A knob that dims an LED

Wire it in

Sensors and actuators this board drives, with the real connections.

• Push buttonSupply 3.3 V

  Use pinMode(D5, INPUT_PULLUP); the pin reads LOW while the button is pressed.

  Part pin	Board pin
  leg 1	D5Wire colour white
  leg 2	GNDWire colour black

  Careful

  Not on D3, D4 or D8: a pressed button or an external pull resistor there changes the boot mode. D0 has no pull-up.

  Inspect Push button
• PotentiometerSupply 3.3 V

  Ends to 3V3 and GND, wiper to A0. The top 0.1 V of travel reads 1023 because A0's full scale is 3.2 V.

  Part pin	Board pin
  end 1	3V3Wire colour red
  wiper	A0Wire colour yellow
  end 2	GNDWire colour black

  Inspect Potentiometer
• Light sensor (LDR)Supply 3.3 V

  LDR from 3V3 to A0 and 10 kΩ from A0 to GND: more light gives a higher reading.

  Part pin	Board pin
  LDR leg 1	3V3Wire colour red
  LDR leg 2 + 10 kΩ to GND	A0Wire colour yellow

  Inspect Light sensor (LDR)
• TMP36 temperature sensorSupply 3.3 V

  Runs from 3.3 V (2.7-5.5 V). 0.5 V means 0 °C and each 10 mV is 1 °C: °C = (raw x 3.2 / 1023 - 0.5) x 100.

  Part pin	Board pin
  +Vs	3V3Wire colour red
  Vout	A0Wire colour yellow
  GND	GNDWire colour black

  Inspect TMP36 temperature sensor
• SG90 micro servoSupply 4.65 V

  Servo library, signal on D5. The 3.3 V signal is enough for an SG90.

  Part pin	Board pin
  orange (signal)	D5Wire colour orange
  red (+)	VINWire colour red
  brown (GND)	GNDWire colour brown

  Careful

  Power it from Vin (about 4.65 V on USB), never from 3V3. Its stall current (several hundred mA) drags the supply down and resets the board, so give it its own 5 V supply with a shared GND for real work.

  Inspect SG90 micro servo
• Capacitive soil moisture sensorSupply 3.3 V

  AO to A0, powered from 3V3 so the output never exceeds the 3.2 V range. Power it only while measuring to slow corrosion.

  Part pin	Board pin
  VCC	3V3Wire colour red
  GND	GNDWire colour black
  AO	A0Wire colour yellow

  Inspect Capacitive soil moisture sensor