ESP32 Plant Monitoring System

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Table of Contents

• ESP32 Plant Monitoring System
  • Table of Contents
  • Overview
  • Shopping List
  • Setup
    • Circuit Schematic
    • ESP32 Pinout
      • 30 Pin
      • 38 Pin
    • Configuration
      • WiFI Configuration
      • Other Configuration
    • Libraries
      • External Libraries
    • Uploading
  • Images
  • 3D Print
  • TODO
  • Links

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Overview

This project implements a monitoring system using an ESP32 microcontroller to measure and display temperature, humidity, and CO2 levels in real-time.

This is designed to be used to monitor the environment when growing plants

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Shopping List

Here is a list of parts used in this project

Note

Amazon links are non-affiliate

NAME	PRICE	COUNT	DESCRIPTION	LINK	NOTE
ESP32	$5	1	Microcontroller	Amazon	USB-C ESP32 Amazon
DHT22	$3	1	Temp/Humidity Sensor	Amazon
MQ-135	$3	1	CO2 Sensor	Amazon
OLED Display	$3	1	0.96" OLED Display 128x64 SSD1306	Amazon
Kasa Smart Plug	$7.50	2	TP-Link Kasa Smart Plug HS103	Amazon	Intake and exhaust fans smart plugs
Rocker Switch	$0.60	2	Rocker Switch On/Off 2 Pin	Amazon
1K Ω Resistor	$0.25	1	1K Ohm Resistor	Amazon	MQ-135 analog pin
10K Ω Resistor	$0.25	0/1/2	10K Ohm Resistor	Amazon	Most DHT22 sensor modules have a built-in resistor
Wire/Breadboard	$1	0/1	Jumper wire or breadboard	Amazon	Optional depending on setup
Breakout Board	$4	0/1	ESP32 Breakout Board GPIO	Amazon	Optional depending on setup
Buck Converter	$1	0/1	LM2596 DC-DC Buck Converter Step Down	Amazon	Optional depending on setup
Barrel Jack	$1	0/1	Female DC Barrel Jack Panel Adapter	Amazon	Optional depending on setup
1N5819 Diode	$0.1	0/1	1N5819 Schottky Diode	Amazon	Optional depending on setup
1000µF Capacitor	$0.4	0/1	1000uF 10V 8x12mm Capacitor	Amazon	Optional depending on setup

Tip

Lower prices can be found if you shop around

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Setup

Once you have all the required parts in hand, you can start wiring

Circuit Schematic

ESP32 Pin	Destination	Type	Power Requirements (Volts)	ESP32 VCC Pin	ESP32 GND Pin
27	DHT22	Digital	3.3 - 5	3.3V	GND
35	CO2 Sensor	Analog	5	5V	GND
21	OLED SCL	SCL	3.3	3.3V	GND
22	OLED SDA	SDA	3.3	3.3V	GND
19	Rocker Switch	GPIO			GND

Note

Feel free to change the pins used on the ESP32, just note, if you change the pins, you will need to update the values in the code.

ESP32 Pinout

30 Pin

38 Pin

Configuration

You will need to define values to suite your needs. Variables are defined in config.h

WiFI Configuration

Here is a list of WiFi variables that must be defined and their descriptions...

WIFI_SSID : WiFi SSID (network/WiFi name)

WIFI_PASSWORD : WiFi password

WIFI_HOSTNAME : Hostname of ESP32 to set

Other Configuration

Other variables in the code can be changed to suite your needs

Libraries

You will need to install additional libraries.

In Arduino IDE, go to library manager and search and install the required libraries listed in the DEPENDENCIES section in main.ino

External Libraries

• KasaSmartPlug Github

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Uploading

I use Arduino IDE to upload the code to the board. I had to install additional drivers (Download) to get connected to my board.

I installed the ESP32 boards and selected ESP32dev board.

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Images

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3D Print

The housing to hold the ESP32 can be 3D printed.

The 3D model files are located under the 3D-models directory.

Name	Image	Link	Author
ESP32-Plant Case		ESP32-Plant Case Case	ConnerWill
DHT22 Case		Over-engineered DHT22 / AM2302 Board Case	SciMonster
MQ-135 Case		MQ-2 Sensor Case	RJGII

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TODO

• [] Improve wiring/setup instructions
• [] Finish 3D models
• [] Add finished product images
• [] Improve code

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Links

• microcontrollerslab.com/esp32-dht11-dht22-web-server
• blog.asksensors.com/air-quality-sensor-mq135-cloud-mqtt
• maker.pro/everything-esp/projects/how-to-control-a-relay-module-with-esp32
• thingiverse.com/thing:4521313
• thingiverse.com/thing:2893581
• javl.github.io/image2cpp
• github.com/ConnerWill/KasaSmartPlug

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