Pot Head! The Candy Man

Pot Head! The Friendly Planter That Feeds You Candy When You Water It!

My project uses a servo, an LED and a Soil Moisture Detecter to remind the owner that their plant needs to be watered and then rewards the owner with a small piece of candy when the job gets done! Apart from changing from a happy face to a sad face, It also emails the owner when things get too dry. Its a very persuasive plant!

The Three Components Used Are:

Soil Moisture Sensor

Servo Motor

LED

The Internals of the Device

The image above shows the internal mechanism of the device. A servo motors has two ice cream sticks attached to it. On the far end of the sticks is a drinking straw. This straw acts as a candy reservoir. We put candies inside the straw, and as the straw moves to position shown, the candies fall down the hole and slide outside. The straw will only move to this position when the plant is watered. The straw has a piece of paper attached to it. This paper has three expressions. A beaming smile, a normal smile and a sad face. If the moisture level is normal, we see the normal smile. If the moisture level goes below a certain point, the straw moves and we see the sad face. If the user gives waters the soil, the straw moves again and we see the beaming smile from the cutout. The straw stays in this position just long enough for a couple of candies to fall out and then changes it position.

The Circuit Board

Code

int sensor_pin = A5;	/* Soil moisture sensor O/P pin */
int ledPin= D2;
int sensor_analog=0;
int moisture_percentage;
int last_published = -1;//event publish record
    
int servoPin = A2;
Servo myServo;
int servoPos = 90;
bool delayOrNot=true;

void setup() {
    
 // Serial.begin(9600);	/* Define baud rate for serial communication */
  Particle.variable(  "moisture" , sensor_analog);
  
//  Serial.begin(9600);
  myServo.attach( A2 );
  
  //Register our Particle to control the servo
   Particle.function("servo", servoControl);
  
  
    // Keep a cloud variable for the current position
  Particle.variable(  "servoPos" , servoPos);
  
  pinMode(sensor_pin,INPUT);
 pinMode(ledPin,OUTPUT);
 analogWrite(ledPin,HIGH);

}

void loop() {
 
 
  sensor_analog = analogRead(sensor_pin);
  Serial.println(sensor_analog);
  
  
if (sensor_analog > 3500){
   
     servoControl("40"); //when dry
    delayOrNot=true;
    analogWrite(ledPin,200);
    sendmessage (  );
}
 
 
 else{
     if(delayOrNot==true){
     servoControl("71");
     }
     delay(300);
     servoControl("76");
     delayOrNot=false;
     analogWrite(ledPin,0);
 }
 
 
  
  moisture_percentage =sensor_analog/10000;
 
}


int servoControl(String command)
{
    // Convert
   int newPos = command.toInt();
   // Make sure it is in the right range
   // And set the position
   servoPos = constrain( newPos, 0 , 180);

   // Set the servo
   myServo.write( servoPos );

   // done
   return 1;
}

void sendmessage (  )
{if( last_published + 60000 < millis() ){
    Particle.publish("SoilStatus", "not enough water!",60,PUBLIC);
    last_published = millis();
    }

Click to Expand

I used IFTTT to send me an email whenever the moisture levels were too low.

Problems faced

One of the most erratic aspect of this project was the moisture detector. It was working fine but by the end it stopped working. If I were to re-do this project I would want to develop a better understanding of how the moisture detector works.

I also faced problems with the Argon board. It wouldn't connect to the WIFI and eventually the board had to be replaced.

I built the candy dispensing mechanism using craft paper and plain paper. I made two prototypes but I am still not fully satisfied by the mechanism. If I were to re-do this project I would make a dispensing system that was easier to dismantle so I can troubleshoot more easily.

How to connect the servo motor

https://www.allaboutcircuits.com/projects/servo-motor-control-with-an-arduino/

Reading the servo motor

https://www.arduino.cc/en/Reference/ServoRead

What do the different light patterns mean on the micro controller

https://docs.particle.io/tutorials/device-os/led/photon/

Inspiration for the candy mechanism

https://www.youtube.com/watch?v=aomavIH9Y64