

    Parts and how it works
  • A clear blue relay printed 5VDC and Wirecora with its coil glowing, a green START button and a red STOP (NC) button lying on their sides, a 130 motor spinning a yellow propeller, two 1N4007 diodes and a 1N5819, a 5 V 2 A supply with the label max 0.5 A beside it, wires with moving current dots, the words Stays ON, and a hand with a red marker on its way to STOP

    Start/stop latch with one 5 V relay

    wirecora.com/latch

    Press the green START button once and let go: the relay clicks in and the motor keeps spinning its propeller. Press the red STOP button: the relay drops out and the propeller coasts to a stop. Let go of STOP and nothing starts again until you press START. Machine motor starters use the same start/stop latch; this one runs on a safe 5 V.

    Parts and how it works
  • A small solar panel on an SG90 servo, tilted towards a sun at the top right, on a white stand printed Wirecora, two LDRs at the top left and right (the right one lit warm, the left one dull), two 330 ohm resistors, an Arduino Nano and a 5 V 2 A supply under a yellow Smart Solar Tracker title

    Arduino solar tracker with two LDRs and a servo

    wirecora.com/tracker

    As the sun crosses the sky, two light sensors tell an Arduino which side is brighter, and a servo turns a small solar panel to face the sun, a few degrees at a time. At sunset it goes back to the middle, ready to swing towards the next sunrise.

    Parts and how it works
  • A small solar panel printed Wirecora under a bright sun, wired to a blue TP4056 charger board labelled 7.2 V of 8 V max, an 18650 cell in a holder with a level bar, a 5 V boost board with a USB socket, and a USB cable into a phone whose screen shows 50 % Charging

    Solar power bank with a TP4056 and an 18650 cell

    wirecora.com/solar

    The sun shines on a small solar panel and slowly fills one 18650 lithium cell. Push the USB plug into the phone and the screen lights up: the cell, lifted to 5 V by a boost board, charges the phone. Pull the plug and the panel goes back to filling the cell. It is a top-up: one cell gives about a third of a phone charge.

    Parts and how it works
  • A white dome security camera printed Wirecora with its lens turned up and to the right, a tilt servo and a pan servo on either side of it, an Arduino Nano below, a KY-023 joystick under a finger, and a 5 V 2 A supply labelled 1.3 A of 2 A

    Joystick pan-and-tilt camera with an Arduino and two SG90 servos

    wirecora.com/camera

    Push the thumb stick and the camera's lens follows it: left, right, up and down. Let go and the stick springs back to the middle, and the camera looks straight ahead again. Two small servos turn the camera: one turns it left and right (pan), the other tips it up and down (tilt).

    Parts and how it works
  • A white honey bucket printed wirecora.com on a steel shelf, its stainless honey gate held open by an MG995 servo through a wire pushrod, a thick golden stream falling into a large glass jar about a third full on a scale platform with a bar load cell under it, an OLED on the shelf reading 236 g FILLING with target 500 g, the labels closes 5 g early, Gate 2.5 of 8.5 kg·cm and Opens, a roller chute on the right, and below the table an HX711, an Arduino Nano, a 1000 uF capacitor, an LM2596 and a DC jack, all wired and labelled

    Arduino honey jar filler with an HX711 scale and an MG995 servo

    wirecora.com/honey

    Set an empty jar on the scale and the honey gate opens by itself. A load cell weighs the jar while the honey runs in. The gate shuts about 5 g before 500 g, because the reading lags a little and the gate needs 0.2 s to close, so the jar ends within a few grams of 500 g (about 1 lb). Take the full jar off, set down the next empty one, and it starts again. It stops by weight, not by time: thick cold honey runs slower, but the scale still shuts the gate at the same weight.

    Parts and how it works
  • A night porch table with an orange candy bowl printed wirecora.com and a lit jack-o'-lantern, a bone-white skeleton hand on an MG995 servo slammed down across the candy, a child's hand pulling back out of a red IR beam above an FC-51 sensor on the bowl's rim, two candies in the air, and below the table an Arduino Nano, an LM2596, a 1000 uF capacitor, a barrel jack and a 12 V adapter, all wired and labelled

    Grabbing candy bowl with an Arduino, an IR sensor and an MG995 servo

    wirecora.com/grab

    Reach into the candy bowl and a skeleton hand swings down beside your fingers. It taps twice over the candy, then folds slowly back up and waits. It stops about 1 cm above the candy, next to the reaching hand, never on it. Pull the plug and it is just a candy bowl again.

