Garduino

Greenhouse monitoring using ESP32.

Features

• Controls 24V water waterpump and starts it once a day to water the plants for a period of time
• Device status is displayed on a small 0.91 inch OLED screen
• Includes a manual mode button to enable/disable the water valve manually
• Time is stored in a battery-powered DS3231 realtime clock

Sensors

Target	Sensor	Location	Amount
Light	TSL2591	Inside	1
Soil moisture	Capacitive Soil Moisture Sensor v2.0	Inside	8
Temperature/pressure/humidity	BME280	Inside	1
Air temperature	DS18B20	Outside	1
Water temperature	DS18B20	Outside	1

Readings from the sensors are sent to a MQTT server over WiFi (if available).

Wiring

AZ-Delivery Devkit V4

Device	Pin Label	ESP32 Pin	Type
TCA9548A I2C Expander	SDA	4	I2C bus 0 (address: 0x70)
TCA9548A I2C Expander	SCL	22	I2C bus 0 (address: 0x70)
DS3231 Realtime Clock	SDA	4	I2C bus 0 (address: 0x68)
DS3231 Realtime Clock	SCL	22	I2C bus 0 (address: 0x68)
AT24C32 EEPROM on DS3231	SDA	4	I2C bus 0 (address: 0x57)
AT24C32 EEPROM on DS3231	SCL	22	I2C bus 0 (address: 0x57)
PCF8574 Digital Expander	SDA	4	I2C bus 0 (address: 0x20)
PCF8574 Digital Expander	SCL	22	I2C bus 0 (address: 0x20)
MCP3008 Analog Expander	CLK	18	SCK
MCP3008 Analog Expander	DOUT	19	MISO
MCP3008 Analog Expander	DIN	23	MOSI
MCP3008 Analog Expander	CS	5	SS
DS18B20 Temperature Sensors	GPIO	13	Digital Input
Buzzer	GPIO	25	Digital Output
Single Channel Relay	GPIO	26	Digital Output
Manual Run Button	GPIO	39	Digital Input
Power Button	GPIO	36	Digital Input

TCA9548A

Device	Pin Label	TCA9548A Pin	Address
TSL2591 light sensor	SDA	SD0	0x29
TSL2591 light sensor	SCL	SC0	0x29
BME280 barometer	SDA	SD1	0x76
BME280 barometer	SCL	SC1	0x76
0.91" OLED Display	SDA	SD2	0x3C
0.91" OLED Display	SCL	SC2	0x3C

PCF8574

Device	Type	PCF8574 Pin
Watering Indication LED (White)	Digital Output	0
Manual Run LED (Yellow)	Digital Output	2
Network LED (Blue)	Digital Output	1
Power LED (Red)	Digital Output	3

MCP3008

Device	Type	MCP3008 Pin
Capacitive Soil 1	Analog Input	0
Capacitive Soil 2	Analog Input	1
Capacitive Soil 3	Analog Input	2
Capacitive Soil 4	Analog Input	3
Capacitive Soil 5	Analog Input	4
Capacitive Soil 6	Analog Input	5
Capacitive Soil 7	Analog Input	6
Capacitive Soil 8	Analog Input	7

3D Printable Parts

Part	Amount
Buck converter bottom	1
Buck converter top	1
Buck converter icon	1
Buck converter latch	2

Output

Example of cycle report on serial line:

00:00:00.063  ========================
00:00:00.064  =    garduino v4.0.0   =
00:00:00.064  ========================
00:00:00.065  Board:       AZ-Delivery ESP-32 Dev Kit C V4
00:00:00.075  Arduino:     2.0.7
00:00:00.075  ESP-IDF:     v4.4.4
00:00:00.080  Local time:  17:46:17
00:00:00.485  *******************************************
00:00:00.486  Wakeup reason: timer (60 sec)
00:00:00.487  *******************************************
00:00:00.488  WiFi - SSID: my_ssid
00:00:00.499  WiFi - Connecting...
00:00:00.708  WiFi - Connected.
00:00:00.709  WiFi - Hostname: garduino
00:00:00.709  Wifi - IP address: 192.168.2.2
00:00:00.710  ================================
00:00:00.721  MQTT - Timeout set to 30 seconds
00:00:00.721  MQTT - Broker: 192.168.2.1:1883
00:00:00.722  MQTT - Connecting...
00:00:00.775  MQTT - Connected.
00:00:00.776  ================================
00:00:00.777
00:00:00.777  ************************************
00:00:00.778        Watering: No
00:00:00.788          Period: 60 sec
00:00:00.789  Daily schedule: 19:00:00
00:00:00.789    Current time: 17:46:17
00:00:00.791        Last run: 2023-03-21 19:08:11
00:00:00.802  ************************************
00:00:00.802
00:00:00.803  MQTT - Publishing sensor data...
00:00:00.813
00:00:00.814  Inside
00:00:00.814  ------
00:00:00.814
00:00:00.815  Light:            350.67 lx
00:00:00.821  Humidity:         44.5%
00:00:00.822  Temperature:      25.14 °C
00:00:00.822  Pressure:         1002.44 hPa
00:00:00.840  Soil-1 wet:       0%
00:00:00.841  Soil-2 wet:       0%
00:00:00.851  Soil-3 wet:       0%
00:00:00.852  Soil-4 wet:       0%
00:00:00.852  Soil-5 wet:       0%
00:00:00.852  Soil-6 wet:       0%
00:00:00.853  Soil-7 wet:       98%
00:00:00.863  Soil-8 wet:       0%
00:00:00.854  System:           23.75 °C
00:00:00.854
00:00:00.854  Outside
00:00:00.855  -------
00:00:00.865
00:00:00.962  Temperature:      17.75 °C
00:00:00.967
00:00:00.967  Water
00:00:00.967  -----
00:00:00.967
00:00:00.968  Temperature:      18.25 °C
00:00:00.968
00:00:00.968  WIFI
00:00:00.969  ----
00:00:00.979
00:00:00.981  RSSI:             -63 dBm
00:00:00.981
00:00:00.981  **********************************************
00:00:00.982
00:00:16.558  MQTT - Published 16 messages.
00:00:16.559  MQTT - Disconnecting...
00:00:16.863
00:00:16.864  ******************************
00:00:16.865  **  Going to sleep... Bye.  **
00:00:16.866  ******************************

Local NTP Server

Setup a local NTP server instead of fetching this information online every time.

sudo apt-get install ntp

Verify installation:

sntp --version

Switch the server pool to the ones closest to your location. Go to https://support.ntp.org/bin/view/Servers/NTPPoolServers and find the nearest pool, e.g. Europe. Update /etc/ntp.conf accordingly:

	   server 0.europe.pool.ntp.org
	   server 1.europe.pool.ntp.org
	   server 2.europe.pool.ntp.org
	   server 3.europe.pool.ntp.org

Restart the server:

sudo service ntp restart

Check the status:

 sudo service ntp status

You can now use this machine for NTP time synchronization on the ESP32.