Help my plant is dying!

House plants are not tough like driveway weeds. House plants need lots of water and sunlight to thrive which people consistently forget.

BeginnerFull instructions provided168

Things used in this project

Hardware components

Particle Argon

LED (generic)

Photo resistor

SparkFun Soil Moisture Sensor (with Screw Terminals)

Story

House plants provide a nice atmosphere whether they're huge and extravagant or something small. And believe it or not they grow, very slowly. Might as well consider them to be a pet. Like pets they need to be taken care of, but they only need a few things: sun, water, soil. Unfortunately, this project doesn't tackle the manifestation of soil. It does describe how to have the plant tell when it needs fed or watered - and no crazy barking!

The first part (feeding) only requires a few hours of sunlight a day, but the more the better. So, placing the plant close to a window seems like the logical choice. But we don't want neighbors stealing ideas for IOT projects so at night the blinds remain closed for the utmost secrecy. Now that morning rush is a real deal and sometimes a thing or two is missed, like forgetting to feed the plant! Luckily, we live in the internet age and have access to microcontrollers and sensors to communicate information autonomously. The photoresistor is a perfect sensor for detecting light and quantifying it to an analog signal to be read and sent wherever is needed. When the blinds are closed, a low level of light will be read by the sensor, and when open, a higher number will be read. Through some calibration based on physical setting, an approximate critical value can be determined that indicates if the blinds are closed or opened. This number will be read by a Particle Argon microcontroller and once crossed sends a Particle.publish event to the cloud.

A 3mm CdS photosensitive resistor was used and a link to purchasing and more information is provided here.

Next is watering. Different plants need different frequencies of watering times and amount of water at a time. A simple water level or soil moisture content sensor would do the trick here. As water contacts the sensor, the read value goes down and an approximate critical value can be determined to have the plant say, "hey I'm feelin fresh!" Similar to the photoresistor, once that critical value is passed an event can be published to the cloud.

A Soil Moisture Content Sensor was used and a link to purchasing and more information is provided here.

In this project, two Argon devices are used. One Argon (Argon1) is connected to the water level sensor and the other (Argon2) is connected to the photoresistor. It is useful to have two devices so measuring multiple plants in different locations is possible with only one light value sent to all. The way each Argon communicates is through Particle.subscribe commands. Each Argon will subscribe to the others event. So, Argon1 is subscribed to Argon2s event when the light threshold is crossed, and vice versa. The publish event will trigger a "subscribe function" that flashes an LED on/off corresponding to the state of water or light. Each Argon has LEDs for both statuses. This flow chart is shown in Figure 1.

Figure 1: Project Flow Chart

ThingSpeak is also connected to the water content data via a WebHook. Data on water content over time is useful so patterns can be observed that link plant watering and health. A sample plot of water content by sticking the sensor into a glass of water overtime is shown in Figure 2.

Figure 2: Graphical Representation of Water Levels

The two circuit diagrams used are relatively simple as shown in Figures 3 and 4.

Figure 3: Argon1 Circuit Diagram

Figure 4: Argon2 Circuit Diagram

Physically implementing the two circuits is also not too difficult as shown in Figures 5 and 6.

Figure 5: Argon2 (photoresistor) Circuit

Figure 6: Argon2 (water sensor) Circuit

There is a video demonstration on the application of the project. Water in a bottle was used instead of a plant to quickly show the LEDs turn on.

Code

int lightVal;
int waterVal;
int lightP=A0;
int waterP=A1;
int lightLEDP=D3;
int waterLEDP=D2;
int lightCrit=2000;
int waterCrit=3000;


void setup() {

pinMode(lightP,INPUT);
pinMode(waterP,INPUT);
pinMode(waterLEDP,OUTPUT);
pinMode(lightLEDP,OUTPUT);

Particle.variable("Light Value",&lightVal,INT);
Particle.variable("Water Value",&waterVal,INT);

Particle.subscribe("Light Event",lightHandle);
Particle.subscribe("Water Event",waterHandle);

}

void loop() {

lightVal=analogRead(lightP);
waterVal=analogRead(waterP);

String waterValstring = String(lightVal);
String lightValstring = String(waterVal);

if(lightVal>lightCrit){
    
    Particle.publish("Light Event","Got enough light!");
    delay(1000);
    Particle.publish("Light Status",lightValstring,PRIVATE);
    delay(1000);
    
}

if(lightVal<=lightCrit){
    
    Particle.publish("Light Event","Im blind!");
    delay(1000);
    Particle.publish("Light Status",lightValstring,PRIVATE);
    delay(1000);
    