    Parts and how it works
  • A night porch with a black cauldron printed wirecora.com full of fun-size candy bars on a scale platform over a 5 kg load cell, a skeleton arm on an MG995 servo holding up an ONLY ONE! sign over the bowl, a child's hand in a striped sleeve holding six bars above the bowl, a jack-o'-lantern and a red WS2812B light bar on the step; below, an HX711, an OLED mounted upside down reading ONLY ONE! 6 taken, an Arduino Nano, a 330 ohm resistor, a 1000 uF capacitor between a red and a black rail, an LM2596 set to 5.0 V, a DC jack and a 12 V 2 A adapter, all wired and labelled

    Take-one candy bowl with an Arduino, a load cell and an MG995 servo

    wirecora.com/candy

    The bowl weighs its own candy. Take one bar and nothing happens. Grab a fistful and the light bar under the bowl flashes red, the screen says ONLY ONE! and a skeleton arm throws up a sign. Put the extras back: the count on the screen drops with every bar, and at one bar the light turns green, the screen says THANK YOU and the arm folds down. A second later the bowl counts again from its new weight.

    Parts and how it works
  • A US front porch at night with a red door, a lit window and a jack-o'-lantern: a hooded reaper with glowing red eyes lunges forward on a crank and lever driven by a 12 V worm gear motor, with the 1N4007 flyback diode on the motor's terminals and the 1k eye resistor on the porch floor beside it, a roller home switch and a STEP HERE mat nearby, and below the porch an orange wirecora.com board with an NE555 turned on its side, an IRFZ44N, 10k and 22k resistors, 100 uF, 1000 uF and 104 capacitors, a red +12 V rail along the top and a black ground rail along the bottom, a barrel jack and a 12 V 2 A adapter, all wired and labelled

    Step-pad porch reaper with a 555 timer and a worm gear motor

    wirecora.com/reaper

    Step on the STEP HERE mat and the hooded reaper by the door lunges at you twice with glowing red eyes, then leans back and waits for the next visitor. A 555 timer and a gear motor do it all: there is no code and no microcontroller.

    Parts and how it works
  • A night house wall with slate-blue siding and two paper bats: a child's index finger in an orange-and-black striped sleeve presses a brass doorbell, and a black rubber spider has dropped on an elastic line onto the fingertip from a spool on a yellow TT gear motor, mounted on a charcoal bracket printed wirecora.com with a reed switch under it; on the left an L298N driver, an Arduino Nano, a barrel jack and a 12 V 2 A adapter, all wired and labelled

    Doorbell spider drop with an Arduino Nano, an L298N and a TT gear motor

    wirecora.com/spider

    Press the doorbell and a big rubber spider drops 10 cm onto the finger that rang it, bobs on its elastic line, then climbs back up in three tugs and parks at exactly the same spot, ready for the next trick-or-treater. It drops once per press and only for whoever rings, not for every passer-by.

    Parts and how it works
  • A US front yard at dusk with a porch, an autumn oak, two tombstones and a jack-o'-lantern: a white cloth ghost flies along a fishing-line loop between two flat bicycle wheels, one under the porch roof driven by a 12 V gear motor and one hanging in the tree, while a child in an orange pumpkin hoodie crouches on the path below; a PIR motion sensor on a garden stake and a reed switch at the porch end of the line, and below the yard a black wirecora.com plate with an Arduino Nano, a TIP120, a 1N4007, 1k and 10k resistors, a 1000 uF capacitor, a barrel jack and a 12 V 2 A adapter, all wired and labelled

    Flying yard ghost with a motion sensor, an Arduino Nano and a 12 V gear motor

    wirecora.com/ghost

    A trick-or-treater walks up the path, a motion sensor sees them, and a white cloth ghost launches from beside the porch, swoops across the yard right over their head, flies one lap of a fishing-line loop and parks itself back in its hiding spot, ready for the next visitor. One lap per visitor, and it always stops in the same place.

