Farm Urban (Arduino Sensors)

Code for Arduino Sensors

This code is built for the following boards:

• Arduino Leonardo
• Arduino UNO R4 WiFi
• Arduino UNO WiFi R2
• ESP32 S3 DevKitC 1 N16R8

Other boards might be added with time, if need be. However, should you need to test on another board, supported by PlatformIO, the easiest way would be to add a new environment in the platformio.ini file. The current code base is built to work with Arduino which means choosing boards supported by the Arduino platform is easier.

You can comment/uncomment, one of the lines under platformio in the configuration file to target just one which is easier/faster for local use. Otherwise the commands you need are

Name/Action	Command Format	Example
Build (default environments)		pio run
Build (specific environment)	pio run --environment {env-name}	pio run --environment uno_wifi_rev2
Upload (specific environment)	pio run --environment {env-name} --target upload	pio run --environment uno_wifi_rev2 --target upload
Test		pio test --environment native
Clean (default environments)n		pio run --target fullclean
Clean (specific environment)	pio run --environment {env-name} --target fullclean	pio run --environment leonardo --target fullclean

WiFi

Boards that support WiFi are generally easier to work with because they transmit directly to Home Assistant. The WiFi network you connect to is controlled by the common build_flags_wifi in platformio.ini.

• To connect to a public network, you only need to configure -DWIFI_SSID=\"<your-network>\" for example, `-DWIFI_SSID="Airport_Free_WiFi"
• To connect to a simple WPA2 network, you need to set both -DWIFI_SSID=\"<your-network>\" and -DWIFI_PASSPHRASE=\"<your-value>\"
• To connect to an 802.1x or enterprise network, you need to set ; -DWIFI_PASSPHRASE=\"<your-value>\", -DWIFI_ENTERPRISE_USERNAME=\"<your-value>\", and -DWIFI_ENTERPRISE_PASSWORD=\"<your-value>\". Optionally, you may need -DWIFI_ENTERPRISE_IDENTITY=\"<your-value>\" or -DWIFI_ENTERPRISE_CA=\"<your-value>\". This is for networks such as those used at hospitals for staff members, universities, shared accommodation or maybe your workplace.

Note

1. Networks with captive portals do not work.
2. Networks with spaces need to be escaped appropriately. For example, to connect to a network named ASK4 Wireless, you should use -DWIFI_SSID=\"ASK4\ Wireless\". To connect to a network named Jen's iPhone, you should use -DWIFI_SSID=\"Jen\'s\ iPhone\". At times, the device is unable to connect when there are special characters, renaming your phone should fix it, e.g Jen's iphone -> JensiPhone.
3. Arduino UNO R4 WiFi, does not (yet) support enterprise WiFi.

WiFi Firmware

The WiFi modules may need firmware updates to work properly such as when using an older board or you have not used a particular board for a while. In some cases, multiple attempts may be required. See:

• Arduino UNO R4 WiFi
• Arduino UNO WiFi Rev2

Sensors

There are a number of sensors used in the farm for different purposes.

Sensor	Purpose	Pin	Flag	Macro
Light		A0	SENSORS_LIGHT_PIN	HAVE_LIGHT
CO2		A1	SENSORS_CO2_PIN	HAVE_CO2
EC		A2	SENSORS_EC_PIN	HAVE_EC
pH		A3	SENSORS_PH_PIN	HAVE_PH
Moisture		A4	SENSORS_MOISTURE_PIN	HAVE_MOISTURE
DHT22	Humidity and Temperature (Air)	2	SENSORS_DHT22_PIN	HAVE_DHT22
SEN0217	Flow Sensor	3	SENSORS_SEN0217_PIN	HAVE_FLOW
DS18S20	Temperature (Wet)	4	SENSORS_DS18S20_PIN	HAVE_TEMP_WET
SEN0204	Water Level Sensor	5	SENSORS_SEN0204_PIN	HAVE_WATER_LEVEL_STATE
AHT20	Humidity and Temperature (Air)	I2C	HAVE_AHT20	HAVE_AHT20
ENS160	Air Quality & Multi Gas	I2C	HAVE_ENS160	HAVE_ENS160

When you start using this, you might not have/need all of these. You can remove the ones you do not have/need by editing build_flags in platformio.ini. For example, if you do not have pH sensor, you can remove the line containing -DSENSORS_PH_PIN=A3. By default, when a sensor is not enabled, the value is -1 to signify invalid.

Important

The EC and pH probes may require calibration. The values are stored in EEPROM (otherwise referred to as KeyValue store). This code may be added to the code base at a later time but in the mean time you can have a look at logic here.

The EC and pH probes require temperature compensation. The best value to use for this is the wet temperature. However, if the wet temperature sensor is not configured, the air temperature is used which may not be as accurate. A build time warning is produced. The air temperature may also used if the wet temperature reading is between -1000 and -1002, limits inclusive which is usually transient.

Calibration

The EC and pH sensor need calibration for the first time use or after not being used for an extended period of time. There are detailed guides for calibration at:

• For pH
• For EC (K=1)

For simplicity doing calibration and to allow you recalibrate on the fly, you can use a toggle button or PCB fuse to short the calibration pin (defaults to 12) to ground. Calibration mode is exclusive and when in it, no data is collected or transmitted. When in this mode values will be printed on your Serial Monitor/Terminal every second (configurable in code), for example: Temperature: 25.0 ^C EC: 1.41ms/cm pH: 7.12. You can then issue calibration command via the same monitor or terminal.

Command	Description
enterph	enter the calibration mode for pH
calph	calibrate with the standard buffer solution, two buffer solutions(4.0 and 7.0) will be automatically recognized
exitph	save the calibrated parameters and exit from calibration mode
enterec	enter the calibration mode
calec	calibrate with the standard buffer solution, two buffer solutions(1413us/cm and 12.88ms/cm) will be automatically recognized
exitec	save the calibrated parameters and exit from calibration mode
clear	Clear EEPROM data

The last two characters of the command designate which sensor is being configured e.g. enterph is for the pH sensor while enterec is for the EC sensor.

Data Transmission

The code base supports either sending data to Home Assistant (MQTT) or printing out JSON via Serial. Data is sent to HomeAssistant, if the board has network support (e.g. WiFi). HomeAssistant is capable enough to replay the information to any other destination including InfluxDB (which we used to support in this repository).