}

if(waterVal<=waterCrit){
    
    Particle.publish("Water Event","Got enough water!");
    delay(1000);
    Particle.publish("Water Status",waterValstring,PRIVATE);
    delay(1000);
}

if(waterVal>waterCrit){
    
    Particle.publish("Water Event","Im partched!");
    delay(1000);
    Particle.publish("Water Status",waterValstring,PRIVATE);
    delay(1000);
    
}

delay(10000);

}

void lightHandle(const char *event, const char *data){
    
    if(strcmp(data,"Got enough light!")==0){
        
        digitalWrite(lightLEDP,LOW);
        //delay(5000);
        
    }
    
    else if(strcmp(data,"Im blind!")==0){
        
        digitalWrite(lightLEDP,HIGH);
        //delay(5000);
        
    }
    
    else{}
    
}

void waterHandle(const char *event, const char *data){
    
    if(strcmp(data,"Got enough water!")==0){
        
        digitalWrite(waterLEDP,LOW);
        
    }
    
    else if(strcmp(data,"Im partched!")==0){
        
        digitalWrite(waterLEDP,HIGH);
        
    }
    
    else{}
    
}

int lightVal;
int lightP=A0;
int lightLEDP=D3;
int waterLEDP=D2;
int lightCrit=2000;



void setup() {

pinMode(lightP,INPUT);

pinMode(waterLEDP,OUTPUT);
pinMode(lightLEDP,OUTPUT);

Particle.variable("Light Value",&lightVal,INT);


Particle.subscribe("Light Event",lightHandle,ALL_DEVICES);
Particle.subscribe("BeWater",waterHandle,ALL_DEVICES);

}

void loop() {

lightVal=analogRead(lightP);



if(lightVal>lightCrit){
    
    Particle.publish("Light Event","Got enough light!",ALL_DEVICES);
    delay(1000);
    
}

if(lightVal<=lightCrit){
    
    Particle.publish("Light Event","Im blind!",ALL_DEVICES);
    delay(1000);
    
}

delay(10000);

}

void lightHandle(const char *event, const char *data){
    
    if(strcmp(data,"Got enough light!")==0){
        
        digitalWrite(lightLEDP,LOW);
        
    }
    
    else if(strcmp(data,"Im blind!")==0){
        
        digitalWrite(lightLEDP,HIGH);
        
    }
    
    else{}
    
}

void waterHandle(const char *event, const char *data){
    
    if(strcmp(data,"Waters Good")==0){
        
        digitalWrite(waterLEDP,LOW);
        
    }
    
    else if(strcmp(data,"Low Water Level")==0){
        
        digitalWrite(waterLEDP,HIGH);
        
    }
    
    else{}
    
}

int waterVal; //define variable 

int waterP=A1;//define pin

int LEDwaterP=D2;
int LEDlightP=D3;

int waterPercent;


int critWater=3500;


void setup() {

pinMode(waterP,INPUT);//define inputs and outputs for the pins

pinMode(LEDwaterP,OUTPUT);
pinMode(LEDlightP,OUTPUT);

Particle.variable("Water Value",&waterVal,INT);

Serial.begin(230400);//begin serial monitor for checking values via the serial monitor

Particle.subscribe("Light Event", lightsCheck, MY_DEVICES);
Particle.subscribe("BeWater", waterCheck, MY_DEVICES);

}

void loop() {

waterVal=analogRead(waterP);

if(waterVal<critWater){

    //digitalWrite(LEDwaterP,LOW);
    Particle.publish("BeWater","Waters Good", ALL_DEVICES);
}

if(waterVal>=critWater){

    //digitalWrite(LEDwaterP,HIGH);
    Particle.publish("BeWater","Low Water Level", ALL_DEVICES);
    delay(1000);
}

waterPercent = -0.0493 * (waterVal) + 201.32;

Particle.publish("thingSpeakWaterLevel", String(waterPercent), PRIVATE);

delay(1000);

}

void lightsCheck(const char event, const chardata) {
        //When lightsCheck runs, sees which message was recieved and turns on or off LED accordingly

    if (strcmp(data,"Got enough light!")==0) {
        digitalWrite(LEDlightP,LOW);
    }
    else if (strcmp(data, "Im blind!")==0) {
        digitalWrite(LEDlightP,HIGH);
    }
    else{
    }
}

void waterCheck(const char event, const chardata) {
    //When waterCheck runs, sees which message was recieved and turns on or off LED accordingly

    if (strcmp(data,"Waters Good")==0) {
        digitalWrite(LEDwaterP,LOW);
    }
    else if (strcmp(data, "Low Water Level")==0) {
        digitalWrite(LEDwaterP,HIGH);
    }
    else{
    }
}