school holiday project - pot plant meter

This is a little school holiday project we did today. A little "plant clock" for Snappy, our venus fly trap.

plant clock

Parts:
  • Arduino uno
  • little servo
  • soil meter
  • cardboard
  • sellotape

We created the clock face by drawing around a dinner plate, onto a cardboard box. The arrow is from some lighter cardboard packaging.

Code:
#include <Servo.h>

const int led_pin = 11;
const int soil_pin = A5;
const int servo_pin = 9;

const int dry = 0;
const int waterme = 45;
const int ok = 90;
const int good = 115;
const int toomuch = 180;

Servo myservo;
  
void setup() {
  Serial.begin(115200);  // Debugging only
  Serial.println("Starting plant clock");
  myservo.attach(servo_pin);  // attaches the servo on pin 9 to the servo object
  
}


void loop() {
  myservo.attach(servo_pin);  // attaches the servo on pin 9 to the servo object
  
  float soil = analogRead(soil_pin);
  Serial.println(soil);
  int pos;  
  
  if(soil > 1000) {
    go_to_position(toomuch);
  }
  else if (soil > 900) {
    go_to_position(good);
  }
  else if (soil > 800) {
    go_to_position(ok);
  }  
  else if (soil > 500) {
    go_to_position(waterme);
  }
  else {
    go_to_position(dry);
  }
  
  myservo.detach();
  delay(1000);

}

int current_pos = 0;

void go_to_position(int desired_pos) {
  Serial.println("Current = " + (String)current_pos);
  Serial.println("Desired= " + (String)desired_pos);

  
  if (current_pos == desired_pos)
    return;
  
  if (desired_pos > current_pos) {
    Serial.println("Increasing");
    for (int pos = current_pos; pos <= desired_pos; pos += 1) { // goes from 0 degrees to 180 degrees
      // in steps of 1 degree
      Serial.println(pos);
      myservo.write(pos);              // tell servo to go to position in variable 'pos'
      current_pos = pos;
      delay(15);                       // waits 15ms for the servo to reach the position
      
    }
  }
  else {
    Serial.println("descreasing");
    for (int pos = current_pos; pos >= desired_pos; pos -= 1) { // goes from 180 degrees to 0 degrees
      Serial.println(pos);
      myservo.write(pos);              // tell servo to go to position in variable 'pos'
      current_pos = pos;
      delay(15);                       // waits 15ms for the servo to reach the position
    }
  }
  Serial.println("Done");
}