Sample
Read the light sensor at a regular interval so changes can be observed.
Personal Electronics Project
Plant Monitor
I built this during my freshman year of high school because I wanted to understand what a plant needed throughout the day. It monitored light, temperature, humidity, and soil moisture, with readings shown on an LCD.
- Arduino
- DHT11
- Soil moisture
- Photoresistor
- LCD
Why I made it
I wanted to see how much light a plant received and use soil moisture to help tell when it needed water. It was an early project where I could write a little code, change something in the real world, and watch the sensor readings respond.
Signal path
Read the environment, then make it visible.
Light + soilLight level + moisture
AirTemperature + humidity
ArduinoRead and organize
LCDShow conditions
Prototype logic
Small loops, observable results.
Combine
Pair the light value with temperature and humidity measurements.
Display
Present the readings on the LCD instead of leaving them only in a serial log.
Two original sensor tests
These small sketches test the sensors separately and print a reading once per second. They are examples from the build, rather than the complete soil-moisture and LCD program. The temperature file is named SHT20TempAndHumid, but its code uses a DHT11 on pin 7.
Light level · analog pin A0
int photoPin = A0;
void setup() {
Serial.begin(9600);
}
void loop() {
int light = analogRead(photoPin);
Serial.println(light);
delay(1000);
}Temperature and humidity · DHT11
#include <dht.h>
dht DHT;
#define DHT11_PIN 7
void setup(){
Serial.begin(9600);
}
void loop(){
int chk = DHT.read11(DHT11_PIN);
Serial.print("Temperature = ");
Serial.println(DHT.temperature);
Serial.print("Humidity = ");
Serial.println(DHT.humidity);
delay(1000);
}