pxt-calliope/docs/projects/plant-watering/code.md

# Code

Let's add code so that when the soil moisture level is low, the servo waters the plant.

From the **[soil moisture](/projects/soil-moisture)** project, we know that the moisture is low when the ``reading`` is roughly less than ``500``. We can use this number to add an ``if reading < 500`` in the code to decect a dry condition.

```block
let reading = 0
if (reading < 500) { }
```

The servo is connected to pin **P2** so we can use the ``||pins:servo write||`` block to change the angle of the servo. We want the angle to change to ``0``, wait until the water pours off, and then move the angle back to ``80``.

```block
let reading = 0
if (reading < 500) {
    basic.showIcon(IconNames.Umbrella)
    pins.servoWritePin(AnalogPin.P2, 0);
    basic.pause(3000)
    pins.servoWritePin(AnalogPin.P2, 80)
    basic.pause(3000)
    pins.analogWritePin(AnalogPin.P2, 0)
}
```

Insert the code above in the ``||basic:forever||`` loop of the [soil moisture](/projects/soil-moisture/connect) code.

```blocks
radio.setTransmitSerialNumber(true)
radio.setGroup(4)
led.setBrightness(64)
let reading = 0
basic.forever(() => {
    pins.analogWritePin(AnalogPin.P1, 1023)
    reading = pins.analogReadPin(AnalogPin.P0)
    radio.sendNumber(reading / 4);
    pins.analogWritePin(AnalogPin.P1, 0)
    led.plotBarGraph(
        reading,
        1023
    )
    if (input.buttonIsPressed(Button.A)) {
        basic.showNumber(reading)
    }
    if (reading < 500) {
        basic.showIcon(IconNames.Umbrella)
        pins.servoWritePin(AnalogPin.P2, 0);
        basic.pause(3000)
        pins.servoWritePin(AnalogPin.P2, 80)
        basic.pause(3000)
        pins.analogWritePin(AnalogPin.P2, 0)
    }
    basic.pause(5000);
})
```

Here's a video showing the @boardname@ watering a plant.

https://youtu.be/7eC_VjH1eP0

```package
radio
```