Plant Health Monitor

Introduction: Plant Health Monitor

About: I am a 15-year-old DIY hobbyist. I mainly focus on electronics, but I dabble in other areas as well. (If you noticed my profile picture I also am a crypto enthusiast)

Hello, again. The reason for this project was my little sister. Her birthday is coming up, and she loves two things- nature (both flora and fauna) as well as little trinkets and such. So I wanted to combine these two things and make her a birthday present, which coincided with the Instructables Planter Contest. The project is a planter for an indoor plant that measures plant health and uses an LED to indicate the "happiness" of the plant. I knew she would love it, and the timing was perfect since her birthday is on the 30th of July. Feel free to wish her a happy birthday in the comments, I will be sure to show her. Without further delay, let's begin!


  1. Arduino Nano- Amazon
  2. DHT11 Temperature/Humidity Sensor Module- Amazon
  3. Plenty of F/F Jumper Wires- Amazon
  4. Soil Moisture Sensor- Amazon
  5. 2x LED (Color of your choice)
  6. Small Planter (With a hole in the bottom)
  7. Duck Tape
  8. 3D Printer (Optional)
  9. Hot Glue Gun
  10. Soldering Iron

Step 1: The Circuitry

First off, what exactly will it do? The planter will use the moisture sensor to calculate how much water the plant is getting. It will use the DHT11 to see if the temperature is at an acceptable level for the plant. It will use pre-programmed baselines for what these "vital signs" should be within, which I will discuss later. Now that that's out of the way, use the diagram above top wire your circuit. In real life, however, do not use a breadboard as this will be much too large. I soldered the LEDs to the jumper wires, but with everything else, I used the F/F plugs. Another consideration to make is the ground connection. You may have noticed the Arduino has 2 ground pins, and we need 4 for this circuit. I connected all the ground wires and Duck Taped them to save time. You, however, may want to use heat shrinks.

*Note- I will be using a slightly different Soil Moisture Sensor in my project (picture above) but the wiring is the same. If your sensor is like mine, just make sure you connect the "A0" pin to the Analog 0 on the Arduino.

Step 2: Code

First, we need to install the DHT11 library. Click on this link to download it. To add the .zip DHT11 lib to you libraries, go to "Sketch--> Include Libraries--> Add .ZIP Library" in the IDE, and select the ZIP file that you downloaded from GitHub. Download the Arduino sketch below and upload it to your board**. If you have any questions or tips about it, kindly leave them in the comments. Basically, the sketch takes a temperature and moisture reading every 60 seconds and sets the LEDs to HIGH or LOW according to the data.

**If you are using the Arduino Nano I suggested, you will need to change the processor. To do this, go to Tools-Processor-ATmega328P (Old Bootloader).

Step 3: Vital Signs

The reason I chose those baselines in the program (Temperature Maximum= 28° C, Moisture Minimum= 350***) is simple- experimentation. I tested different soils with various moisture contents, and, combined with my knowledge of plants, decided the least amount of moisture in the soil is 700***. As for the temperature, I got that level from HowStuffWorks.

***Honestly, I do not know what unit this is- I used the code from Instructables User fbasaris. The higher the number, the less moisture in the soil.

Step 4: Glue the Sensors

Hot Glue the soil moisture and temperature sensors in place, as shown. Then, tape the wires to the bottom of the planter. While the glue gun is out, seal any connections that may be exposed to water. We don't want this to short circuit.

Step 5: Tape Components

Tape all of the components in place, wherever they fit. Each planter is different, so placement varies from person to person. As long as everything connects well, it doesn't really matter as the cover will hide messy wiring. Refer to the picture above.

Step 6: The Case

For my case, I opted for a 3D Printed enclosure that lets the planter hang from the top (STL file attached). However, you can make your encasement however you like, and it is unlikely that you will use my exact design due to the variance in planters. You are kind of on your own with this step, but here are your criteria:

  1. Make sure it covers up messy wires and components
  2. Leave enough room inside for the circuitry
  3. Make sure the LEDs are visible
  4. Leave room for the power cord
  5. Preferably, make it aesthetically appealing (this is a flower vase after all)

Step 7: Finished

Now it's time to pour soil into the planter. This is pretty self-explanatory. Plug the planter into a wall adapter, and you have a fully-functioning electronic planter! Now you can watch your friend (the plant, that is) grow and blossom!

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