System Design

Here is the circuit diagram:

Step 1:

  1. Prepare the water pump and the pipe
  2. Pour out the water from the base of the bottle
  3. Make a small hole (diameter ~ 1 cm) on one side of the base of the bottle for the pipe to pass through
  4. Connect the water pipe to the water pump
  5. Put the water pump into the base of the bottle
  6. Take out the wire through the small hole
  7. Attach the pipe with tapes

Step 2:

  1. Prepare the Microbit
  2. Detach the USB cable from the laptop
  3. Connect the microbit to the small AAA battery case

Step 3:

  1. Soil moisture sensor
  2. Put the soil moisture sensor into the soil
  3. Connect the soil moisture sensor to the microbit

Step 4:

  1. Connect the water pump, relay board and microbit
  2. Connect P1 and GND of microbit to the INPUT side of the relay board

The set-up will be like this

Step 5:

  1. Press button A
  2. Press button B
  3. Check the auto watering function one hour later