Sensors
Circuits that notice light, touch, sound, heat or water and react to it.
10 builds
VideoThe whole weather station is three parts
A XIAO ESP32C3 reads a temperature and humidity sensor and shows the reading as a colour on an RGB LED.
9 parts · 14 wires
Sensors
VideoHow your ESP32 reads a 12V battery: the voltage divider
Two resistors scale a 12V battery down to a voltage an ESP32's 3.3V input can read safely, with a zener as a backstop.
6 parts · 9 wires
PowerSensors
VideoThe Clapper, recreated: lights that turn on when you clap
Clap once and an LED turns on, clap again and it turns off. A microphone, two transistors and one flip-flop chip.
14 parts · 24 wires
SensorsLights
VideoA laser tripwire alarm, like in the movies
Break the laser beam and a red LED and buzzer latch on until you press reset. A photoresistor and one 555 timer.
14 parts · 22 wires
SensorsGames and toys
VideoIt tells me how full the tank is
Three LEDs stacked like the tank they watch: each one lights when the water reaches its probe. Three transistors, no chip.
14 parts · 13 wires
Sensors
Premieres Oct 8A lie detector from two transistors
A skin resistance meter: a green LED fades and a red one comes up as your fingers sweat. It reads sweat, not lies.
12 parts · 15 wires
SensorsGames and toys
Premieres Oct 11A lamp you turn on by touching it
Tap a metal pad and two white LEDs turn on, tap again and they turn off. One flip-flop chip and a MOSFET.
13 parts · 13 wires
LightsSensors
Premieres Oct 13This LED turns red when the room gets hot
An RGB LED that shows the room temperature: red when it's hot, blue when it's cold, green in between. Two knobs set the limits.
13 parts · 23 wires
SensorsLights
Premieres Oct 26How does a night light know it's dark?
A night light that switches two LEDs on when the room goes dark. A photoresistor, a trim knob and two transistors.
11 parts · 8 wires
SensorsLights
Premieres Oct 31How bright is it in here, in four LEDs
Four LEDs that light one after another as a room gets brighter. A photoresistor and one quad op amp chip, no code.
18 parts · 21 wires
SensorsTools and test
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