    Parts and how it works
  • The front of a silver sedan in the rain with one big wiper blade sweeping up across the windshield and a status panel reading light rain - slow, A0 731. A rain sensor plate sits in the lower right corner of the glass, wired to a blue LM393 board. Below are an MG995 servo, a 1000 uF capacitor, an LM2596 buck module, a 1N5819 diode, a 2 A fuse, a black 12 V battery printed wirecora.com, an Arduino Nano, a 220 ohm resistor and a lit blue WET LED

    Automatic rain wiper with an Arduino, a rain sensor and a servo

    wirecora.com/wiper

    The first drops land on a small rain plate on the glass and the wiper starts by itself. When the rain gets heavy it wipes faster with no pause. When the rain eases it slows down again, and once the plate is dry the blade goes back to rest along the bottom of the glass.

    Parts and how it works
  • A US front porch at night under a full moon, with a railing and bare trees: a legless zombie on a wheeled sled has lunged forward on an aluminium rail and slaps its claw on the boards while a trick-or-treater in a white bedsheet ghost costume runs off. A plywood stand holds a 12 V worm gear motor printed wirecora.com with a crank disc and two push rods, a reed switch above the disc, a 1N4007 flyback diode on the motor wires and an HC-SR501 PIR sensor on the porch post. Above the porch a cream board with two BC547 transistors, an IRFZ44N, 4k7, 10k and 22k resistors, a 2 A fuse, a barrel jack and a 12 V adapter, all wired and labelled

    Crawling porch zombie with a PIR sensor, two BC547s, an IRFZ44N and a worm gear motor

    wirecora.com/zombie

    A trick-or-treater walks onto the porch and the legless zombie by the railing lunges at their feet, claw first, slides back and lunges again, then parks in exactly the same spot for the next visitor. A motion sensor, two transistors and a MOSFET run it: there is no code and no microcontroller.

    Parts and how it works
  • A home-office desk in the evening: a white spring-arm desk lamp lit over the desk, a small white desk fan spinning and a warm LED strip glowing under an oak wall shelf. Below the desk a charcoal plate printed wirecora.com holds an ESP32 board, an LM2596 converter, a ULN2003 chip, a blue relay module labelled lamp, a 1N4007 diode by the fan, a barrel jack and a 12 V 2 A adapter, all wired. On the right a phone in a white stand shows the Wirecora Home page with yellow Lamp, Fan and Lights buttons and a grey All off button, and a thumb comes in to tap it

    Phone-controlled smart desk with an ESP32, a ULN2003 and a relay

    wirecora.com/phone

    Tap Lamp on your phone and the desk lamp comes on with a relay click. Tap Fan and the desk fan spins up, tap Lights and the LED strip under the shelf glows, tap All off and the whole desk goes dark. The page on the phone is served by the ESP32 itself on your home Wi-Fi: no app, no cloud, no account, and it keeps working when the internet is down.

    Parts and how it works
  • A floating oak stair at night: a child in light-blue pyjamas holding a teddy climbs it while a warm WS2812B LED strip glows under every tread. An HC-SR04 sensor sits on the wall at the bottom step and another at the top step; above them a white wirecora.com plate holds an Arduino Nano, a 330 ohm resistor and a 1000 uF capacitor, with a 5 V 2 A supply on the wall beside it

    Stair lights that follow you, with an Arduino and two HC-SR04 sensors

    wirecora.com/steps

    Walk up to the bottom step and the stair lights up one step after another, ahead of you, all the way to the top. Leave at the top and the steps fade out behind you in the same order, a little slower. Coming down from the top works the same way in reverse.

    Parts and how it works
  • A small grey steel desk safe with a wirecora.com nameplate, its door swung open on a gold watch and a stack of cash, a 3x4 keypad on its right panel and a green OPEN sign; a reed switch on the door frame, an MG995 servo under the hinge, and below an Arduino Nano with seven keypad wires dropping straight onto its pins, an LCD reading OPEN, a BC547, a 1k resistor, a buzzer and 5 V and 12 V supply modules

    Keypad code door with an Arduino, an MG995 servo and a reed switch

    wirecora.com/safe

    Type a wrong four-digit code and the screen says WRONG CODE, the buzzer buzzes and the backlight blinks. Type 4-7-8-9 and the screen says OPEN, a servo under the hinge swings the little door 75 degrees open, and 1.2 s later it closes it again slowly. A reed switch on the frame tells the Arduino the door is really shut, and the screen says CLOSED. Three wrong codes in a row lock the keypad for 30 s. It is a code door, not a lock: see below.

    Parts and how it works
  • A US front porch at dusk with a lit door, a wall lantern and a jack-o'-lantern: a big black bat with glowing red eyes hangs under the porch roof with its wings spread wide, beaten by a crank on a yellow TT gear motor that sits on a black plate printed wirecora.com beside a roller home switch, while a girl in a witch costume with a pumpkin bucket walks up; a PIR motion sensor on the left post with a 3.3 V tag on its yellow output wire, and below the porch a cream board with a TIP120, a 2.2k resistor, a 1N4007 flyback diode, 100 nF and 100 uF capacitors, a 120 ohm eye resistor and a 4 x AA holder, all wired and labelled

    Flapping porch bat with a motion sensor, a TIP120 and a TT gear motor

    wirecora.com/bat

    Trick-or-treaters walk up to the door, a motion sensor sees them, and the big bat under the porch roof lights its red eyes and beats its wings, about two a second. A few seconds later it folds its wings neatly and waits for the next group. There is no Arduino and no code: the sensor's own timer, one transistor and a switch on the crank do it all, on four AA cells.

    Parts and how it works
  • A 1:10 model garage front with its white roller door rolled up under a roller box printed wirecora.com and a blue hatchback driving in; a limit switch at the top of the doorway, an IR sensor and a second limit switch low on the left, an HC-SR04 on the right showing 26 cm and a yellow TT gear motor top right; below, an Arduino Nano on a half breadboard with 5 V and ground rails, a red L298N motor driver and a 12 V adapter plugged into a barrel jack, every wire labelled

    Model garage door that opens for a car, with an Arduino Nano, an HC-SR04 and an L298N

    wirecora.com/garage

    A car rolls up the driveway. When it is closer than 150 cm the roller door opens by itself and stops at the top. The car drives in past an IR sensor in the doorway, and 0.6 s after it has passed, the door rolls down and stops on the floor. If anything is in the doorway while it closes, it opens again. It is a 1:10 model on 12 V, not a real garage door.

    Parts and how it works
  • A big red and cream striped jack-in-the-box printed wirecora.com on a dark porch beside a wall lantern, its lid swung up and a clown sprung out on a black scissor lift, while a hand holds a jack-o'-lantern candy pail out to it; a yellow TT gear motor with the crank on the box's left side, an HC-SR04 sensor on the right, and below the porch a 1N4007 flyback diode across the motor leads, a 1000 uF capacitor at the MG995 servo plug, a TIP120 with a 1k resistor, a 5 V 2 A USB supply and an Arduino Nano, all wired and labelled

    Porch jack-in-the-box with an Arduino Nano, an HC-SR04, an MG995 servo and a TT gear motor

    wirecora.com/jack

    Hold your trick-or-treat pail out to the box. When it comes within 20 cm, the crank on the side turns once, the lid flies open and a clown springs up about 24 cm, bobbing on its spring neck. About 3 seconds later it folds back in slowly, the lid drops shut on top of it, and once nothing has been near for a second it waits for the next kid.

    Parts and how it works
  • A push button, a resistor and a lit red LED on a 5 volt supply

    Your first circuit, step by step

    wirecora.com/build

    A button, a resistor and an LED. You join four wires; the board shows every step.

    Build this one
  • An infrared sensor, a relay module and a 12 volt solenoid valve, wired

    Touchless tap

    wirecora.com/tap

    Hand near the sensor: the relay clicks and the valve opens. Hands away, water stops.

    Build this one
  • A light sensor, a BC547 transistor and a red LED, wired

    Night light

    wirecora.com/night

    Cover the light sensor and the transistor switches the LED on.

    Build this one
  • A 9 volt battery, a resistor and a lit red LED

    LED with a resistor

    wirecora.com/led

    The simplest circuit that works: a 9 V battery, a resistor and an LED.

    Build this one

Saw a Short whose circuit is not here yet? It is coming. Meanwhile build it yourself from the parts.